Every ledger is cleared on a compact, and a retrieval floor becomes something the model maintains (#163)

alembic/versions/0103_retrieval_tuning_events.py

@@ -0,0 +1,75 @@
+"""retrieval_tuning_events — why a floor is where it is (#4102)
+
+Revision ID: 0103
+Revises: 0102
+Create Date: 2026-09-17
+
+Milestone 416 stops shipping similarity thresholds as values somebody has to
+defend, and hands the adjustment to the model that reads the surface's own
+telemetry. The operator's decision:
+
+    "the floor should be chosen and adjusted by the model using it… the user
+    should be able to touch it but the model should be the thing handling it 9
+    times out of 10."
+
+The number itself already has a home — the generic settings table. What has no
+home is the ARGUMENT, and once the values move on their own the argument is the
+part an operator needs: what changed, from what to what, who moved it, and on
+what evidence. This table is that trail, and it is what makes the delegation
+reviewable rather than merely automatic.
+
+Nothing is backfilled. A surface with no rows here is sitting on its shipped
+starting point, which is a true and useful thing for the history to say.
+"""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0103"
+down_revision = "0102"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "retrieval_tuning_events",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        # FK-free, like retrieval_logs and app_logs: the record of why a number
+        # is where it is must outlive the account that moved it.
+        sa.Column("user_id", sa.Integer(), nullable=True),
+        # Also the surface's `retrieval_logs.source`, so a change can be read
+        # next to what the change did.
+        sa.Column("surface", sa.Text(), nullable=False),
+        sa.Column("dial", sa.Text(), nullable=False),
+        # Nullable: the first change to a surface has no stored predecessor. It
+        # moved off the shipped starting point, which is a different event from
+        # moving off a value somebody chose.
+        sa.Column("old_value", sa.Float(), nullable=True),
+        sa.Column("new_value", sa.Float(), nullable=False),
+        sa.Column(
+            "actor", sa.Text(), nullable=False, server_default=sa.text("'model'")
+        ),
+        # Non-null here; non-BLANK is enforced at the service boundary, because
+        # a column that merely forbids NULL is satisfied by "" and a required
+        # field that accepts "" is a formality.
+        sa.Column("reason", sa.Text(), nullable=False),
+    )
+    # The only read this table has: one surface's history, newest first.
+    op.create_index(
+        "ix_retrieval_tuning_surface_created",
+        "retrieval_tuning_events",
+        ["surface", sa.text("created_at DESC")],
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(
+        "ix_retrieval_tuning_surface_created", table_name="retrieval_tuning_events"
+    )
+    op.drop_table("retrieval_tuning_events")

frontend/src/views/SettingsView.vue

@@ -97,6 +97,20 @@ const kbToolRuleThreshold = ref("0.68");
 // prose rather than anything a tool produced (#3852).
 const kbPromptRuleThreshold = ref("0.72");
 const kbReportPrefThreshold = ref("0.72");
+// The BUDGETS, one per arm (#4102). Until this step only auto-inject had one
+// and every other arm's ceiling was a module constant nobody could reach — so
+// the only control an operator had over a noisy surface was to raise its bar,
+// which discards the surface's best candidates along with its worst. A budget
+// keeps the top of the ranking and drops the tail, which is what was wanted.
+const kbWritePathTopK = ref("3");
+const kbRuleHintTopK = ref("5");
+const kbToolRuleTopK = ref("5");
+const kbPromptRuleTopK = ref("3");
+const kbReportPrefTopK = ref("3");
+// What has been changed about retrieval, newest first — the review surface for
+// changes the model made on the operator's behalf (#4102).
+const tuningEvents = ref<TuningEvent[]>([]);
+const loadingTuning = ref(false);
 // Near-duplicate report floors, one per record kind (services/dedup.py).
 // Snippets are single-chunk, so their floor sits below the 0.90 write-time
 // gate and catches what it lets through. Notes/tasks are scored at chunk
@@ -149,6 +163,37 @@ async function saveRetention() {
   }
 }
 
+// One entry in the retrieval tuning trail (#4102). Mirrors
+// RetrievalTuningEvent.to_dict() — `old_value` is null for the first change to
+// a surface, which is a different event from moving off a value somebody chose
+// and renders differently below.
+interface TuningEvent {
+  id: number;
+  created_at: string | null;
+  surface: string;
+  dial: string;
+  old_value: number | null;
+  new_value: number;
+  actor: string;
+  reason: string;
+}
+
+async function loadTuningHistory() {
+  loadingTuning.value = true;
+  try {
+    const res = await apiGet<{ events: TuningEvent[] }>(
+      "/api/retrieval/tuning-history?limit=25",
+    );
+    tuningEvents.value = res.events ?? [];
+  } catch {
+    // A history that cannot be read is not worth a toast on page load — the
+    // panel says so itself, and the settings above are still usable.
+    tuningEvents.value = [];
+  } finally {
+    loadingTuning.value = false;
+  }
+}
+
 async function saveKbInject() {
   const t = Math.min(1, Math.max(0, Number(kbInjectThreshold.value) || 0));
   const k = Math.min(10, Math.max(1, Math.floor(Number(kbInjectTopK.value) || 1)));
@@ -173,6 +218,22 @@ async function saveKbInject() {
   const trT = Math.min(1, Math.max(0, Number(kbToolRuleThreshold.value) || 0.68));
   const prT = Math.min(1, Math.max(0, Number(kbPromptRuleThreshold.value) || 0.72));
   const rpT = Math.min(1, Math.max(0, Number(kbReportPrefThreshold.value) || 0.72));
+  // The budgets, clamped the way the server clamps them: a whole number in
+  // [1, 10]. Never 0 — an arm turned off is turned off by its switch, and a
+  // budget of zero would run the search, log the retrieval and render nothing,
+  // which reads in the telemetry exactly like a bar nothing cleared.
+  const asK = (v: string, d: number) =>
+    Math.min(10, Math.max(1, Math.floor(Number(v) || d)));
+  const wpK = asK(kbWritePathTopK.value, 3);
+  const rhK = asK(kbRuleHintTopK.value, 5);
+  const trK = asK(kbToolRuleTopK.value, 5);
+  const prK = asK(kbPromptRuleTopK.value, 3);
+  const rpK = asK(kbReportPrefTopK.value, 3);
+  kbWritePathTopK.value = String(wpK);
+  kbRuleHintTopK.value = String(rhK);
+  kbToolRuleTopK.value = String(trK);
+  kbPromptRuleTopK.value = String(prK);
+  kbReportPrefTopK.value = String(rpK);
   kbInjectThreshold.value = String(t);
   kbInjectTopK.value = String(k);
   kbDupThresholdSnippet.value = String(dupSnip);
@@ -211,6 +272,15 @@ async function saveKbInject() {
       // and a constant that lands under the bar is a dead arm, not a quiet
       // one (#3860).
       kb_reportpref_threshold: String(rpT),
+      // The budgets. Every one of these keys is recognised by the server as a
+      // retrieval dial, so this save is recorded in the tuning history as a
+      // change the OPERATOR made — which is the one entry the model must not
+      // quietly tune back.
+      kb_writepath_top_k: String(wpK),
+      kb_rulehint_top_k: String(rhK),
+      kb_toolrule_top_k: String(trK),
+      kb_promptrule_top_k: String(prK),
+      kb_reportpref_top_k: String(rpK),
       kb_duplicate_threshold_snippet: String(dupSnip),
       kb_duplicate_threshold_note: String(dupNote),
       kb_duplicate_threshold_task: String(dupTask),
@@ -218,6 +288,10 @@ async function saveKbInject() {
     });
     kbInjectSaved.value = true;
     setTimeout(() => (kbInjectSaved.value = false), 2000);
+    // The save just appended to the history it sits above, so re-read it —
+    // otherwise the panel shows a trail that is stale by exactly the change
+    // the operator is looking at it to confirm.
+    await loadTuningHistory();
   } catch {
     toastStore.show('Failed to save auto-inject settings', 'error');
   } finally {
@@ -672,6 +746,27 @@ onMounted(async () => {
   if (allSettings.kb_writepath_threshold !== undefined) {
     kbWritePathThreshold.value = allSettings.kb_writepath_threshold;
   }
+  if (allSettings.kb_writepath_top_k !== undefined) {
+    kbWritePathTopK.value = allSettings.kb_writepath_top_k;
+  } else if (allSettings.kb_autoinject_top_k !== undefined) {
+    // The write path shared auto-inject's ceiling until it was given its own
+    // key, so an install that tuned the shared one must keep seeing that value
+    // here — the server falls back the same way.
+    kbWritePathTopK.value = allSettings.kb_autoinject_top_k;
+  }
+  if (allSettings.kb_rulehint_top_k !== undefined) {
+    kbRuleHintTopK.value = allSettings.kb_rulehint_top_k;
+  }
+  if (allSettings.kb_toolrule_top_k !== undefined) {
+    kbToolRuleTopK.value = allSettings.kb_toolrule_top_k;
+  }
+  if (allSettings.kb_promptrule_top_k !== undefined) {
+    kbPromptRuleTopK.value = allSettings.kb_promptrule_top_k;
+  }
+  if (allSettings.kb_reportpref_top_k !== undefined) {
+    kbReportPrefTopK.value = allSettings.kb_reportpref_top_k;
+  }
+  await loadTuningHistory();
   if (allSettings.kb_duplicate_threshold_snippet !== undefined) {
     kbDupThresholdSnippet.value = allSettings.kb_duplicate_threshold_snippet;
   }
@@ -1510,13 +1605,27 @@ async function deleteUser(userId: number) {
             Stricter than the prompt threshold above on purpose. Any two pieces of
             code look somewhat alike — shared keywords, indentation, structure — so
             resemblance scores start higher for code than for prose, and a bar tuned
-            for prompts flags unrelated code as prior art. Lower this if genuine
-            duplicates go unnoticed; raise it if you're being offered snippets that
-            have nothing to do with what's being written. Snippets recorded at the
+            for prompts flags unrelated code as prior art. Claude keeps this
+            one current from what the arm actually surfaced and refused; set it
+            yourself if you disagree with where it has landed. Snippets recorded at the
             exact file are always shown regardless — those are prior art by
             location, not by resemblance.
           </p>
         </div>
+        <div class="field">
+          <label for="kb-writepath-topk">Max prior-art lines per edit</label>
+          <input
+            id="kb-writepath-topk"
+            v-model="kbWritePathTopK"
+            type="number"
+            min="1"
+            max="10"
+            step="1"
+            class="fs-input input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">How many snippets and issues one edit may be offered (1–10). Reach for this rather than the threshold when the hint feels long: lowering it keeps the best matches and drops the tail, while raising the bar above throws away good matches along with weak ones.</p>
+        </div>
         <div class="field">
           <label for="kb-rulehint-threshold">Standing-rule confidence threshold (0–1)</label>
           <input
@@ -1535,10 +1644,25 @@ async function deleteUser(userId: number) {
             preloaded any more, so this is the only way a rule reaches a write.
             Stricter than the threshold above, because there are far fewer rules
             than snippets: with a small set something always ranks first, so the
-            bar has to carry more of the judgement. Raise it if rules keep
-            arriving unread; lower it if a rule you needed never showed up.
+            bar has to carry more of the judgement. If rules arrive unread, or one
+            you needed never showed up, that is Claude's to notice and correct
+            from the telemetry — and the budget below is usually the better lever.
           </p>
         </div>
+        <div class="field">
+          <label for="kb-rulehint-topk">Max rules per edit</label>
+          <input
+            id="kb-rulehint-topk"
+            v-model="kbRuleHintTopK"
+            type="number"
+            min="1"
+            max="10"
+            step="1"
+            class="fs-input input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">How many standing rules one edit may be shown (1–10).</p>
+        </div>
         <div class="field">
           <label for="kb-toolrule-threshold">Command confidence threshold (0–1)</label>
           <input
@@ -1556,10 +1680,23 @@ async function deleteUser(userId: number) {
             query is the command text rather than code. Lower than the one above
             on purpose: a shell command is short, so it scores lower for the same
             relevance — at a shared bar this arm spoke on 2% of calls against the
-            write path's 37%. Raise it if commands attract rules that do not
-            apply; lower it if a <code>git push</code> arrives with nothing.
+            write path's 37%.
           </p>
         </div>
+        <div class="field">
+          <label for="kb-toolrule-topk">Max rules per command</label>
+          <input
+            id="kb-toolrule-topk"
+            v-model="kbToolRuleTopK"
+            type="number"
+            min="1"
+            max="10"
+            step="1"
+            class="fs-input input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">How many standing rules one command may be shown (1–10). This is the busiest arm there is — it fires before every command — so its budget is the one most worth keeping small.</p>
+        </div>
         <div class="field">
           <label for="kb-promptrule-threshold">Prompt confidence threshold (0–1)</label>
           <input
@@ -1580,6 +1717,20 @@ async function deleteUser(userId: number) {
             not a command or a file — which is why it carries its own number.
           </p>
         </div>
+        <div class="field">
+          <label for="kb-promptrule-topk">Max rules per prompt</label>
+          <input
+            id="kb-promptrule-topk"
+            v-model="kbPromptRuleTopK"
+            type="number"
+            min="1"
+            max="10"
+            step="1"
+            class="fs-input input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">How many rules or preferences one message may be shown (1–10).</p>
+        </div>
         <div class="field">
           <label for="kb-reportpref-threshold">Completion-report confidence threshold (0–1)</label>
           <input
@@ -1597,11 +1748,66 @@ async function deleteUser(userId: number) {
             written</em>, looked up when a task closes. Unlike every other bar
             here, the question this arm asks never changes — so its score is
             fixed by your preferences alone, and it will either always find one
-            or never find one. If you have written a preference for report shape
-            and it is not arriving, lower this; there is no run of calls that
-            will reveal the problem on its own.
+            or never find one, and no run of calls will reveal a dead one on its
+            own. That is why this arm is worth looking up in the panel below when
+            a report preference never seems to arrive.
           </p>
         </div>
+        <div class="field">
+          <label for="kb-reportpref-topk">Max report preferences</label>
+          <input
+            id="kb-reportpref-topk"
+            v-model="kbReportPrefTopK"
+            type="number"
+            min="1"
+            max="10"
+            step="1"
+            class="fs-input input"
+            style="max-width: 8rem"
+          />
+          <p class="field-hint">How many preferences a finished task may be shown (1–10).</p>
+        </div>
+        <!-- THE REVIEW SURFACE (#4102). These numbers are maintained by the
+             model that uses them: it reads which records each bar refused and
+             moves the dial with the argument attached. This panel is the other
+             half of that bargain — a change made on your behalf is one you can
+             read, disagree with, and set back by hand above. -->
+        <div class="tuning-history">
+          <h4 class="tuning-history-title">What has been tuned</h4>
+          <p class="field-hint">
+            Claude adjusts the bars and budgets above from what each arm actually
+            surfaced and refused, and has to state a reason to change one. Nothing
+            here needs your attention as a matter of course — it is here so that
+            when a surface behaves oddly, why it is set the way it is can be read
+            rather than guessed at. Anything you change yourself is recorded the
+            same way, and is the one entry Claude will not quietly move back.
+          </p>
+          <p v-if="loadingTuning" class="field-hint">Loading…</p>
+          <p v-else-if="!tuningEvents.length" class="field-hint">
+            Nothing has been changed yet — every surface is on the value Scribe
+            shipped. Those are starting points measured against one corpus with
+            one embedding model, not answers, so expect this to fill.
+          </p>
+          <ul v-else class="tuning-list">
+            <li v-for="ev in tuningEvents" :key="ev.id" class="tuning-item">
+              <div class="tuning-item-head">
+                <span class="tuning-surface">{{ ev.surface }}</span>
+                <span class="tuning-dial">{{ ev.dial }}</span>
+                <span class="tuning-move">
+                  <template v-if="ev.old_value !== null">{{ ev.old_value }} →</template>
+                  <template v-else>set to</template>
+                  {{ ev.new_value }}
+                </span>
+                <span class="tuning-actor" :class="{ 'is-human': ev.actor === 'human' }">
+                  {{ ev.actor === 'human' ? 'you' : 'Claude' }}
+                </span>
+                <span v-if="ev.created_at" class="tuning-when">{{ fmtDate(ev.created_at) }}</span>
+              </div>
+              <p class="tuning-reason">{{ ev.reason }}</p>
+            </li>
+          </ul>
+        </div>
+
         <!-- A design system belongs to a PROJECT, and the picker for it lives on
              the project. There was a setting here that designated the system
              this install's own interface was built from; it only ever described
@@ -3848,4 +4054,65 @@ async function deleteUser(userId: number) {
 .area-admin-form { display: flex; flex-direction: column; gap: 0.5rem; flex: 1; }
 .area-admin-create { margin-top: var(--fs-space-4); }
 .area-admin-actions { display: flex; gap: 0.4rem; }
+
+/* The retrieval tuning trail (#4102). Reads as a record, not a control panel:
+   the operator is reviewing what was done, and the reason is the part worth
+   reading, so it gets the full-width line under a compact header row. */
+.tuning-history {
+  margin-top: var(--fs-space-5);
+  padding-top: var(--fs-space-4);
+  border-top: 1px solid var(--fs-border-color);
+}
+.tuning-history-title {
+  margin: 0 0 var(--fs-space-2);
+  font-size: 0.95rem;
+  color: var(--fs-text-primary);
+}
+.tuning-list {
+  list-style: none;
+  margin: var(--fs-space-3) 0 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: var(--fs-space-2);
+}
+.tuning-item {
+  padding: var(--fs-space-3);
+  background: var(--fs-surface-raised);
+  border: 1px solid var(--fs-border-color);
+  border-radius: var(--fs-radius-md);
+}
+.tuning-item-head {
+  display: flex;
+  align-items: baseline;
+  flex-wrap: wrap;
+  gap: var(--fs-space-2);
+  font-size: 0.85rem;
+}
+.tuning-surface {
+  font-family: var(--fs-font-mono);
+  color: var(--fs-text-primary);
+}
+.tuning-dial,
+.tuning-move {
+  color: var(--fs-text-secondary);
+}
+.tuning-actor {
+  color: var(--fs-text-tertiary);
+  border: 1px solid var(--fs-border-color);
+  border-radius: var(--fs-radius-sm);
+  padding: 0 0.4rem;
+}
+/* The operator's own changes are marked, because "did I do this, or did the
+   session?" is the first question this list is asked. */
+.tuning-actor.is-human {
+  color: var(--fs-accent);
+  border-color: var(--fs-accent);
+}
+.tuning-when { margin-left: auto; color: var(--fs-text-tertiary); }
+.tuning-reason {
+  margin: var(--fs-space-2) 0 0;
+  font-size: 0.85rem;
+  color: var(--fs-text-secondary);
+}
 </style>

plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "scribe",
   "description": "Scribe for Claude Code: connects the scribe MCP server, adds the hooks that deliver live project state and relevant records at the right moment, ships the shared client-neutral Scribe skills (using-scribe, writing-plans, reporting-back, systematic-debugging, verification, brainstorming, reusing-code, shape-accounting), and syncs your saved Scribe Processes as skills (/scribe:sync).",
-  "version": "2026.09.16.2102",
+  "version": "2026.09.17.0111",
   "author": {
     "name": "Bryan Van Deusen"
   },

plugin/hooks/scribe_defs.sh

@@ -308,6 +308,50 @@ scribe_held_query() {
   return 0
 }
 
+# Drop EVERY per-session ledger, matched by convention rather than listed (#4101).
+#
+# A LIST IS THE BUG. Until now the compact/clear branch named its files one at
+# a time, and it named two of the five: `.rules.ids` and `.opened.ids` were
+# cleared while `.ids` (notes), `.sync.ids` (shape signals) and `.derive.ids`
+# survived. So milestone 386's defect — "a compaction destroys the context but
+# not the ledger, so the most applicable records become permanently
+# unreachable mid-session" — was fixed for rules and left standing on the note
+# and snippet surfaces, which are the ones that fire most often.
+#
+# Nobody decided that. The list was written when rules were the only ledger
+# that mattered and was never revisited when the others arrived, which is what
+# a hand-maintained list of "things to remember to clean up" does. Adding three
+# more `rm` lines would rebuild the same trap for the sixth ledger.
+#
+# So the rule is the NAME: a per-session ledger is `<sid>[.<kind>].ids`, and
+# everything matching that goes. A new ledger following the convention is
+# covered the day it is written, by nobody. One that does not follow it is a
+# deliberate exception and has to say so.
+#
+# Scoped to `.ids` rather than `<sid>.*` so a marker that is REWRITTEN on
+# compact rather than discarded can still live in these directories without
+# being swept away by a glob that was never told about it. `<sid>.unreached`
+# is the live example: it records that the instance could not be reached, not
+# what the session holds, and #2932 needs it to outlive a compaction.
+#
+# TWO DIRECTORIES, WHICH IS ITS OWN LESSON. The first cut of this swept only
+# `scribe-priorart` — every ledger named in the hooks was there, so the list
+# looked complete. `scribe_autoinject.sh` keeps its note ledger in
+# `scribe-autoinject`, so the arm that fires most (598 calls in five days) was
+# the one the clear could not reach, and the fix read as finished. Hence the
+# roster here rather than a path at the call site: one place to add to, and
+# the tests read THIS string rather than a copy of it.
+SCRIBE_LEDGER_DIRS="scribe-priorart scribe-autoinject"
+
+scribe_clear_session_ledgers() {
+  local sid="$1" dir
+  [ -n "$sid" ] || return 0
+  for dir in $SCRIBE_LEDGER_DIRS; do
+    rm -f "${TMPDIR:-/tmp}/$dir/$sid"*.ids 2>/dev/null || true
+  done
+  return 0
+}
+
 # ---------------------------------------------------------------------------
 # WHICH PROJECT IS THIS DIRECTORY'S? (#4085)
 #

plugin/hooks/scribe_session_context.sh

@@ -77,9 +77,11 @@ source=$(printf '%s' "$event" | jq -r '.source // empty' 2>/dev/null) || source=
 # this state are the ones that fire most often, which is to say the ones that
 # apply most.
 #
-# The session id survives a compaction — the etag marker further down is
-# rewritten on `compact` and keyed by session_id, which is only meaningful if
-# the id is stable — so the stale ledger is genuinely found again, not orphaned.
+# The session id survives a compaction — the ledgers are keyed by it and are
+# still found under the same name afterwards, so a stale ledger is genuinely
+# reached again rather than orphaned. (This used to point at an etag marker as
+# the evidence for that; milestone 394 removed the preload the etag described,
+# and `plugin_context.py` records its retirement.)
 #
 # CLEARED ON THE SOURCES THAT DESTROY CONTEXT, AND ONLY THOSE:
 #
@@ -93,25 +95,42 @@ source=$(printf '%s' "$event" | jq -r '.source // empty' 2>/dev/null) || source=
 #            fork carries the conversation, so if it inherits the id the ledger
 #            is accurate, and if it gets a new one the file is empty anyway.
 #
-# ONLY the rules ledger. The same directory holds .ids / .sync.ids /
-# .derive.ids for the note arms. Whether a surfaced NOTE should return after a
-# compaction is a different question with a different answer, and leaving those
-# alone is a decision rather than an oversight.
+# EVERY LEDGER, AND THE NOTE ARMS NEEDED IT MOST (#4101).
+#
+# This used to clear the two rule ledgers by name and say, in a comment, that
+# leaving `.ids` / `.sync.ids` / `.derive.ids` alone was "a decision rather than
+# an oversight". Reading the note arms says otherwise, on two counts:
+#
+#   - They are HARD exclusions. `exclude_ids` goes into `semantic_search_notes`
+#     itself, so a surfaced note is removed from the result set — it is not
+#     rendered as a reference the way #3750 made a repeated rule. There is no
+#     weaker form for it to fall back to.
+#   - They never AGE. #3751 gave the rules ledger a TTL precisely because
+#     salience decays without a context event; the note channels were left on a
+#     flat read.
+#
+# Hard plus permanent plus never cleared means a note surfaced in the first
+# minute of a session is unreachable for the rest of it, through any number of
+# compactions. That is milestone 386's original defect, alive on the arms that
+# fire most often, and nothing about it was decided.
+#
+# THE LIST WAS THE BUG, so the fix is not a longer list. `scribe_clear_session_
+# ledgers` matches on the naming convention — a per-session ledger is
+# `<sid>[.<kind>].ids` — which covers all five and covers the sixth on the day
+# it is written. Best-effort, like every other filesystem touch in these hooks:
+# a ledger that cannot be removed costs a repeated exclusion, never a session.
+#
+# NOT swept: `<sid>.unreached`, which records that the instance was unreachable
+# rather than what the session holds, and survives on purpose. The directories
+# swept are `scribe_defs.sh`'s `SCRIBE_LEDGER_DIRS` — plural, because the
+# auto-inject arm keeps its ledger somewhere else and a single-directory sweep
+# missed exactly the arm that fires most.
 case "$source" in
   compact|clear)
     sid=$(printf '%s' "$event" | jq -r '.session_id // empty' 2>/dev/null) || sid=""
     if [ -n "$sid" ]; then
       safe_sid=$(printf '%s' "$sid" | tr -c 'A-Za-z0-9._-' '_')
-      # Best-effort, like every other filesystem touch in these hooks: a ledger
-      # that cannot be removed costs a repeated exclusion, never a session.
-      rm -f "${TMPDIR:-/tmp}/scribe-priorart/${safe_sid}.rules.ids" 2>/dev/null || true
-      # BOTH ledgers, for one reason (#4100). `.opened.ids` records what the
-      # session read; a compaction is exactly the event that takes it away
-      # again. Clearing the naming ledger while keeping this one would leave
-      # the surfacing arms telling a freshly-summarised session "you opened
-      # it earlier" about a rule that is no longer anywhere in its context —
-      # a more confident version of the claim this milestone removed.
-      rm -f "${TMPDIR:-/tmp}/scribe-priorart/${safe_sid}.opened.ids" 2>/dev/null || true
+      scribe_clear_session_ledgers "$safe_sid"
     fi
     ;;
 esac

src/scribe/app.py

@@ -14,6 +14,7 @@ from scribe.routes.notes import notes_bp
 from scribe.routes.milestones import milestones_bp
 from scribe.routes.task_logs import task_logs_bp
 from scribe.routes.projects import projects_bp
+from scribe.routes.retrieval import retrieval_bp
 from scribe.routes.settings import settings_bp
 from scribe.routes.tasks import tasks_bp
 from scribe.routes.groups import groups_bp
@@ -79,6 +80,7 @@ def create_app() -> Quart:
     app.register_blueprint(milestones_bp)
     app.register_blueprint(notes_bp)
     app.register_blueprint(projects_bp)
+    app.register_blueprint(retrieval_bp)
     app.register_blueprint(settings_bp)
     app.register_blueprint(task_logs_bp)
     app.register_blueprint(tasks_bp)

src/scribe/mcp/server.py

@@ -131,6 +131,12 @@ _READ_ONLY_TOOLS = frozenset({
     # looked at names that had one (#3191). rule_history records a pull the way
     # the getters above do.
     "rules_due_for_verification", "rule_history",
+    # What each retrieval surface's floor and budget currently are, and what
+    # has been changed about them (#4102). Both pure reads; `tune_retrieval` is
+    # the write and is deliberately NOT here. Read access matters more than
+    # usual for these two: a session that cannot see the bar in force, or the
+    # reason it was last moved, is a session that will move it again blind.
+    "retrieval_surfaces", "retrieval_tuning_history",
 })
 
 # Every tool that WRITES, by name. Nothing reads this set at runtime — a tool
@@ -166,6 +172,9 @@ _WRITE_TOOLS = frozenset({
     "create_rule", "create_project_rule", "update_rule", "move_rule", "delete_rule",
     "create_preference", "update_preference",
     "relate_rules", "unrelate_rules", "mark_rule_verified",
+    # retrieval tuning — a write in both senses: it moves the number the arm
+    # reads, and it appends the reason to the audit trail (#4102).
+    "tune_retrieval",
     # trash
     "restore", "purge_trash",
 })

src/scribe/mcp/tools/__init__.py

@@ -5,14 +5,15 @@ to a FastMCP instance. `register_all(mcp)` is the single entry point called
 from `mcp.server.build_mcp_server`.
 """
 from scribe.mcp.tools import (
-    design_systems, milestones, notes, processes, projects, recent, repos, rulebooks, search, shapes,
-    snippets, systems, tags, tasks, trash,
+    design_systems, milestones, notes, processes, projects, recent, repos, retrieval_tuning,
+    rulebooks, search, shapes, snippets, systems, tags, tasks, trash,
 )
 
 
 def register_all(mcp) -> None:
     """Register every tool module's tools on the given FastMCP instance."""
     search.register(mcp)
+    retrieval_tuning.register(mcp)
     notes.register(mcp)
     tasks.register(mcp)
     projects.register(mcp)

src/scribe/mcp/tools/retrieval_tuning.py

@@ -0,0 +1,115 @@
+"""Reading and moving a retrieval surface's floor and budget (#4102).
+
+The write half of the loop `retrieval_telemetry` opens. That tool says what a
+bar did; these say what the bar IS, and let it be changed with the argument
+attached.
+"""
+from scribe.mcp._context import current_user_id
+from scribe.services import retrieval_tuning as tuning_svc
+
+
+async def retrieval_surfaces() -> dict:
+    """Every retrieval surface Scribe pushes on, with its floor and its budget.
+
+    Read this before changing either, and read it beside
+    `retrieval_telemetry(days=…, near_miss_samples=5)` — this tool says what is
+    in force, that one says what it did.
+
+    Each surface carries what it ASKS, what corpus it asks OVER, and how often
+    it FIRES, because a floor cannot be moved sensibly without all three. An arm
+    firing before every Bash call is spending attention on a scale an arm firing
+    once a turn is not, and the same number means different things to a query
+    that is a shell command, a code payload, or an operator's sentence.
+
+    `floor` is a COST floor: is this worth ranking at all. It is not a relevance
+    judgement — relevance is decided by the reader, which is the only
+    participant that can read a record's trigger against the actual situation,
+    and every injected line says so out loud ("read it before deciding it does
+    not apply").
+
+    `budget` is what actually binds. It is how many lines this surface may spend
+    on one injection, and it is the control to reach for when a surface feels
+    noisy — lowering a budget removes the weakest candidates, while raising a
+    floor removes whichever candidates happen to sit under a number.
+
+    `last_change` carries the reason last given for each dial, or is absent when
+    the surface is still on its shipped starting point. Those starting points
+    are starting points: they were measured against one corpus with one
+    embedding model and cannot be right for another install by construction.
+    That is why this tool exists rather than a better set of defaults.
+    """
+    return {"surfaces": await tuning_svc.current_settings(current_user_id())}
+
+
+async def tune_retrieval(
+    surface: str, dial: str, value: float, reason: str, actor: str = "model",
+) -> dict:
+    """Move one surface's floor or budget, recording why.
+
+    DO NOT CALL THIS FROM A PERCENTILE ALONE. `retrieval_telemetry` gives
+    `near_misses.p90` — the mass sitting just under the bar — and that number
+    says nothing about whether the mass is RELEVANT. The two have been measured
+    disagreeing: one surface logged 69 consecutive declines with the refused
+    record 0.0006 under its bar, and every percentile said "lower it". The
+    refused record turned out to be a rule about interpreting a REQUEST, matched
+    against a query about report layout — a false positive. Lowering would have
+    attached that rule to every completion report ever written. The statistic
+    and the correct action pointed in opposite directions, and only opening the
+    record could tell.
+
+    So the procedure is: `retrieval_telemetry(near_miss_samples=5)`, then
+    `get_rule` / `get_note` the `record_id`s it names, and decide whether those
+    records SHOULD have surfaced for those queries. Then move the dial, and say
+    in `reason` what you read and what it showed.
+
+    `reason` is required and must be substantive. It is the guardrail, not
+    bookkeeping: it is what lets the operator review a change they did not make,
+    disagree with it, and revert it. A number that moved with no stated basis is
+    one nobody can audit — including you, next week.
+
+    WHICH DIAL. Reach for `budget` when the complaint is volume, and `floor`
+    when the complaint is quality. Raising a floor to quieten a surface throws
+    away its best candidates along with its worst, because a floor cannot tell
+    rank from relevance; lowering a budget keeps the top of the ranking and
+    drops the tail, which is usually what was wanted.
+
+    Args:
+        surface: the surface name from `retrieval_surfaces` — also its
+            `retrieval_telemetry` source, so the two always name the same arm.
+        dial: "floor" or "budget".
+        value: the new value. A floor is clamped to [0, 1], a budget to a whole
+            number in [1, 10]. The result says whether a clamp bit, which
+            matters: believing you set a value the registry corrected means
+            reading the next telemetry as evidence about a bar never in force.
+        reason: what you read and what it showed. Required.
+        actor: "model" (default) or "human" — pass "human" only when relaying a
+            value the operator chose themselves, so the audit trail can tell
+            a change they made from one made on their behalf.
+    """
+    return await tuning_svc.set_dial(
+        current_user_id(), surface, dial, value, reason=reason, actor=actor,
+    )
+
+
+async def retrieval_tuning_history(surface: str = "", limit: int = 20) -> dict:
+    """What has been changed about retrieval on this install, newest first.
+
+    Reach for it before moving a dial that has been moved before — the previous
+    reason is the argument the next change has to answer, and a surface that has
+    been walked up and down repeatedly is evidence the floor is not the problem.
+
+    Args:
+        surface: restrict to one surface; omit for everything.
+        limit: how many events, default 20, capped at 200.
+    """
+    return {
+        "events": await tuning_svc.tuning_history(
+            current_user_id(), surface=surface or None, limit=limit,
+        )
+    }
+
+
+def register(mcp) -> None:
+    mcp.tool(name="retrieval_surfaces")(retrieval_surfaces)
+    mcp.tool(name="tune_retrieval")(tune_retrieval)
+    mcp.tool(name="retrieval_tuning_history")(retrieval_tuning_history)

src/scribe/mcp/tools/search.py

@@ -209,11 +209,13 @@ async def retrieval_telemetry(
 ) -> dict:
     """What the retrieval telemetry says about YOUR surfaces, over a window.
 
-    The read half of the loop the ranker's thresholds are meant to be tuned
-    from (#2975). Reach for it before changing a similarity threshold, a top-k,
-    or deciding whether a reranker is worth building — the alternative is
-    hand-probing the live instance, which is how the last such decision had to
-    be made.
+    The read half of the tuning loop, whose write half is `tune_retrieval`
+    (#2975, #4102). Reach for it before moving any floor or budget, and read
+    the records it names rather than its percentiles alone: this readout has
+    been measured pointing the WRONG WAY — 69 consecutive declines where every
+    percentile said "lower the bar" and the refused record was a false positive
+    — so `near_miss_samples=5` and opening the ids it returns is the step that
+    separates a real miss from a bar doing its job.
 
     Three readouts, from the three tables built for them:
 

src/scribe/models/__init__.py

@@ -27,6 +27,7 @@ from scribe.models.password_reset import PasswordResetToken  # noqa: E402, F401
 from scribe.models.invitation import InvitationToken  # noqa: E402, F401
 from scribe.models.embedding import MilestoneEmbedding, NoteEmbedding, RuleEmbedding  # noqa: E402, F401
 from scribe.models.retrieval_log import RetrievalLog  # noqa: E402, F401
+from scribe.models.retrieval_tuning import RetrievalTuningEvent  # noqa: E402, F401
 from scribe.models.note_usage import NoteUsageEvent  # noqa: E402, F401
 from scribe.models.rule_usage import RuleUsageEvent  # noqa: E402, F401
 from scribe.models.project import Project  # noqa: E402, F401

src/scribe/models/retrieval_tuning.py

@@ -0,0 +1,97 @@
+from datetime import datetime, timezone
+
+from sqlalchemy import DateTime, Float, Index, Integer, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from scribe.models import Base
+
+
+class RetrievalTuningEvent(Base):
+    """One row per change to a retrieval surface's floor or budget (#4102).
+
+    WHY A TABLE AND NOT JUST THE SETTING
+
+    The setting holds the number. It cannot hold the argument, and from this
+    step onward the argument is the interesting part: the operator's decision is
+    that the model moves these values, *"9 times out of 10"*, without being
+    asked each time. Delegation like that is only safe if it leaves a trail the
+    operator can read afterwards — what changed, from what to what, and on what
+    evidence — and can disagree with.
+
+    So `reason` is not decoration and not optional. It is the guardrail: a model
+    that has to state why is a model that has to have looked, and a reason that
+    turns out to be wrong is a reason someone can point at. A bare number in a
+    settings row records that something moved and nothing about whether it
+    should have.
+
+    WHY `actor` IS NOT JUST `user_id`
+
+    Both a person and a model act as the same user — the MCP tools run under the
+    operator's own id — so the id cannot distinguish them. That distinction is
+    exactly what an operator scanning this table wants first: "did I do this, or
+    did the session?" A change the operator made themselves needs no review; one
+    made on their behalf might.
+
+    FK-FREE ON user_id, like `RetrievalLog` and `AppLog` above it: the history of
+    how a surface was tuned should outlive the account that tuned it, and a
+    deleted user must not cascade away the record of why a number is where it is.
+    """
+
+    __tablename__ = "retrieval_tuning_events"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    # Declared here rather than via CreatedAtMixin because the index below
+    # orders on `created_at.desc()`, which needs the column object in this class
+    # body — a mixin's column is not in scope there.
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
+    )
+    user_id: Mapped[int | None] = mapped_column(Integer, nullable=True)
+
+    # The surface's registry name, which is also its `retrieval_logs.source`.
+    # That identity is what lets a reader put a change next to what the change
+    # did; `tests/test_retrieval_surfaces.py` asserts it rather than trusting it.
+    surface: Mapped[str] = mapped_column(Text, nullable=False)
+
+    # "floor" or "budget". Text rather than an enum because rule 36 makes a new
+    # CHECK value a migration, and this is a young surface that may well grow a
+    # third tunable — a constraint bought nothing here except a future migration.
+    dial: Mapped[str] = mapped_column(Text, nullable=False)
+
+    # Both stored as float so one pair of columns serves both dials; a budget is
+    # a whole number and reads back as one. `old_value` is nullable because the
+    # first change to a surface has no stored predecessor — it moved off the
+    # shipped starting point, which is a different event from moving off a value
+    # somebody chose, and worth being able to tell apart.
+    old_value: Mapped[float | None] = mapped_column(Float, nullable=True)
+    new_value: Mapped[float] = mapped_column(Float, nullable=False)
+
+    # "model" | "human". See the class docstring: the user id cannot tell these
+    # apart, and the difference is the first thing a reviewer wants.
+    actor: Mapped[str] = mapped_column(Text, nullable=False, default="model")
+
+    # REQUIRED at the service boundary, not merely non-null here. A column that
+    # is technically non-null is satisfied by "", which is how a required field
+    # becomes a formality; the service refuses a blank one.
+    reason: Mapped[str] = mapped_column(Text, nullable=False)
+
+    __table_args__ = (
+        # The only read this table has: one surface's history, newest first.
+        Index(
+            "ix_retrieval_tuning_surface_created",
+            "surface",
+            created_at.desc(),
+        ),
+    )
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "created_at": self.created_at.isoformat() if self.created_at else None,
+            "surface": self.surface,
+            "dial": self.dial,
+            "old_value": self.old_value,
+            "new_value": self.new_value,
+            "actor": self.actor,
+            "reason": self.reason,
+        }

src/scribe/routes/retrieval.py

@@ -0,0 +1,106 @@
+"""The operator's view of retrieval tuning — what the dials are, and who moved them (#4102).
+
+WHY THIS EXISTS SEPARATELY FROM /api/settings
+
+The numbers themselves are ordinary settings rows and could be written through
+the generic KV endpoint. They must not be, and that is the whole point of this
+blueprint: a floor changed through `/api/settings` moves silently, leaving the
+history saying nothing happened. From milestone 416 those dials are moved by
+the model on the operator's behalf, so a trail with holes in it is worse than
+no trail — it reads as complete.
+
+So every change to a retrieval dial goes through `set_dial`, from the UI as
+much as from the MCP tool, and the only difference is the `actor` recorded.
+"""
+import logging
+
+from quart import Blueprint, jsonify, request
+
+from scribe.auth import get_current_user_id, login_required
+from scribe.services.retrieval_tuning import set_dial, current_settings, tuning_history
+
+logger = logging.getLogger(__name__)
+
+retrieval_bp = Blueprint("retrieval", __name__, url_prefix="/api/retrieval")
+
+# What is recorded when the operator changes a dial in Settings and says
+# nothing about why.
+#
+# The MCP tool REFUSES a blank reason, and this endpoint does not, which is a
+# deliberate asymmetry rather than an oversight. The requirement exists to make
+# the model look at the records before it moves a number on someone else's
+# behalf. The operator IS that someone: they are the audience the trail is
+# written for, they cannot be uninformed about their own decision, and a
+# mandatory justification textarea on every control would be friction charged
+# to the one participant who owes no explanation (rule 24).
+#
+# The event is still written, because "the operator set this by hand" is the
+# single most useful thing the history can tell a later session — it is the one
+# entry the model must not quietly tune back.
+_OPERATOR_DEFAULT_REASON = "Set directly in Settings by the operator."
+
+
+@retrieval_bp.route("/surfaces", methods=["GET"])
+@login_required
+async def get_surfaces_route():
+    """Every tunable surface: its live floor and budget, what it asks and over
+    what, and the reason each dial was last moved."""
+    uid = get_current_user_id()
+    surfaces = await current_settings(uid)
+    return jsonify({"surfaces": surfaces, "total": len(surfaces)})
+
+
+@retrieval_bp.route("/surfaces/<surface>", methods=["PUT"])
+@login_required
+async def tune_surface_route(surface: str):
+    """Move one dial, recorded as a human change.
+
+    `actor` is fixed here rather than taken from the payload: this endpoint is
+    reached with a session cookie from the Settings form, so the actor is known
+    and accepting a claim about it would let the one field a reviewer relies on
+    be set to anything.
+    """
+    uid = get_current_user_id()
+    data = await request.get_json()
+    if not isinstance(data, dict):
+        return jsonify({"error": "Expected a JSON object"}), 400
+    if "dial" not in data or "value" not in data:
+        return jsonify({"error": "dial and value are required"}), 400
+
+    try:
+        value = float(data["value"])
+    except (TypeError, ValueError):
+        return jsonify({"error": f"value must be a number, got {data['value']!r}"}), 400
+
+    reason = str(data.get("reason") or "").strip() or _OPERATOR_DEFAULT_REASON
+    try:
+        result = await set_dial(
+            uid, surface, str(data["dial"]), value, reason=reason, actor="human",
+        )
+    except ValueError as e:
+        # Unknown surface, unknown dial — the service names the alternatives,
+        # so the message is worth passing through rather than flattening.
+        return jsonify({"error": str(e)}), 400
+    return jsonify(result)
+
+
+@retrieval_bp.route("/tuning-history", methods=["GET"])
+@login_required
+async def tuning_history_route():
+    """What has been changed about retrieval on this install, newest first.
+
+    The review surface. Unscoped by default because the operator's question
+    here is "what has been done on my behalf", not "why is this one arm set
+    like that" — the per-surface scoping is for the model.
+    """
+    uid = get_current_user_id()
+    surface = request.args.get("surface") or None
+    try:
+        limit = int(request.args.get("limit", 50))
+    except ValueError:
+        return jsonify({"error": "limit must be a whole number"}), 400
+    try:
+        events = await tuning_history(uid, surface=surface, limit=limit)
+    except ValueError as e:
+        return jsonify({"error": str(e)}), 400
+    return jsonify({"events": events, "total": len(events)})

src/scribe/routes/settings.py

@@ -9,6 +9,8 @@ from quart import Blueprint, jsonify, request
 
 from scribe.auth import login_required, get_current_user_id
 from scribe.config import Config
+from scribe.services.retrieval_surfaces import dial_for_key, get_surface
+from scribe.services.retrieval_tuning import set_dial
 from scribe.services.settings import (
     SECRET_MASK, delete_setting, get_all_settings, get_setting, set_settings_batch,
 )
@@ -25,6 +27,13 @@ settings_bp = Blueprint("settings", __name__, url_prefix="/api/settings")
 # (forge_token left with 0078: forge credentials are keyring rows now, #2778.)
 _SECRET_KEYS = frozenset({"smtp_password", "forge_webhook_secret"})
 
+# What the tuning history records for a dial changed through this form. The MCP
+# tool refuses a blank reason; the operator is not asked for one, because the
+# requirement exists to make the MODEL read the records before moving a number
+# on someone else's behalf — and the operator is that someone. See
+# routes/retrieval.py, which states the asymmetry in full.
+_SETTINGS_FORM_REASON = "Changed in Settings by the operator."
+
 
 def _masked(settings: dict) -> dict:
     return {
@@ -52,6 +61,33 @@ async def update_settings_route():
     to_save = {}
     for k, v in data.items():
         str_v = str(v)
+        # A retrieval dial is never written as a plain settings row, wherever
+        # the request came from (#4102). The value would land correctly and the
+        # tuning history would say nothing happened — and since milestone 416
+        # those dials are moved by the model on the operator's behalf, a
+        # history with holes in it is worse than none: it reads as complete.
+        #
+        # Routed rather than refused on purpose. Refusing would work only for
+        # callers that had been updated; this way every caller that ever writes
+        # one of these keys — this form, a script, an old client — leaves the
+        # trail, and there is no version of "forgot to use the other endpoint".
+        dial = dial_for_key(k)
+        if dial:
+            surface, which = dial
+            s = get_surface(surface)
+            # A CLEARED control means "back to the shipped starting point", and
+            # that is a change like any other — it is the operator reverting
+            # something, which is the single most important move this history
+            # can record. So it is written as an explicit set to the default
+            # rather than deleted, which would leave the same value behind and
+            # no record of anyone having chosen it.
+            default = s.floor_default if which == "floor" else s.budget_default
+            try:
+                await set_dial(uid, surface, which, float(str_v or default),
+                               reason=_SETTINGS_FORM_REASON, actor="human")
+            except (TypeError, ValueError) as e:
+                return jsonify({"error": f"{k}: {e}"}), 400
+            continue
         # A masked secret round-tripping through a client is "unchanged", not
         # a request to store the mask over the real credential.
         if k in _SECRET_KEYS and str_v == SECRET_MASK:

src/scribe/services/backup.py

@@ -13,6 +13,7 @@ from scribe.models.rule_version import RuleVersion
 from scribe.models.design_system import DesignSystem, DesignToken
 from scribe.models.note_usage import NoteUsageEvent
 from scribe.models.rule_usage import RuleUsageEvent
+from scribe.models.retrieval_tuning import RetrievalTuningEvent
 from scribe.models.canonical_system import CanonicalSystem
 from scribe.models.rulebook import RuleRelation, rule_systems as rule_systems_t
 from scribe.models.code_shape import CodeShape, CodeShapeEvent, CodeShapeUse
@@ -67,8 +68,14 @@ logger = logging.getLogger(__name__)
 # topic_suppressions with their tables (milestone 414): a rule's scope is its
 # home now. Older archives carrying those sections still restore — the keys are
 # simply not read — as do the subscribe_rulebooks inception choices they hold.
+# v16 (2026-09) added retrieval_tuning_events (milestone 416): the REASON each
+# retrieval floor and budget is where it is. `settings` already carried the
+# numbers, so leaving this behind would restore six moved dials with the
+# argument for them silently dropped — and from this step on those dials are
+# moved by the model, which is exactly the case where the operator needs the
+# argument to review.
 # Bump when the serialized schema changes.
-BACKUP_VERSION = 15
+BACKUP_VERSION = 16
 
 # Every table this backup carries, by its REAL name. Paired with _NOT_INCLUDED
 # below, these two lists must together account for the entire schema — which is
@@ -100,6 +107,12 @@ _BACKED_UP = [
     # accumulated, so a restore that dropped it would silently reset the
     # measurement to zero while everything still looked fine.
     "rule_usage_events",
+    # v16 (2026-09): why each retrieval floor and budget is where it is
+    # (milestone 416). The values live in `settings` and already travelled; the
+    # argument for them had nowhere to go. Now that the model moves these dials
+    # on the operator's behalf, a restore that kept the numbers and dropped the
+    # reasons would leave an install tuned by nobody it can name.
+    "retrieval_tuning_events",
 ]
 
 # Tables intentionally NOT in the backup, surfaced in the payload so the gap is
@@ -189,6 +202,9 @@ _COLUMN_EXCLUSIONS: dict[str, set[str]] = {
     "note_usage_events": {"id"},
     # Same as the note twin: the surrogate key is re-issued on insert.
     "rule_usage_events": {"id"},
+    # Same again — and everything else travels, because each remaining column
+    # is part of the argument: what moved, from what, to what, by whom, why.
+    "retrieval_tuning_events": {"id"},
     "design_systems": {"deleted_at", "deleted_batch_id", "created_at", "updated_at"},
     "design_tokens": {"deleted_at", "deleted_batch_id", "created_at", "updated_at"},
     "repo_bindings": {"id", "created_at", "updated_at"},
@@ -329,6 +345,25 @@ def _rule_usage_event_rows(rows) -> list[dict]:
     ]
 
 
+def _retrieval_tuning_event_rows(rows) -> list[dict]:
+    """The record of why a retrieval dial is where it is (#4102).
+
+    Not `to_dict()`: that method serves the MCP reader, which already knows
+    whose install it is asking about, so it omits `user_id`. A restore has to
+    remap it, and a row that arrived without it would have to be dropped or
+    guessed at.
+    """
+    return [
+        {
+            "user_id": r.user_id, "surface": r.surface, "dial": r.dial,
+            "old_value": r.old_value, "new_value": r.new_value,
+            "actor": r.actor, "reason": r.reason,
+            "created_at": r.created_at.isoformat() if r.created_at else None,
+        }
+        for r in rows
+    ]
+
+
 def _code_shape_rows(rows) -> list[dict]:
     return [r.to_dict() for r in rows]
 
@@ -617,6 +652,12 @@ async def export_full_backup() -> dict:
         rule_usage_events = (
             await session.execute(select(RuleUsageEvent))
         ).scalars().all()
+        # Oldest first, so a restored history reads in the order the dials
+        # actually moved — the sequence IS the argument when a surface has been
+        # walked up and down.
+        retrieval_tuning_events = (await session.execute(
+            select(RetrievalTuningEvent).order_by(RetrievalTuningEvent.id)
+        )).scalars().all()
         repo_bindings = (await session.execute(select(RepoBinding))).scalars().all()
         code_shapes = (await session.execute(select(CodeShape))).scalars().all()
         code_shape_events = (await session.execute(
@@ -661,6 +702,9 @@ async def export_full_backup() -> dict:
         "design_tokens": _design_token_rows(design_tokens),
         "note_usage_events": _usage_event_rows(usage_events),
         "rule_usage_events": _rule_usage_event_rows(rule_usage_events),
+        "retrieval_tuning_events": _retrieval_tuning_event_rows(
+            retrieval_tuning_events
+        ),
         "repo_bindings": _repo_binding_rows(repo_bindings),
         "note_supersessions": _note_supersession_rows(supersessions),
         "code_shapes": _code_shape_rows(code_shapes),
@@ -795,6 +839,15 @@ async def export_user_backup(user_id: int) -> dict:
         rule_usage_events = (await session.execute(
             select(RuleUsageEvent).where(RuleUsageEvent.rule_id.in_(_rule_ids))
         )).scalars().all() if _rule_ids else []
+        # Scoped on user_id, and here that IS the right column — unlike the
+        # rule usage events directly above. These record changes to this user's
+        # OWN retrieval settings, which is what `user_id` means on this table;
+        # there is no second owner to route around.
+        retrieval_tuning_events = (await session.execute(
+            select(RetrievalTuningEvent)
+            .where(RetrievalTuningEvent.user_id == user_id)
+            .order_by(RetrievalTuningEvent.id)
+        )).scalars().all()
         rule_relations = (await session.execute(
             select(RuleRelation).where(
                 RuleRelation.from_rule_id.in_(_rule_ids),
@@ -836,6 +889,9 @@ async def export_user_backup(user_id: int) -> dict:
         "design_tokens": _design_token_rows(design_tokens),
         "note_usage_events": _usage_event_rows(usage_events),
         "rule_usage_events": _rule_usage_event_rows(rule_usage_events),
+        "retrieval_tuning_events": _retrieval_tuning_event_rows(
+            retrieval_tuning_events
+        ),
         "repo_bindings": _repo_binding_rows(repo_bindings),
         "note_supersessions": _note_supersession_rows(supersessions),
         "code_shapes": _code_shape_rows(code_shapes),
@@ -975,6 +1031,7 @@ async def _restore_v2(data: dict) -> dict:
         "note_supersessions": 0, "code_shapes": 0, "code_shape_events": 0,
         "code_shape_uses": 0, "canonical_systems": 0,
         "rule_systems": 0, "rule_relations": 0, "rule_versions": 0,
+        "retrieval_tuning_events": 0,
     }
 
     async with async_session() as session:
@@ -1169,6 +1226,31 @@ async def _restore_v2(data: dict) -> dict:
             session.add(Setting(user_id=mapped_uid, key=s_data["key"], value=s_data.get("value", "")))
             stats["settings"] += 1
 
+        # 8b. Retrieval tuning history (v16) — restored beside the settings it
+        # explains, and for the same reason: the numbers above are the state,
+        # these rows are the argument for it. From milestone 416 those dials
+        # move on the operator's behalf, so an install restored with the values
+        # and without the reasons is one tuned by nobody it can name.
+        #
+        # No id remapping beyond the user: `surface` is a registry NAME, not a
+        # foreign key, which is what lets this history survive a restore into
+        # an install whose row ids all differ.
+        for t_data in data.get("retrieval_tuning_events", []):
+            mapped_uid = user_id_map.get(t_data.get("user_id") or 0)
+            if mapped_uid is None:
+                continue
+            session.add(RetrievalTuningEvent(
+                user_id=mapped_uid,
+                surface=t_data.get("surface", ""),
+                dial=t_data.get("dial", ""),
+                old_value=t_data.get("old_value"),
+                new_value=t_data.get("new_value"),
+                actor=t_data.get("actor") or "model",
+                reason=t_data.get("reason", ""),
+                created_at=_dt(t_data.get("created_at")),
+            ))
+            stats["retrieval_tuning_events"] += 1
+
         # 9. Rulebooks (v3)
         for rb_data in data.get("rulebooks", []):
             mapped_uid = user_id_map.get(rb_data.get("owner_user_id", 0))

src/scribe/services/plugin_context.py

@@ -31,6 +31,12 @@ from scribe.services.embeddings import semantic_search_notes, semantic_search_ru
 from scribe.services.note_usage import record_surfaced
 from scribe.services.rule_usage import record_rule_surfaced
 from scribe.services.supersession import superseded_ids
+from scribe.services.retrieval_surfaces import (
+    MAX_BUDGET,
+    SURFACES,
+    budget_for,
+    floor_for,
+)
 from scribe.services.retrieval_telemetry import record_retrieval
 from scribe.services.settings import get_setting
 
@@ -50,16 +56,25 @@ _GOAL_CHARS = 200
 # Per-user settings (keys live in the generic settings table). The threshold is
 # deliberately STRICTER than the pull-search default (embeddings
 # DEFAULT_SIMILARITY_THRESHOLD = 0.45): an unsolicited per-turn inject must clear
-# a higher bar than a search the agent chose to run. Defaults start conservative
-# and are meant to be tuned from retrieval_logs (source='auto_inject') once data
-# accrues — they're exposed in the Settings UI, no restart needed.
+# a higher bar than a search the agent chose to run.
+#
+# The defaults below are STARTING POINTS, and correcting them is the model's
+# job, not the operator's (#4102): `retrieval_surfaces` says what is in force,
+# `retrieval_telemetry(near_miss_samples=N)` says what it refused, and
+# `tune_retrieval` moves it with the reason attached. The operator can set any
+# of them in Settings and their change is recorded the same way — but nobody
+# has to read a log to get correct behaviour out of this.
 AUTOINJECT_ENABLED_KEY = "kb_autoinject_enabled"
-AUTOINJECT_THRESHOLD_KEY = "kb_autoinject_threshold"
-AUTOINJECT_TOP_K_KEY = "kb_autoinject_top_k"
+# The key and the value both live in the registry now (#4102); these names
+# survive because the comments above them are where each number's measurement
+# is recorded, and because the Settings UI agreement test pairs them with the
+# Vue refs by name. One definition, two readable places.
+AUTOINJECT_THRESHOLD_KEY = SURFACES["auto_inject"].floor_key
+AUTOINJECT_TOP_K_KEY = SURFACES["auto_inject"].budget_key
 
 AUTOINJECT_DEFAULT_ENABLED = True
-AUTOINJECT_DEFAULT_THRESHOLD = 0.55
-AUTOINJECT_DEFAULT_TOP_K = 3
+AUTOINJECT_DEFAULT_THRESHOLD = SURFACES["auto_inject"].floor_default
+AUTOINJECT_DEFAULT_TOP_K = SURFACES["auto_inject"].budget_default
 
 # The write-path trigger (#2082) gets its own on/off switch, its own threshold,
 # and shares only top-k. It originally shared the threshold too, on the argument
@@ -83,9 +98,9 @@ AUTOINJECT_DEFAULT_TOP_K = 3
 # pull-through (#2085) once a real corpus accrues; a cross-encoder rerank
 # (#1038) would subsume this bump.
 WRITEPATH_ENABLED_KEY = "kb_writepath_enabled"
-WRITEPATH_THRESHOLD_KEY = "kb_writepath_threshold"
+WRITEPATH_THRESHOLD_KEY = SURFACES["write_path"].floor_key
 WRITEPATH_DEFAULT_ENABLED = True
-WRITEPATH_DEFAULT_THRESHOLD = 0.68
+WRITEPATH_DEFAULT_THRESHOLD = SURFACES["write_path"].floor_default
 
 # The standing-rule arm (milestone 307) gets its own bar — the split #2223 made
 # one surface down, now made for the THIRD corpus. It inherited 0.68 above, and
@@ -133,8 +148,8 @@ WRITEPATH_DEFAULT_THRESHOLD = 0.68
 # case 0.72 was calibrated on, and the telemetry says it is working — the
 # write-path rule arm speaks on 37% of its calls and its refused mass sits at
 # p50 0.6989, comfortably under the bar rather than piled against it.
-RULEHINT_THRESHOLD_KEY = "kb_rulehint_threshold"
-RULEHINT_DEFAULT_THRESHOLD = 0.72
+RULEHINT_THRESHOLD_KEY = SURFACES["write_path_rule"].floor_key
+RULEHINT_DEFAULT_THRESHOLD = SURFACES["write_path_rule"].floor_default
 
 # THE COMMAND ARM'S OWN BAR, AND WHY IT IS NOT THE WRITE PATH'S (#3853).
 #
@@ -193,8 +208,8 @@ RULEHINT_DEFAULT_THRESHOLD = 0.72
 # eligible. Retrieval is ownership-scoped, not project-scoped. Scoping it
 # would drop that ceiling and widen the 0.0115, which is the larger fix and
 # the reason to settle project scoping before tuning this number twice.
-TOOLRULE_THRESHOLD_KEY = "kb_toolrule_threshold"
-TOOLRULE_DEFAULT_THRESHOLD = 0.68
+TOOLRULE_THRESHOLD_KEY = SURFACES["pre_tool_rule"].floor_key
+TOOLRULE_DEFAULT_THRESHOLD = SURFACES["pre_tool_rule"].floor_default
 
 # A SET OF RULES PER ACT, NOT THE SINGLE BEST ONE (#3851).
 #
@@ -223,7 +238,10 @@ TOOLRULE_DEFAULT_THRESHOLD = 0.68
 # and nothing else, so a moment with one clearly-relevant rule still shows
 # one, and a moment with four shows four. The corpus decides, not a constant.
 # The cap survives as a ceiling on the worst case, not as the usual answer.
-RULEHINT_LIMIT = 5
+# NOW A DEFAULT RATHER THAN A CAP (#4102): both rule act-arms read their own
+# budget from the registry, so this is the value an install starts at and not
+# the value it is stuck with. The reasoning below is why 5 is where it starts.
+RULEHINT_LIMIT = SURFACES["write_path_rule"].budget_default
 
 # MEASURED, NOT REASONED — and the reasoning it replaced was wrong (#3851).
 #
@@ -433,7 +451,11 @@ _CONCEPT_MIN_CHARS = 16
 _AUTOINJECT_BAND = 0.10
 # Hard ceiling on top-k regardless of the user's setting — this is an
 # awareness menu (titles only), never a content dump.
-_AUTOINJECT_MAX_TOP_K = 10
+# The budget ceiling, now shared by every surface rather than owned by this
+# one (#4102). It bounds the same thing everywhere — how many lines a single
+# unsolicited injection may occupy — so one surface having a private ceiling
+# was an accident of which arm got a configurable budget first.
+_AUTOINJECT_MAX_TOP_K = MAX_BUDGET
 
 # --- the prompt-boundary rule arm (#3852) ------------------------------------
 #
@@ -446,7 +468,7 @@ _AUTOINJECT_MAX_TOP_K = 10
 # The operator's message is the only query that exists before one is composed,
 # and this arm is what runs against it. Until now that hook searched notes
 # alone, so no rule had ever been retrieved against a thing the operator said.
-PROMPTRULE_THRESHOLD_KEY = "kb_promptrule_threshold"
+PROMPTRULE_THRESHOLD_KEY = SURFACES["prompt_rule"].floor_key
 # INHERITED FROM THE ACT ARMS, AND NOT YET EARNED HERE. 0.72 was tuned against
 # code and shell commands. An operator's prose is a different query shape
 # against the same documents, and nothing yet says the two distributions line
@@ -458,7 +480,7 @@ PROMPTRULE_THRESHOLD_KEY = "kb_promptrule_threshold"
 # front of a corpus that binds. Every call is logged under `prompt_rule` from
 # the first deploy, so a few days of real traffic settles it — read
 # `near_miss_samples` (#3807) before moving this, not the percentile alone.
-PROMPTRULE_DEFAULT_THRESHOLD = 0.72
+PROMPTRULE_DEFAULT_THRESHOLD = SURFACES["prompt_rule"].floor_default
 
 # MORE THAN THE ACT ARMS' SINGLE SLOT, anchored on this hook's budget rather
 # than theirs. RULEHINT_LIMIT is 1 because that arm fires before EVERY Bash
@@ -469,7 +491,7 @@ PROMPTRULE_DEFAULT_THRESHOLD = 0.72
 # And a prompt genuinely contains more than one act. "Merge to main and then
 # start on X" is two, governed by different rules; k=1 cannot serve that case
 # at all, where the act arms never face it because a command is one thing.
-PROMPTRULE_LIMIT = 3
+PROMPTRULE_LIMIT = SURFACES["prompt_rule"].budget_default
 
 # THE COMPLETION-REPORT ARM'S OWN BAR (services/reply_preferences.py).
 #
@@ -487,8 +509,8 @@ PROMPTRULE_LIMIT = 3
 # Kept at the prose arm's starting value rather than tuned: the split is what
 # makes the two independently movable, and a default is a product decision
 # that this install's corpus cannot settle (rule 115).
-REPORTPREF_THRESHOLD_KEY = "kb_reportpref_threshold"
-REPORTPREF_DEFAULT_THRESHOLD = 0.72
+REPORTPREF_THRESHOLD_KEY = SURFACES["report_preference"].floor_key
+REPORTPREF_DEFAULT_THRESHOLD = SURFACES["report_preference"].floor_default
 
 
 def _slugify(text: str) -> str:
@@ -592,8 +614,17 @@ async def build_process_manifest(user_id: int) -> dict:
 async def get_autoinject_config(user_id: int) -> dict:
     """Resolve a user's auto-inject settings, falling back to the defaults.
 
-    Returns {"enabled": bool, "threshold": float, "top_k": int}, clamped to
-    sane ranges (threshold to [0,1]; top_k to [1, _AUTOINJECT_MAX_TOP_K]).
+    Returns {"enabled": bool, "threshold": float, "top_k": int}.
+
+    THE TWO NUMBERS COME FROM THE REGISTRY NOW (#4102). They used to be read and
+    clamped here, and identically again in `get_writepath_config`, and again in
+    three rule arms, and once more in `reply_preferences`. That was
+    tolerable while the values were shipped constants. It stops being tolerable
+    once a tool is expected to MOVE them, because a tuning surface cannot be
+    consistent across arms that each spell their configuration differently.
+
+    `enabled` stays here: it is this surface's own switch, not a tunable number,
+    and the registry deliberately holds only the pair a floor-tuner touches.
     """
     enabled_raw = await get_setting(
         user_id, AUTOINJECT_ENABLED_KEY,
@@ -601,21 +632,11 @@ async def get_autoinject_config(user_id: int) -> dict:
     )
     enabled = enabled_raw.strip().lower() in ("true", "1", "yes", "on")
 
-    try:
-        threshold = float(await get_setting(
-            user_id, AUTOINJECT_THRESHOLD_KEY, str(AUTOINJECT_DEFAULT_THRESHOLD)))
-    except (TypeError, ValueError):
-        threshold = AUTOINJECT_DEFAULT_THRESHOLD
-    threshold = min(1.0, max(0.0, threshold))
-
-    try:
-        top_k = int(float(await get_setting(
-            user_id, AUTOINJECT_TOP_K_KEY, str(AUTOINJECT_DEFAULT_TOP_K))))
-    except (TypeError, ValueError):
-        top_k = AUTOINJECT_DEFAULT_TOP_K
-    top_k = min(_AUTOINJECT_MAX_TOP_K, max(1, top_k))
-
-    return {"enabled": enabled, "threshold": threshold, "top_k": top_k}
+    return {
+        "enabled": enabled,
+        "threshold": await floor_for(user_id, "auto_inject"),
+        "top_k": await budget_for(user_id, "auto_inject"),
+    }
 
 
 def _record_kind(note) -> str:
@@ -644,7 +665,7 @@ async def _reserve_slot_for_reuse(
     cfg: dict,
     *,
     project_id: int | None,
-    exclude_ids: set[int],
+    already: set[int],
 ) -> list:
     """Guarantee the reuse-shaped kinds one slot, if one clears threshold (#2246).
 
@@ -671,16 +692,23 @@ async def _reserve_slot_for_reuse(
     top_k = cfg["top_k"]
     _t0 = time.perf_counter()
     _rep: dict = {}
+    # THE LEDGER IS NOT AN EXCLUSION HERE EITHER (#4101) — but what is already
+    # in `kept` still is, and the two are different claims. A record sitting in
+    # this call's own menu must not be shown twice in it; a record shown in an
+    # EARLIER call is exactly what the slot should be allowed to spend itself
+    # on, because a snippet that was relevant then and is relevant now is the
+    # reuse case rather than a duplicate of it.
     reuse = await semantic_search_notes(
         user_id, query,
         limit=1,
         threshold=cfg["threshold"],
         project_id=project_id,
-        exclude_ids=exclude_ids | {int(n.id) for _s, n in kept},
+        exclude_ids={int(n.id) for _s, n in kept},
         note_type=_REUSE_KINDS,
         scope="browse",
         report=_rep,
     )
+    fresh_reuse = [(s, n) for s, n in reuse if int(n.id) not in already]
     # A real semantic query competing for a menu slot — logged like the scored
     # arm it displaces. Before this, the hit it PUSHED OUT was in
     # retrieval_logs and the query that pushed it out was not, so the slot
@@ -689,16 +717,17 @@ async def _reserve_slot_for_reuse(
     record_retrieval(
         user_id=user_id, source="reuse_slot", query=query,
         threshold=cfg["threshold"], limit=1, project_id=project_id,
-        is_task=None, results=reuse,
+        is_task=None, results=fresh_reuse,
         best_available=_rep.get("best_available_score"),
         best_available_id=_rep.get("best_available_id"),
         searched=bool(_rep.get("searched", True)),
+        suppressed=len(reuse) - len(fresh_reuse),
         duration_ms=(time.perf_counter() - _t0) * 1000.0,
     )
     # Verify the kind rather than trusting the query that asked for it, and
-    # dedup on top of exclude_ids. This slot exists FOR reuse kinds — a slot
-    # silently spent on something else is worse than no slot, because the line
-    # is indistinguishable from one that earned its place on score.
+    # dedup against this call's own menu. This slot exists FOR reuse kinds — a
+    # slot silently spent on something else is worse than no slot, because the
+    # line is indistinguishable from one that earned its place on score.
     kept_ids = {int(n.id) for _s, n in kept}
     fresh = [
         (s, n) for s, n in reuse
@@ -726,7 +755,8 @@ async def build_autoinject_hint(
     The four anti-bloat gates (see the module + milestone-93 design):
       1. high-confidence threshold (stricter than pull) — set per-user;
       2. margin gate — keep only hits within _AUTOINJECT_BAND of the top score;
-      3. session dedup — caller passes already-injected ids as `exclude_ids`;
+      3. session marking — caller passes already-injected ids as `exclude_ids`
+         and they are rendered again with `[seen]`, never withheld (#4101);
       4. title-first payload — id + kind + title + score only, never bodies.
     Disabled, blank-query, or nothing-clears-the-gates all return empty context,
     so most turns inject nothing.
@@ -741,6 +771,24 @@ async def build_autoinject_hint(
     if not cfg["enabled"] or not q:
         return empty
 
+    # THE LEDGER LEAVES THE SEARCH (#4101). `exclude_ids` used to go into
+    # `semantic_search_notes` itself, so a record this session had already been
+    # shown was removed from the candidate set — which is #3750's defect, on the
+    # arm that fires most. Three things followed from it, none of them intended:
+    #
+    #   - the second time a note was the best answer, the session got SILENCE,
+    #     indistinguishable from "nothing matched";
+    #   - a compaction made that permanent, because the ledger outlived the
+    #     context it described (fixed one layer down in this same step);
+    #   - and the score the search reported was measured against a candidate set
+    #     the caller had already edited, so `best_available` could name a bar
+    #     that turned nothing away (#3739).
+    #
+    # Now the ledger is a RENDERING fact, not a retrieval one: every repeat is
+    # still ranked, still shown, and carries a marker saying it was surfaced
+    # before. A note line is a title and a score — the repeat costs about as
+    # much as the comma in this sentence — so there is nothing here to save.
+    already = {int(i) for i in (exclude_ids or [])}
     t0 = time.perf_counter()
     _rep_ai: dict = {}
     hits = await semantic_search_notes(
@@ -748,7 +796,6 @@ async def build_autoinject_hint(
         limit=cfg["top_k"],
         threshold=cfg["threshold"],
         project_id=(project_id or None),
-        exclude_ids=set(exclude_ids or []),
         # Injection is the one retrieval nobody asked for, so it takes the BROWSE
         # scope: never a record shared one-to-one with the operator. What can
         # still appear is a collaborator's note inside a shared project — legible
@@ -756,24 +803,37 @@ async def build_autoinject_hint(
         scope="browse",
         report=_rep_ai,
     )
+    # `results=fresh` and `suppressed` together, on the rule arms' contract
+    # (#3752): a rendered repeat is not a new surfacing, so it stays out of the
+    # row's result set and is COUNTED instead. That keeps this source's surfaced
+    # set identical to its own log row (#3668) while making a zero-result call
+    # readable — `result_count == 0` with `suppressed_count > 0` is "everything
+    # that matched, this session has already seen", which is a different fact
+    # about the bar from "nothing cleared it" and used to be unreportable here.
+    fresh = [(s, n) for s, n in hits if int(n.id) not in already]
     record_retrieval(
         user_id=user_id, source="auto_inject", query=q,
         threshold=cfg["threshold"], limit=cfg["top_k"],
-        project_id=(project_id or None), is_task=None, results=hits,
+        project_id=(project_id or None), is_task=None, results=fresh,
         best_available=_rep_ai.get("best_available_score"),
         best_available_id=_rep_ai.get("best_available_id"),
         searched=bool(_rep_ai.get("searched", True)),
+        suppressed=len(hits) - len(fresh),
         duration_ms=(time.perf_counter() - t0) * 1000.0,
     )
     if not hits:
         return empty
 
-    # Margin gate: keep only hits close to the strongest one.
+    # Margin gate: keep only hits close to the strongest one. Computed over ALL
+    # hits, repeats included — the band measures distance from the top SCORE,
+    # and letting the ledger move that cutoff would make "you were shown this"
+    # change what counts as relevant, which is the axis independence the rule
+    # band keeps for the same reason.
     top_score = hits[0][0]
     kept = [(s, n) for s, n in hits if s >= top_score - _AUTOINJECT_BAND]
     kept = await _reserve_slot_for_reuse(
         user_id, q, kept, cfg, project_id=(project_id or None),
-        exclude_ids=set(exclude_ids or []),
+        already=already,
     )
 
     # A collaborator's note can reach this menu via a shared project, and the
@@ -786,10 +846,15 @@ async def build_autoinject_hint(
     # "records", not "notes" — the menu can hold snippets, processes and tasks
     # too, and the kind marker on each line is only legible if the header doesn't
     # already claim they're all one thing.
+    # "injected once per session" was true and is not any more (#4101): a repeat
+    # is shown again with a marker rather than withheld, so the header must stop
+    # promising the old contract. It now says what the marker means instead,
+    # once, rather than each repeated line having to explain itself.
     lines = [
         "> Possibly relevant from your Scribe records — open any in full with "
         "`get_note(id)`, or `get_snippet` / `get_process` for those kinds "
-        "(titles only; injected once per session):",
+        "(titles only; a line marked `seen` was surfaced earlier this session "
+        "and may no longer be in context):",
     ]
     # A superseded record is DEMOTED, not removed (#278) — so one can still reach
     # this menu, and when it does the reader has to be told. An agent handed
@@ -802,6 +867,13 @@ async def build_autoinject_hint(
         note_ids.append(int(note.id))
         title = (note.title or "(untitled)").replace("\n", " ").strip()
         line = f"> - #{note.id} [{_record_kind(note)}] \"{title}\" ({score:.2f})"
+        # ONE WORD, NOT A SENTENCE, and deliberately not the rule arms' phrasing.
+        # A rule line says "before deciding it does not apply", which is the
+        # voice of a record that BINDS; a note binds nothing, and borrowing that
+        # tone would tell the reader a dev-log has authority it does not have.
+        # The header carries the meaning, so the line carries only the flag.
+        if int(note.id) in already:
+            line += " [seen]"
         if int(note.id) in stale:
             line += " — SUPERSEDED, a later record covers this; check that first"
         if note.user_id != user_id:
@@ -813,7 +885,17 @@ async def build_autoinject_hint(
     # menu the agent actually saw. retrieval_logs already holds the full
     # candidate set for threshold tuning; conflating the two would make
     # "surfaced" mean two different things depending on the surface (#2085).
-    record_surfaced(user_id=user_id, note_ids=note_ids, source="auto_inject")
+    #
+    # FRESH ONLY, which is the same cut the log row above takes (#4101). A
+    # repeat is rendered but is not a new surfacing, and counting it again would
+    # make this table disagree with `retrieval_logs` about the same call —
+    # #3668's identity, which is the cheapest true statement available about
+    # this pair of tables and is not worth a marker's convenience.
+    record_surfaced(
+        user_id=user_id,
+        note_ids=[i for i in note_ids if i not in already],
+        source="auto_inject",
+    )
 
     return {"context": "\n".join(lines), "note_ids": note_ids, "config": cfg}
 
@@ -963,13 +1045,8 @@ async def build_prompt_rule_hint(
         return out
 
     try:
-        try:
-            threshold = float(await get_setting(
-                user_id, PROMPTRULE_THRESHOLD_KEY,
-                str(PROMPTRULE_DEFAULT_THRESHOLD)))
-        except (TypeError, ValueError):
-            threshold = PROMPTRULE_DEFAULT_THRESHOLD
-        threshold = min(1.0, max(0.0, threshold))
+        threshold = await floor_for(user_id, "prompt_rule")
+        limit = await budget_for(user_id, "prompt_rule")
 
         t0 = time.perf_counter()
         _rep: dict = {}
@@ -980,7 +1057,7 @@ async def build_prompt_rule_hint(
         # sessions — this surface speaks unasked, and a whole-rulebook answer
         # is only right for someone who asked the whole rulebook.
         hits = await semantic_search_rules(
-            user_id, q, limit=PROMPTRULE_LIMIT, threshold=threshold,
+            user_id, q, limit=limit, threshold=threshold,
             report=_rep, project_id=project_id or None,
         )
         duration_ms = (time.perf_counter() - t0) * 1000.0
@@ -996,7 +1073,7 @@ async def build_prompt_rule_hint(
         # and unverified for this corpus, so the zero rows are the point.
         record_retrieval(
             user_id=user_id, source="prompt_rule", query=q,
-            threshold=threshold, limit=PROMPTRULE_LIMIT,
+            threshold=threshold, limit=limit,
             project_id=project_id,
             is_task=None, results=fresh, duration_ms=duration_ms,
             best_available=_rep.get("best_available_score"),
@@ -1233,52 +1310,37 @@ def concept_query(code: str) -> str:
 
 
 async def get_writepath_config(user_id: int) -> dict:
-    """Write-path trigger settings: its own `enabled` and `threshold`, auto-inject's top_k.
+    """Write-path trigger settings — and the two rule arms' numbers alongside.
 
-    The threshold OVERRIDES the inherited auto-inject value — code embeddings
-    have a much higher similarity floor than prose, so the two surfaces need
-    different bars. See WRITEPATH_DEFAULT_THRESHOLD for the measurements (#2223).
-    top_k is still shared: "how many titles at once" means the same thing on
-    both surfaces, and nothing suggests they want different ceilings.
+    Three surfaces' worth of configuration arrives in one call because one hook
+    request drives all three arms. They are still three SURFACES with three
+    independent pairs, resolved from the registry (#4102).
+
+    The floors were split apart one at a time, each on its own measurement, and
+    those measurements are recorded where the defaults are: WRITEPATH (#2223 —
+    code embeddings sit on a much higher similarity floor than prose), RULEHINT
+    (a third corpus again), TOOLRULE (#3853 — a shell command is a different
+    query shape from a code payload and scores lower for the same relevance).
+
+    THE BUDGET IS NOW SPLIT TOO. `top_k` used to be auto-inject's outright, on
+    the argument that "how many titles at once" means the same thing on both
+    surfaces. It does not: this arm fires before every Write and Edit while
+    auto-inject fires once a turn, so the same number buys wildly different
+    amounts of attention. `write_path` inherits auto-inject's value when it has
+    none of its own, so no install that tuned the shared knob loses it.
     """
-    cfg = await get_autoinject_config(user_id)
     enabled_raw = await get_setting(
         user_id, WRITEPATH_ENABLED_KEY,
         "true" if WRITEPATH_DEFAULT_ENABLED else "false",
     )
-
-    try:
-        threshold = float(await get_setting(
-            user_id, WRITEPATH_THRESHOLD_KEY, str(WRITEPATH_DEFAULT_THRESHOLD)))
-    except (TypeError, ValueError):
-        threshold = WRITEPATH_DEFAULT_THRESHOLD
-    threshold = min(1.0, max(0.0, threshold))
-
-    try:
-        rule_threshold = float(await get_setting(
-            user_id, RULEHINT_THRESHOLD_KEY, str(RULEHINT_DEFAULT_THRESHOLD)))
-    except (TypeError, ValueError):
-        rule_threshold = RULEHINT_DEFAULT_THRESHOLD
-    rule_threshold = min(1.0, max(0.0, rule_threshold))
-
-    try:
-        tool_rule_threshold = float(await get_setting(
-            user_id, TOOLRULE_THRESHOLD_KEY, str(TOOLRULE_DEFAULT_THRESHOLD)))
-    except (TypeError, ValueError):
-        tool_rule_threshold = TOOLRULE_DEFAULT_THRESHOLD
-    tool_rule_threshold = min(1.0, max(0.0, tool_rule_threshold))
-
     return {
-        **cfg,
         "enabled": enabled_raw.strip().lower() in ("true", "1", "yes", "on"),
-        "threshold": threshold,
-        # Its own bar, for a third corpus — see RULEHINT_DEFAULT_THRESHOLD.
-        "rule_threshold": rule_threshold,
-        # And the COMMAND arm's own bar again, for the same reason one level
-        # down: a shell command is a different query shape from a code payload
-        # and scores lower for the same relevance (#3853). Separate keys, so an
-        # install can move one without the other — which is the whole finding.
-        "tool_rule_threshold": tool_rule_threshold,
+        "threshold": await floor_for(user_id, "write_path"),
+        "top_k": await budget_for(user_id, "write_path"),
+        "rule_threshold": await floor_for(user_id, "write_path_rule"),
+        "rule_top_k": await budget_for(user_id, "write_path_rule"),
+        "tool_rule_threshold": await floor_for(user_id, "pre_tool_rule"),
+        "tool_rule_top_k": await budget_for(user_id, "pre_tool_rule"),
     }
 
 def _rule_band(hits: list) -> list:
@@ -1468,12 +1530,16 @@ async def build_write_path_hint(
     #2707): the record gets corrected in the session that has the context,
     at the moment of change. Nearby and semantic hits stay the REUSE menu.
 
-    The two classes dedup on SEPARATE channels — `exclude_ids` (reuse) and
-    `exclude_sync_ids` (sync) — because they answer different questions: a
-    title shown as "consider reusing this" twenty turns ago must not silence
-    "you are editing the recorded file right now" (#2708).
+    The two classes track the session on SEPARATE channels — `exclude_ids`
+    (reuse) and `exclude_sync_ids` (sync) — because they answer different
+    questions: a title shown as "consider reusing this" twenty turns ago must
+    not silence "you are editing the recorded file right now" (#2708). The two
+    channels also now ACT differently, which is #4101: a reuse repeat is
+    rendered again with a `seen` marker, while the sync class still shows
+    once, because its claim is about an edit in progress rather than about a
+    record's continuing relevance and repeating it would be nagging.
 
-    Carries auto-inject's anti-bloat gates (margin, session dedup,
+    Carries auto-inject's anti-bloat gates (margin, session marking,
     titles-never-bodies) plus the shared top-k cap across ALL arms — so a file
     with a lot of recorded history can't turn one edit into a wall of text. Two
     gates are its OWN, because code is not prose: a stricter similarity
@@ -1546,7 +1612,13 @@ async def build_write_path_hint(
     # stay eligible here, which is the whole point of the split. Either way
     # they join `seen`, so the reuse arms (where the directory query would
     # surface them again) never re-list a record the sync block owns.
-    seen: set[int] = set(excluded)
+    #
+    # `seen` IS THIS CALL'S OWN MENU, and nothing else (#4101). It used to start
+    # from `excluded` — the session ledger — which folded two different claims
+    # into one variable: "already listed a few lines above" and "shown at some
+    # earlier point in the session". Only the first is a reason to stay quiet.
+    # The ledger is now a marker instead, on both reuse arms.
+    seen: set[int] = set()
     synced: list[dict] = []
     for item in here:
         nid = int(item["id"])
@@ -1560,7 +1632,12 @@ async def build_write_path_hint(
         if nid in seen:
             continue
         seen.add(nid)
-        placed.append(("nearby", item))
+        # MARKED HERE TOO, not just on the semantic arm, because these are one
+        # menu. A hint where some repeats carry `seen` and others are silently
+        # dropped — decided by which arm happened to find them — is worse than
+        # either rule applied consistently: the marker would read as a complete
+        # account of what the session has met before, and it would not be one.
+        placed.append(("nearby · seen" if nid in excluded else "nearby", item))
 
     # The stamping feed's "actually pulled it" half (#2791). Read once, before
     # the semantic arm, because the arm's query doubles as the resemblance
@@ -1592,16 +1669,19 @@ async def build_write_path_hint(
         query = concept_query(query) or query
     if remaining > 0 and query:
         t0 = time.perf_counter()
-        # Pulled-and-seen ids stay in the query (as evidence) but never in
-        # the menu — the dedup contract holds, the resemblance still lands.
-        pulled_seen = seen & set(pulled)
+        # Pulled-and-already-listed ids stay in the query (as evidence for
+        # `resembles`) but never in the menu, so the limit has to cover them.
+        # `seen` is this call's own menu now, which is the only thing left that
+        # is a reason to withhold (#4101).
+        in_menu = seen
+        pulled_in_menu = in_menu & set(pulled)
         _rep_wp: dict = {}
         hits = await semantic_search_notes(
             user_id, query,
-            limit=remaining + len(pulled_seen),
+            limit=remaining + len(pulled_in_menu),
             threshold=cfg["threshold"],
             project_id=scope_project,
-            exclude_ids=seen - pulled_seen,
+            exclude_ids=in_menu - set(pulled),
             # Snippets AND recorded experience (#2246). This arm was
             # snippets-only, which is auto-inject's mistake inverted: an issue
             # saying "we tried this and it deadlocked", or a dev-log recording
@@ -1625,41 +1705,50 @@ async def build_write_path_hint(
             int(note.id): float(score) for score, note in hits
             if int(note.id) in pulled
         }
-        shown = [(s, n) for s, n in hits if int(n.id) not in seen]
+        shown = [(s, n) for s, n in hits if int(n.id) not in in_menu]
         # WHAT THIS ARM WITHHELD AFTER THE SEARCH ANSWERED, and the reason
         # `best_available_score` cannot always be reported here (#3739 again,
         # from the side its fix did not reach).
         #
         # This arm is the one note arm that filters TWICE. `exclude_ids` takes
-        # `seen - pulled_seen` into the search, but the pulled-and-seen ids stay
-        # in the query deliberately — `resembles` above needs them — and are
-        # dropped in the line above instead. So the score the search reported is
-        # PRE that drop while the row's `result_count` is POST it, and a record
-        # the session had already been shown could be logged as something the
-        # BAR turned away. Live proof on the first read after #3739 shipped:
-        # write_path's near-miss max was 0.822 while the lowest score it ever
-        # RETURNED was 0.6857 — a "rejection" that beat every acceptance.
-        #
-        # The suppression column cannot rescue it the way it does for the rule
-        # arms: this arm's count would be PARTIAL, covering only the drops made
-        # here and not the ones `exclude_ids` made inside the search, and a
-        # partial number under a name that reads as complete is the substitution
-        # this whole milestone exists to stop.
+        # the already-listed ids into the search, but the PULLED ones among them
+        # stay in the query deliberately — `resembles` above needs them — and
+        # are dropped in the line above instead. So the score the search
+        # reported is PRE that drop while the row's `result_count` is POST it,
+        # and a record already listed in this same menu could be logged as
+        # something the BAR turned away. Live proof on the first read after
+        # #3739 shipped: write_path's near-miss max was 0.822 while the lowest
+        # score it ever RETURNED was 0.6857 — a "rejection" that beat every
+        # acceptance.
         #
         # So the honest answer is null — "not measured on this call" — whenever
         # this filter removed anything, because then the bar is not the only
         # thing that turned something away and the reported score may belong to
         # a record we withheld ourselves. Calls where nothing was dropped keep
         # reporting it, which is most of them.
+        #
+        # THE LEDGER IS NO LONGER PART OF THIS (#4101), and that is why the
+        # suppression column can now be filled in where it could not before.
+        # The old objection was that a count here would be PARTIAL — covering
+        # the drops made in this function but not the ones `exclude_ids` made
+        # inside the search — and a partial number under a name that reads as
+        # complete is the substitution this milestone exists to stop. That was
+        # right while the ledger was one of the things `exclude_ids` carried.
+        # It no longer is: every ledger repeat comes back from the search and is
+        # rendered, so `suppressed` counts all of them and none are hidden
+        # inside the query. What `exclude_ids` still removes is this call's own
+        # menu, which is not suppression at all — those records ARE being shown,
+        # one block further up.
         withheld_here = len(hits) - len(shown)
         hits = shown[:remaining]
+        fresh = [(s, n) for s, n in hits if int(n.id) not in excluded]
         record_retrieval(
             user_id=user_id, source="write_path", query=query,
             threshold=cfg["threshold"], limit=remaining,
             # is_task is None, not False: this arm now returns issues too, and
             # recording it as a notes-only retrieval would misdescribe the
             # candidate set the threshold is being tuned against.
-            project_id=scope_project, is_task=None, results=hits,
+            project_id=scope_project, is_task=None, results=fresh,
             best_available=(
                 None if withheld_here else _rep_wp.get("best_available_score")
             ),
@@ -1670,6 +1759,7 @@ async def build_write_path_hint(
                 None if withheld_here else _rep_wp.get("best_available_id")
             ),
             searched=bool(_rep_wp.get("searched", True)),
+            suppressed=len(hits) - len(fresh),
             duration_ms=(time.perf_counter() - t0) * 1000.0,
         )
         if hits:
@@ -1683,9 +1773,19 @@ async def build_write_path_hint(
                 # and an unlabelled line would be read as "here is code to
                 # reuse", which is the opposite of what it says.
                 kind = _record_kind(note)
-                scored.append((
+                marker = (
                     f"similar {score:.2f}" if kind == "snippet"
-                    else f"similar {score:.2f} · {kind}",
+                    else f"similar {score:.2f} · {kind}"
+                )
+                # The repeat marker rides the same dotted list as the kind, so a
+                # reference costs four characters and needs no second line
+                # (#4101). Same word as the auto-inject menu deliberately: a
+                # reader meeting `seen` on two different surfaces should not
+                # have to work out whether they mean the same thing.
+                if int(note.id) in excluded:
+                    marker += " · seen"
+                scored.append((
+                    marker,
                     {
                         "id": int(note.id), "title": note.title, "user_id": note.user_id,
                         # Carried so the line can disclose a cross-language hit
@@ -1811,7 +1911,8 @@ async def build_write_path_hint(
             "`get_snippet(id)` for a snippet, `get_task(id)` for an issue, "
             "`get_note(id)` otherwise. Reuse a snippet rather than writing a fresh "
             "one-off; read an issue before repeating what it records "
-            "(titles only; shown once per session):"
+            "(titles only; a line marked `seen` was surfaced earlier this "
+            "session and may no longer be in context):"
         )
     # Say what a language tag MEANS, and only when one is actually on the menu.
     # Without this the reader has to infer why "· python" is attached to a hit on
@@ -1848,7 +1949,13 @@ async def build_write_path_hint(
     if sync_note_ids:
         by_arm["write_path_sync"] = list(sync_note_ids)
     for marker, item in menu:
-        arm = "write_path_place" if marker == "nearby" else "write_path_semantic"
+        # A rendered repeat is not a new surfacing (#4101) — same cut the log
+        # row takes, so this table and `retrieval_logs` keep agreeing about the
+        # same call (#3668).
+        if int(item["id"]) in excluded:
+            continue
+        arm = ("write_path_place" if marker.startswith("nearby")
+               else "write_path_semantic")
         by_arm.setdefault(arm, []).append(int(item["id"]))
     for arm, ids in by_arm.items():
         record_surfaced(user_id=user_id, note_ids=ids, source=arm)
@@ -1882,7 +1989,7 @@ async def build_write_path_hint(
         rule_t0 = time.perf_counter()
         _rep_wpr: dict = {}
         hits = await semantic_search_rules(
-            user_id, code or path, limit=RULEHINT_LIMIT,
+            user_id, code or path, limit=cfg["rule_top_k"],
             threshold=cfg["rule_threshold"],
             report=_rep_wpr, project_id=project_id or None,
         )
@@ -1943,7 +2050,7 @@ async def build_write_path_hint(
         # the same readout.
         record_retrieval(
             user_id=user_id, source="write_path_rule", query=code or path,
-            threshold=cfg["rule_threshold"], limit=RULEHINT_LIMIT,
+            threshold=cfg["rule_threshold"], limit=cfg["rule_top_k"],
             project_id=project_id,
             is_task=None, results=fresh, duration_ms=rule_ms,
             best_available=_rep_wpr.get("best_available_score"),
@@ -2039,7 +2146,7 @@ async def build_tool_rule_hint(
         t0 = time.perf_counter()
         _rep_ptr: dict = {}
         hits = await semantic_search_rules(
-            user_id, query, limit=RULEHINT_LIMIT,
+            user_id, query, limit=cfg["tool_rule_top_k"],
             threshold=cfg["tool_rule_threshold"],
             report=_rep_ptr, project_id=project_id or None,
         )
@@ -2062,7 +2169,7 @@ async def build_tool_rule_hint(
         # failure the arm was built to stop.
         record_retrieval(
             user_id=user_id, source="pre_tool_rule", query=query,
-            threshold=cfg["tool_rule_threshold"], limit=RULEHINT_LIMIT,
+            threshold=cfg["tool_rule_threshold"], limit=cfg["tool_rule_top_k"],
             project_id=project_id,
             is_task=None, results=fresh, duration_ms=duration_ms,
             best_available=_rep_ptr.get("best_available_score"),

src/scribe/services/reply_preferences.py

@@ -61,13 +61,9 @@ import logging
 import time
 
 from scribe.services.embeddings import semantic_search_rules
-from scribe.services.plugin_context import (
-    REPORTPREF_DEFAULT_THRESHOLD,
-    REPORTPREF_THRESHOLD_KEY,
-)
+from scribe.services.retrieval_surfaces import SURFACES, budget_for, floor_for
 from scribe.services.retrieval_telemetry import record_retrieval
 from scribe.services.rule_usage import record_rule_surfaced
-from scribe.services.settings import get_setting
 
 logger = logging.getLogger(__name__)
 
@@ -85,16 +81,20 @@ COMPLETION_QUERY = (
 # A handful, not a menu. More than a few shape preferences for ONE kind of
 # reply would contradict each other before they helped; the limit is here to
 # keep one noisy corpus from turning a status change into a wall of text.
-LIMIT = 3
+# The STARTING budget, not the budget (#4102). Both numbers this arm runs on
+# now come from the surface registry, so the model that reads this arm's
+# telemetry can move either — which matters more here than anywhere else,
+# because a fixed query makes this arm's score a constant and a floor a hair
+# above it produces a dead arm no amount of traffic will ever reveal.
+LIMIT = SURFACES["report_preference"].budget_default
 
 
 async def _threshold(user_id: int) -> float:
-    try:
-        value = float(await get_setting(
-            user_id, REPORTPREF_THRESHOLD_KEY, str(REPORTPREF_DEFAULT_THRESHOLD)))
-    except (TypeError, ValueError):
-        value = REPORTPREF_DEFAULT_THRESHOLD
-    return min(1.0, max(0.0, value))
+    return await floor_for(user_id, SOURCE)
+
+
+async def _limit(user_id: int) -> int:
+    return await budget_for(user_id, SOURCE)
 
 
 async def completion_preferences(user_id: int, *, project_id: int | None = None) -> list[dict]:
@@ -115,16 +115,17 @@ async def completion_preferences(user_id: int, *, project_id: int | None = None)
     """
     try:
         threshold = await _threshold(user_id)
+        limit = await _limit(user_id)
         report: dict = {}
         t0 = time.perf_counter()
         hits = await semantic_search_rules(
-            user_id, COMPLETION_QUERY, limit=LIMIT, threshold=threshold,
+            user_id, COMPLETION_QUERY, limit=limit, threshold=threshold,
             kind="preference", report=report, project_id=project_id,
         )
         hits = [(score, rule) for score, rule in hits if rule.kind == "preference"]
         record_retrieval(
             user_id=user_id, source=SOURCE, query=COMPLETION_QUERY,
-            threshold=threshold, limit=LIMIT, project_id=project_id,
+            threshold=threshold, limit=limit, project_id=project_id,
             is_task=None, results=hits,
             best_available=report.get("best_available_score"),
             best_available_id=report.get("best_available_id"),

src/scribe/services/retrieval_surfaces.py

@@ -0,0 +1,264 @@
+"""One registry of the retrieval surfaces, and the two numbers each one has (#4102).
+
+WHY THIS EXISTS
+
+Six push arms each carried their own loose copy of the same shape: a settings
+key, a default, and a limit that was usually a module constant nobody could
+change. The read-and-clamp was written out separately in `plugin_context` (twice
+over, for auto-inject and the write path), in three rule arms, and again as
+`reply_preferences._threshold`. That was survivable while the numbers were
+shipped constants an operator occasionally edited.
+
+It stops being survivable once the numbers are meant to MOVE. The operator's
+decision for this step:
+
+    "the floor should be chosen and adjusted by the model using it. we've come
+    back to something either fails or has to be looked at by the user we need a
+    model consistent surface for the adjustment of these floor values. the user
+    should be able to touch it but the model should be the thing handling it 9
+    times out of 10."
+
+A tuning surface cannot be "model consistent" if every arm spells its own
+configuration differently. So the arms stop owning their numbers and read them
+from here instead, and the tuning tool, the routes and the Settings UI all
+enumerate THIS table rather than hard-coding six special cases.
+
+WHAT A FLOOR IS NOW, AND WHAT IT IS NOT
+
+It is not a relevance judgement. Relevance is decided by the reader, which is
+the only participant that can read a trigger against a situation — that is the
+milestone's whole argument, and the injected line has always said so out loud
+("read it before deciding it does not apply").
+
+A floor answers the cheaper question: *is this worth ranking at all*. `k` is
+what binds, and `k` is a BUDGET — how much of this surface's attention a
+candidate list may spend. An arm that fires before every Bash call cannot
+afford what an arm that fires once a turn can.
+
+WHY THE DEFAULTS BELOW ARE STARTING POINTS AND NOT ANSWERS
+
+A cosine score is a distance in BAAI/bge-small-en-v1.5's vector space, measured
+against THIS corpus. It cannot transfer to an install with different records,
+and rule 115 forbids defending a shipped default from this instance's
+telemetry — which is what made the old design unbuildable: every number was a
+guess everywhere except here, and there was no mechanism that could ever
+improve it.
+
+The mechanism is the fix. Scribe ships a starting point and the means to
+correct it, so the values below carry the measurement that motivated them (see
+the long comments in `plugin_context.py`, which are kept where they are because
+they record how each number was first arrived at) without claiming to be right
+for anybody else.
+
+HOW A FLOOR SHOULD ACTUALLY BE MOVED
+
+By reading the records the floor refused — `retrieval_telemetry(
+near_miss_samples=N)` returns them by id — and never by the percentile alone.
+That is not a style preference; it is the one case where the two disagreed and
+was checked. `report_preference` logged 69 consecutive declines with the
+refused score 0.0006 under the bar, and every percentile said "lower it".
+Reading the refused record showed it was rule 77 "Extract intent from loose
+phrasing", a false positive, so lowering the bar would have delivered that rule
+on every completion report ever written. The statistic and the correct action
+pointed in opposite directions, and only opening the record could tell.
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from scribe.services.settings import get_setting
+
+# A budget nobody should be able to set past. Not a tuning value — a guard on
+# the worst case, so a mistyped setting cannot turn a menu into a wall of text.
+# Shared by every surface because it bounds the same thing everywhere: how many
+# lines a single unsolicited injection may occupy.
+MAX_BUDGET = 10
+
+
+@dataclass(frozen=True)
+class Surface:
+    """One push arm's tunable pair, plus enough prose to tune it responsibly.
+
+    `asks` / `over` / `fires` are not documentation for this file — they are
+    rendered by the tuning tool and the Settings UI. A floor cannot be moved
+    sensibly by anyone, model or human, who does not know what the query is, what
+    corpus it runs against, or how often it costs something. Those three facts
+    are exactly what separates these arms from each other, and they were
+    previously recoverable only by reading `plugin_context.py`.
+    """
+
+    name: str
+    """The telemetry `source` value, and the join key.
+
+    MUST equal the string this arm passes to `record_retrieval`. Everything
+    useful about tuning depends on that identity: the tool that moves a floor
+    and the table that says what the floor did have to be talking about the same
+    arm. A test asserts it rather than a comment asking nicely.
+    """
+
+    floor_key: str
+    floor_default: float
+    budget_key: str
+    budget_default: int
+    asks: str
+    over: str
+    fires: str
+    budget_falls_back_to: str = ""
+    """A budget key to inherit when this surface has none of its own set.
+
+    Only `write_path` uses it, and only because it USED to share auto-inject's
+    `top_k` outright. Giving it a key without this would silently reset the
+    budget of every install that had tuned the shared one — a behaviour change
+    delivered as a default, which is the shape of regression nobody reports
+    because nothing looks broken.
+    """
+
+
+SURFACES: dict[str, Surface] = {
+    "auto_inject": Surface(
+        name="auto_inject",
+        floor_key="kb_autoinject_threshold",
+        floor_default=0.55,
+        budget_key="kb_autoinject_top_k",
+        budget_default=3,
+        asks="the operator's message, as they typed it",
+        over="notes, snippets, processes and issues",
+        fires="once per operator turn",
+    ),
+    "write_path": Surface(
+        name="write_path",
+        floor_key="kb_writepath_threshold",
+        floor_default=0.68,
+        budget_key="kb_writepath_top_k",
+        budget_default=3,
+        budget_falls_back_to="kb_autoinject_top_k",
+        asks="the code being written, rewritten as a concept query",
+        over="snippets and recorded issues",
+        fires="before every Write and Edit",
+    ),
+    "write_path_rule": Surface(
+        name="write_path_rule",
+        floor_key="kb_rulehint_threshold",
+        floor_default=0.72,
+        budget_key="kb_rulehint_top_k",
+        budget_default=5,
+        asks="the code being written, against rule triggers",
+        over="global rules plus the bound project's own",
+        fires="before every Write and Edit",
+    ),
+    "pre_tool_rule": Surface(
+        name="pre_tool_rule",
+        floor_key="kb_toolrule_threshold",
+        floor_default=0.68,
+        budget_key="kb_toolrule_top_k",
+        budget_default=5,
+        asks="the command about to run, against rule triggers",
+        over="global rules plus the bound project's own",
+        fires="before every Bash call — the busiest arm there is",
+    ),
+    "prompt_rule": Surface(
+        name="prompt_rule",
+        floor_key="kb_promptrule_threshold",
+        floor_default=0.72,
+        budget_key="kb_promptrule_top_k",
+        budget_default=3,
+        asks="the operator's message, against rule triggers",
+        over="global rules plus the bound project's own",
+        fires="once per operator turn",
+    ),
+    "report_preference": Surface(
+        name="report_preference",
+        floor_key="kb_reportpref_threshold",
+        floor_default=0.72,
+        budget_key="kb_reportpref_top_k",
+        budget_default=3,
+        # THE ONE FIXED QUERY, and the reason this arm behaves unlike the rest.
+        # The others score something that varies per call; this one scores a
+        # constant string, so its top score for a given corpus is also a
+        # constant. A floor a hair above that constant is not a quiet arm, it is
+        # a dead one, and no amount of traffic will ever reveal it — which is
+        # precisely how this arm spent 69 calls declining the same record.
+        asks="a fixed question about how to lay out a completion report",
+        over="preferences",
+        fires="when a task finishes",
+    ),
+}
+
+# Reserved slots are deliberately absent. `preference_slot` and `reuse_slot`
+# borrow their parent arm's floor and are hard-limited to one hit each, because
+# their entire purpose is to guarantee a single line to a kind of record that
+# keeps losing a general score contest (#2246, #3894). A budget of "1" is the
+# feature; exposing it as tunable would invite setting it to 0 and silently
+# removing the guarantee.
+
+
+def surface_names() -> list[str]:
+    """Every tunable surface, in a stable order for menus and listings."""
+    return list(SURFACES)
+
+
+def get_surface(name: str) -> Surface:
+    """Look one up, refusing an unknown name loudly.
+
+    A typo'd surface must not be writable. Settings keys are free-form strings
+    in a generic table, so a tuning call naming `pretool_rule` would otherwise
+    write a key nothing ever reads — a change that appears to succeed, reports a
+    new value, and alters nothing.
+    """
+    try:
+        return SURFACES[name]
+    except KeyError:
+        raise ValueError(
+            f"unknown retrieval surface {name!r}. Tunable surfaces are: "
+            + ", ".join(surface_names())
+        ) from None
+
+
+def dial_for_key(key: str) -> tuple[str, str] | None:
+    """Which `(surface, dial)` a settings key belongs to, or None.
+
+    The registry read backwards, and it exists for one caller: the generic
+    `/api/settings` endpoint, which accepts any key at all. Without this, a
+    floor written through that endpoint moves with no event recorded, and the
+    tuning history says nothing happened — a trail with holes in it, which is
+    worse than no trail because it reads as complete.
+
+    Derived rather than listed so a seventh surface is covered the moment it is
+    added here, which is the only way this stays true.
+    """
+    for surface in SURFACES.values():
+        if key == surface.floor_key:
+            return (surface.name, "floor")
+        if key == surface.budget_key:
+            return (surface.name, "budget")
+    return None
+
+
+async def floor_for(user_id: int, name: str) -> float:
+    """This install's current floor for a surface, clamped to [0, 1]."""
+    s = get_surface(name)
+    try:
+        value = float(await get_setting(user_id, s.floor_key, str(s.floor_default)))
+    except (TypeError, ValueError):
+        value = s.floor_default
+    return min(1.0, max(0.0, value))
+
+
+async def budget_for(user_id: int, name: str) -> int:
+    """This install's current budget for a surface, clamped to [1, MAX_BUDGET].
+
+    The lower clamp is 1, never 0: a surface turned off is turned off by its
+    `enabled` switch, which says so. A budget of zero would be an arm that runs
+    a search, logs a retrieval, and renders nothing — indistinguishable in the
+    telemetry from a bar nothing cleared, which is the exact confusion this
+    milestone exists to remove.
+    """
+    s = get_surface(name)
+    raw = await get_setting(user_id, s.budget_key, "")
+    if not raw and s.budget_falls_back_to:
+        raw = await get_setting(user_id, s.budget_falls_back_to, "")
+    try:
+        value = int(float(raw)) if raw else s.budget_default
+    except (TypeError, ValueError):
+        value = s.budget_default
+    return min(MAX_BUDGET, max(1, value))

src/scribe/services/retrieval_tuning.py

@@ -0,0 +1,226 @@
+"""Moving a retrieval surface's floor or budget, with the argument attached (#4102).
+
+WHY THIS EXISTS
+
+The operator's decision for milestone 416 step 4:
+
+    "the floor should be chosen and adjusted by the model using it. we've come
+    back to something either fails or has to be looked at by the user we need a
+    model consistent surface for the adjustment of these floor values. the user
+    should be able to touch it but the model should be the thing handling it 9
+    times out of 10."
+
+`retrieval_surfaces` made the six arms describe their numbers the same way.
+This module is the write half: one call that moves one dial on one surface,
+records what it was, what it became, who moved it and why, and refuses to do
+any of that without a reason.
+
+WHY A REASON IS REQUIRED
+
+Because the alternative was tried and measured. The milestone originally listed
+self-tuning as a non-goal on the strength of one case: `report_preference`
+logged 69 consecutive declines with the refused record 0.0006 under the bar, and
+every percentile in the readout said "lower it". Reading the refused record
+showed it was rule 77 "Extract intent from loose phrasing" — a false positive —
+so lowering the bar would have attached that rule to every completion report
+ever written. The statistic and the correct action pointed in opposite
+directions.
+
+What separated them was opening the record. A required `reason` is the cheapest
+mechanism that makes that step happen: a caller who must write down why has to
+have looked, and a caller who writes down something wrong has left the operator
+a sentence to disagree with. A number moved silently leaves nothing.
+
+WHAT THIS DELIBERATELY DOES NOT DO
+
+It does not decide anything itself. There is no rule here that reads a
+percentile and picks a value, and that absence is the design — the non-goal that
+survived is *statistical* auto-tuning, precisely because the statistic was the
+thing that was wrong. The judgement stays with the reader; this module only
+makes the judgement recordable and reversible.
+"""
+from __future__ import annotations
+
+import logging
+
+from sqlalchemy import select
+
+from scribe.models import async_session
+from scribe.models.retrieval_tuning import RetrievalTuningEvent
+from scribe.services.retrieval_surfaces import (
+    MAX_BUDGET,
+    budget_for,
+    floor_for,
+    get_surface,
+    surface_names,
+)
+from scribe.services.settings import set_setting
+
+logger = logging.getLogger(__name__)
+
+DIALS = ("floor", "budget")
+
+# Long enough to say what was read and what it showed; short enough that nobody
+# pastes a telemetry dump in. The number is not a measurement — it is the point
+# at which "0.66" stops being an acceptable answer to "why".
+_MIN_REASON_CHARS = 20
+
+
+def _clean_reason(reason: str) -> str:
+    """The guardrail, enforced here rather than by the column.
+
+    `reason` is NOT NULL in the schema, which "" satisfies. A required field
+    that accepts an empty string is a formality, and this one is the whole
+    mechanism — see the module docstring.
+    """
+    text = (reason or "").strip()
+    if len(text) < _MIN_REASON_CHARS:
+        raise ValueError(
+            "reason is required, and has to say what you read. A floor moved "
+            "without a stated basis is a number nobody can review or revert. "
+            "Name the evidence: which surface's telemetry, and what the refused "
+            "records actually were — `retrieval_telemetry(near_miss_samples=N)` "
+            "returns them by id, and reading them is the step that separates a "
+            "real miss from a bar doing its job."
+        )
+    return text
+
+
+async def current_settings(user_id: int) -> list[dict]:
+    """Every tunable surface with its live pair and its last stated reason.
+
+    The read side of the tuning surface, and shaped for a reader who is about to
+    change something: the value, what the arm asks and over what corpus and how
+    often — because a floor cannot be moved sensibly without those three — and
+    the reason last given, so the next change argues with the last one instead
+    of overwriting it blind.
+    """
+    out: list[dict] = []
+    async with async_session() as session:
+        for name in surface_names():
+            s = get_surface(name)
+            rows = (
+                await session.execute(
+                    select(RetrievalTuningEvent)
+                    .where(
+                        RetrievalTuningEvent.surface == name,
+                        RetrievalTuningEvent.user_id == user_id,
+                    )
+                    .order_by(RetrievalTuningEvent.created_at.desc())
+                    .limit(len(DIALS))
+                )
+            ).scalars().all()
+            last = {r.dial: r for r in rows}
+            out.append({
+                "surface": name,
+                "floor": await floor_for(user_id, name),
+                "budget": await budget_for(user_id, name),
+                "floor_default": s.floor_default,
+                "budget_default": s.budget_default,
+                "asks": s.asks,
+                "over": s.over,
+                "fires": s.fires,
+                # Absent rather than empty when a surface has never been moved:
+                # "still on the shipped starting point" is a real state and
+                # should not render as a blank reason somebody wrote.
+                "last_change": {
+                    dial: last[dial].to_dict() for dial in DIALS if dial in last
+                },
+            })
+    return out
+
+
+async def set_dial(
+    user_id: int,
+    surface: str,
+    dial: str,
+    value: float,
+    *,
+    reason: str,
+    actor: str = "model",
+) -> dict:
+    """Move one dial on one surface, recording the change and its argument.
+
+    Returns the applied value alongside the previous one, so a caller can see
+    that a clamp bit rather than assuming the number it sent is the number in
+    force — the failure being avoided is a tool reporting success for a value
+    the registry silently corrected.
+    """
+    s = get_surface(surface)                      # refuses an unknown name
+    if dial not in DIALS:
+        raise ValueError(f"dial must be one of {DIALS}, got {dial!r}")
+    if actor not in ("model", "human"):
+        raise ValueError(f"actor must be 'model' or 'human', got {actor!r}")
+    text = _clean_reason(reason)
+
+    if dial == "floor":
+        old = await floor_for(user_id, surface)
+        applied = min(1.0, max(0.0, float(value)))
+        key, stored = s.floor_key, str(applied)
+    else:
+        old = float(await budget_for(user_id, surface))
+        applied = float(min(MAX_BUDGET, max(1, int(float(value)))))
+        key, stored = s.budget_key, str(int(applied))
+
+    # A change to the value it already has is not a change, and must not be
+    # written. The Settings form re-sends every field on every save, so without
+    # this the history fills with rows saying the operator set six dials to the
+    # numbers they were already on — and a history nobody can skim is one
+    # nobody reads, which costs the surface its entire purpose.
+    #
+    # Reported rather than silently skipped, so a caller that expected to move
+    # something learns that it did not.
+    if abs(applied - old) < 1e-9:
+        return {
+            "surface": surface, "dial": dial, "previous": old,
+            "applied": applied, "clamped": abs(applied - float(value)) > 1e-9,
+            "reason": text, "actor": actor, "unchanged": True,
+        }
+
+    await set_setting(user_id, key, stored)
+    async with async_session() as session:
+        session.add(RetrievalTuningEvent(
+            user_id=user_id, surface=surface, dial=dial,
+            old_value=old, new_value=applied, actor=actor, reason=text,
+        ))
+        await session.commit()
+
+    return {
+        "surface": surface,
+        "dial": dial,
+        "previous": old,
+        "applied": applied,
+        # True when the registry corrected what was asked for. Said out loud
+        # because a caller that believes it set 1.4 will read the next
+        # telemetry as evidence about a bar that was never in force.
+        "clamped": abs(applied - float(value)) > 1e-9,
+        "reason": text,
+        "actor": actor,
+        # Always present, both ways round: a caller that has to test for the
+        # key's absence to learn the answer will eventually forget to.
+        "unchanged": False,
+    }
+
+
+async def tuning_history(
+    user_id: int, *, surface: str | None = None, limit: int = 20
+) -> list[dict]:
+    """What has been moved, newest first — the operator's review surface.
+
+    Scoped to one surface when asked, because the question is almost always
+    "why is THIS arm set like this", and an unscoped list buries one surface's
+    two changes under another's twenty.
+    """
+    if surface is not None:
+        get_surface(surface)                      # refuse a typo on the read too
+    async with async_session() as session:
+        q = (
+            select(RetrievalTuningEvent)
+            .where(RetrievalTuningEvent.user_id == user_id)
+            .order_by(RetrievalTuningEvent.created_at.desc())
+            .limit(max(1, min(int(limit), 200)))
+        )
+        if surface is not None:
+            q = q.where(RetrievalTuningEvent.surface == surface)
+        rows = (await session.execute(q)).scalars().all()
+    return [r.to_dict() for r in rows]

tests/helpers.py

@@ -322,3 +322,32 @@ def http_sink(reply: bytes = b'{"context":"","note_ids":[]}'):
     finally:
         server.shutdown()
         server.server_close()
+
+
+def writepath_cfg(**over):
+    """A complete `get_writepath_config` stand-in, built from the registry (#4102).
+
+    DERIVED, NOT LITERAL, and the reason is a failure mode this file already
+    warned about in prose without being able to prevent: the write-path hint
+    drives three arms, each of which reads its numbers out of the config dict
+    inside a fail-open `except`. A dict missing one key does not raise where a
+    reader would see it — the arm silently becomes a no-op, which is
+    indistinguishable from the arm working and finding nothing.
+
+    So the keys come from `retrieval_surfaces.SURFACES`. A seventh surface, or a
+    rename, changes this helper for free and cannot quietly disable an arm in
+    ten hand-written dicts that each looked complete on the day they were typed.
+    """
+    from scribe.services.retrieval_surfaces import SURFACES
+
+    cfg = {
+        "enabled": True,
+        "threshold": SURFACES["write_path"].floor_default,
+        "top_k": SURFACES["write_path"].budget_default,
+        "rule_threshold": SURFACES["write_path_rule"].floor_default,
+        "rule_top_k": SURFACES["write_path_rule"].budget_default,
+        "tool_rule_threshold": SURFACES["pre_tool_rule"].floor_default,
+        "tool_rule_top_k": SURFACES["pre_tool_rule"].budget_default,
+    }
+    cfg.update(over)
+    return cfg

tests/test_ledger_references_not_silence.py

@@ -0,0 +1,241 @@
+"""A repeat on a note arm is referenced, not withheld (#4101).
+
+WHY THIS EXISTS
+
+#3750 settled the argument for rules: a record the session was told about an
+hour ago is not a record in front of the reader now, so the second time it is
+the best answer the session gets the line again with a tail saying so — never
+silence, which is indistinguishable from "nothing matched".
+
+The note and snippet arms never got that fix. Worse, their ledger went into
+`semantic_search_notes` as `exclude_ids`, so the repeat left the candidate set
+entirely, which had three consequences:
+
+  - the session got silence the second time, on the arms that fire most;
+  - a compaction made it permanent, because the ledger outlived the context it
+    described (the same step fixes that one layer down);
+  - and `best_available` was measured against a candidate set the caller had
+    already edited, so the bar could be blamed for a record the caller withheld
+    (#3739, from the side its fix never reached).
+
+WHAT THIS PINS
+
+  1. The ledger does not reach the search. Asserted on the call's kwargs,
+     because this is the difference between a reference and silence and every
+     behavioural assertion below rests on it.
+  2. The repeat is rendered, and marked. The wording is NOT the rule arms' —
+     "before deciding it does not apply" is the voice of a record that binds,
+     and a dev-log borrowing it would claim authority it does not have — so
+     what is pinned is that the line appears and is distinguishable, not its
+     prose.
+  3. The telemetry splits the two (#3752 / #3668): the row's result set and the
+     surfaced table both take FRESH only, and the repeat is COUNTED in
+     `suppressed` instead. This is what makes a zero-result call readable —
+     `result_count == 0` with `suppressed_count > 0` says "everything that
+     matched, the session has already seen", which was unreportable here.
+  4. The deliberate exception: the write-path SYNC class still shows once. Its
+     claim is about an edit in progress, not about a record's continuing
+     relevance, and repeating it would be nagging rather than reminding.
+"""
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from tests.helpers import fake_note, writepath_cfg
+
+REAL_CODE = '''def debounce(fn, wait=0.25):
+    """Rate-limit a callback so it fires once after the last call."""
+    timer = None
+
+    def wrapped(*a, **kw):
+        nonlocal timer
+        if timer:
+            timer.cancel()
+        timer = threading.Timer(wait, fn, a, kw)
+        timer.start()
+
+    return wrapped
+'''
+
+
+def _wp_cfg(**over):
+    return writepath_cfg(**over)
+
+
+def _snippet_item(nid, title, user_id=1):
+    return {"id": nid, "title": title, "user_id": user_id, "note_type": "snippet"}
+
+
+# ── auto-inject ────────────────────────────────────────────────────────────
+
+async def _autoinject(hits, exclude_ids, *, rec=None, surf=None):
+    from scribe.services import plugin_context as pc
+    search = AsyncMock(return_value=hits)
+    with patch.object(pc, "get_autoinject_config", AsyncMock(
+            return_value={"enabled": True, "threshold": 0.55, "top_k": 3})), \
+         patch.object(pc, "semantic_search_notes", search), \
+         patch.object(pc, "record_retrieval", rec or MagicMock()), \
+         patch.object(pc, "record_surfaced", surf or MagicMock()), \
+         patch.object(pc, "owner_names_for", AsyncMock(return_value={})), \
+         patch.object(pc, "superseded_ids", AsyncMock(return_value=set())):
+        out = await pc.build_autoinject_hint(
+            1, "postgres pool", project_id=2, exclude_ids=exclude_ids)
+    return out, search
+
+
+@pytest.mark.asyncio
+async def test_the_ledger_never_reaches_the_search():
+    """The load-bearing one. A ledger inside the query IS the silence."""
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1))]
+    _out, search = await _autoinject(hits, [11])
+    # The menu arm runs first; the reuse slot's own call may legitimately
+    # exclude this call's menu, which is a different claim (see below).
+    menu_call = search.call_args_list[0]
+    assert not menu_call.kwargs.get("exclude_ids"), (
+        "the session ledger was passed into the search, so a repeat is "
+        "withheld rather than referenced"
+    )
+
+
+@pytest.mark.asyncio
+async def test_a_repeat_is_shown_again_and_marked():
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1)),
+            (0.78, fake_note(id=22, title="run_maintenance thresholds", user_id=1))]
+    out, _ = await _autoinject(hits, [11])
+    assert "#11" in out["context"] and "#22" in out["context"]
+    # Distinguishable, without pinning the word's neighbours in the sentence.
+    line_11 = next(ln for ln in out["context"].splitlines() if "#11" in ln)
+    line_22 = next(ln for ln in out["context"].splitlines() if "#22" in ln)
+    assert "seen" in line_11 and "seen" not in line_22
+
+
+@pytest.mark.asyncio
+async def test_the_repeat_is_counted_not_reported_as_a_result():
+    rec = MagicMock()
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1)),
+            (0.78, fake_note(id=22, title="run_maintenance thresholds", user_id=1))]
+    await _autoinject(hits, [11], rec=rec)
+    row = next(c.kwargs for c in rec.call_args_list
+               if c.kwargs["source"] == "auto_inject")
+    assert [int(n.id) for _s, n in row["results"]] == [22]
+    assert row["suppressed"] == 1
+
+
+@pytest.mark.asyncio
+async def test_a_call_where_everything_was_already_seen_is_readable():
+    """The fact that could not be expressed before.
+
+    Previously this call logged zero results with no suppression count, so it
+    was indistinguishable from a bar nothing cleared — and the operator tuning
+    that bar would have been reading the wrong number.
+    """
+    rec = MagicMock()
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1))]
+    out, _ = await _autoinject(hits, [11], rec=rec)
+    row = next(c.kwargs for c in rec.call_args_list
+               if c.kwargs["source"] == "auto_inject")
+    assert row["results"] == [] and row["suppressed"] == 1
+    # And the session still gets the line, which is the whole point.
+    assert "#11" in out["context"]
+
+
+@pytest.mark.asyncio
+async def test_a_repeat_is_not_recorded_as_a_fresh_surfacing():
+    """#3668's identity: this table and the log row describe the same call."""
+    surf = MagicMock()
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1)),
+            (0.78, fake_note(id=22, title="run_maintenance thresholds", user_id=1))]
+    await _autoinject(hits, [11], surf=surf)
+    rows = [c.kwargs for c in surf.call_args_list
+            if c.kwargs.get("source") == "auto_inject"]
+    assert rows and rows[0]["note_ids"] == [22]
+
+
+@pytest.mark.asyncio
+async def test_the_header_no_longer_promises_once_per_session():
+    """A contract stated in the prose is a contract, and this one changed.
+
+    Cheap to forget and invisible when wrong: the menu would carry a marker
+    the header had never explained, and a reader would have to guess.
+    """
+    hits = [(0.80, fake_note(id=11, title="Pool sizing decision", user_id=1))]
+    out, _ = await _autoinject(hits, [])
+    header = out["context"].splitlines()[0]
+    assert "once per session" not in header
+    assert "seen" in header
+
+
+# ── the write path ─────────────────────────────────────────────────────────
+
+async def _write_path(hits, exclude_ids, *, here=(), rec=None, sync_exclude=()):
+    from scribe.services import plugin_context as pc
+    search = AsyncMock(return_value=hits)
+    listing = AsyncMock(side_effect=[(list(here), len(here)), ([], 0)])
+    with patch.object(pc, "get_writepath_config", AsyncMock(return_value=_wp_cfg())), \
+         patch.object(pc.snippets_svc, "list_snippets", listing), \
+         patch.object(pc, "semantic_search_notes", search), \
+         patch.object(pc, "record_retrieval", rec or MagicMock()), \
+         patch.object(pc, "record_surfaced", MagicMock()), \
+         patch.object(pc, "owner_names_for", AsyncMock(return_value={})):
+        out = await pc.build_write_path_hint(
+            1, "src/x.py", code=REAL_CODE,
+            exclude_ids=list(exclude_ids),
+            exclude_sync_ids=list(sync_exclude),
+        )
+    return out, search
+
+
+@pytest.mark.asyncio
+async def test_the_write_path_ledger_does_not_reach_its_search_either():
+    hits = [(0.83, fake_note(id=11, title="debounce helper", user_id=1))]
+    _out, search = await _write_path(hits, [11])
+    assert 11 not in (search.call_args.kwargs.get("exclude_ids") or set())
+
+
+@pytest.mark.asyncio
+async def test_a_write_path_repeat_is_rendered_with_a_marker():
+    hits = [(0.83, fake_note(id=11, title="debounce helper", user_id=1))]
+    out, _ = await _write_path(hits, [11])
+    assert "#11" in out["context"]
+    assert "seen" in next(ln for ln in out["context"].splitlines() if "#11" in ln)
+
+
+@pytest.mark.asyncio
+async def test_the_write_path_counts_its_repeat():
+    rec = MagicMock()
+    hits = [(0.83, fake_note(id=11, title="debounce helper", user_id=1)),
+            (0.80, fake_note(id=22, title="throttle helper", user_id=1))]
+    await _write_path(hits, [11], rec=rec)
+    row = next(c.kwargs for c in rec.call_args_list
+               if c.kwargs["source"] == "write_path")
+    assert [int(n.id) for _s, n in row["results"]] == [22]
+    assert row["suppressed"] == 1
+
+
+@pytest.mark.asyncio
+async def test_this_calls_own_menu_is_still_excluded_from_its_search():
+    """The claim that stayed an exclusion, and must not be lost with the other.
+
+    A snippet already listed by PLACE in this same hint has nothing to gain
+    from a second line in it. That is same-call duplication, not a repeat
+    across calls, and the two were the same variable until this step.
+    """
+    hits = []
+    _out, search = await _write_path(
+        hits, [], here=[_snippet_item(7, "records this file")])
+    assert 7 in (search.call_args.kwargs.get("exclude_ids") or set())
+
+
+@pytest.mark.asyncio
+async def test_the_sync_class_still_shows_only_once():
+    """The deliberate exception, pinned so it reads as a decision.
+
+    The sync nudge says "you are editing the file this record describes, so
+    updating it is part of the edit". Repeated every write to the same file it
+    is nagging, and unlike a reuse suggestion it is not a claim whose relevance
+    can return — it either got acted on or it did not.
+    """
+    out, _ = await _write_path(
+        [], [], here=[_snippet_item(7, "records this file")], sync_exclude=[7])
+    assert out["sync_note_ids"] == []
+    assert "#7" not in out["context"]

tests/test_note_usage.py

@@ -20,7 +20,7 @@ from scribe.services.note_usage import (
     record_surfaced,
     usage_for_notes,
 )
-from tests.helpers import fake_note
+from tests.helpers import fake_note, writepath_cfg
 
 
 # --- recording ------------------------------------------------------------
@@ -154,8 +154,7 @@ async def test_unscored_location_arms_are_recorded(lookups, expected_source):
         patch.object(
             plugin_context,
             "get_writepath_config",
-            AsyncMock(return_value={"enabled": True, "threshold": 0.55, "top_k": 3,
-                                    "rule_threshold": 0.72}),
+            AsyncMock(return_value=writepath_cfg(threshold=0.55)),
         ),
         patch.object(
             plugin_context.snippets_svc,

tests/test_retrieval_surfaces.py

@@ -0,0 +1,187 @@
+"""The surface registry, and the identity the whole tuning story rests on (#4102).
+
+WHY THIS EXISTS
+
+Six arms used to own their own numbers: a settings key, a default, and a limit
+that was usually a module constant nobody could change. That survived while the
+values were shipped constants. It stops surviving once the operator's decision
+is that the numbers MOVE:
+
+    "the floor should be chosen and adjusted by the model using it… the user
+    should be able to touch it but the model should be the thing handling it 9
+    times out of 10."
+
+A tuning surface cannot be model-consistent across arms that each spell their
+configuration differently, so the arms now read `{floor, budget}` from one
+registry.
+
+WHAT THIS PINS
+
+  1. **A surface's name IS its telemetry source.** This is the load-bearing
+     one. The tool that moves a floor and the table that reports what the floor
+     did have to be naming the same arm, and nothing in the type system says so
+     — `record_retrieval(source="pre_tool_rule")` is a string literal in a
+     different file. Renaming one without the other produces a surface that can
+     be tuned and cannot be measured, or measured and not tuned, and both fail
+     silently.
+  2. **Keys are unique.** Two surfaces sharing a settings key is how
+     `report_preference` spent its first release moving whenever the prompt arm
+     was tuned (#3860) — one dial wearing two labels.
+  3. **An unknown surface is refused.** Settings keys are free-form strings in
+     a generic table, so a typo'd name would write a key nothing reads: a
+     change that appears to succeed, reports a new value, and alters nothing.
+  4. **The budget clamps at 1, never 0.** A zero-budget arm searches, logs a
+     retrieval and renders nothing — indistinguishable in the telemetry from a
+     bar nothing cleared, which is the exact confusion this milestone exists to
+     remove. "Off" is what the `enabled` switch is for.
+  5. **`write_path` inherits auto-inject's budget when it has none.** It used
+     to share that key outright; giving it its own without a fallback would
+     silently reset the budget on every install that had tuned the shared one.
+"""
+from unittest.mock import AsyncMock, patch
+
+import pytest
+
+from scribe.services import retrieval_surfaces as rs
+
+SERVICES = ("plugin_context", "reply_preferences")
+
+
+def _service_source(name: str) -> str:
+    from pathlib import Path
+    root = Path(__file__).resolve().parents[1] / "src" / "scribe" / "services"
+    return (root / f"{name}.py").read_text()
+
+
+def test_every_surface_name_is_a_real_telemetry_source():
+    """The join key, checked against the arms that emit it.
+
+    Asserted on the source text rather than by calling the arms, because what
+    can rot here is the literal: a surface renamed in the registry and not in
+    the `record_retrieval(source=…)` call still runs, still logs, and still
+    tunes — just against two different names, so the readout an operator uses
+    to justify a change describes a different arm from the one the change hits.
+    """
+    blob = "\n".join(_service_source(n) for n in SERVICES)
+    # `report_preference` passes its name through a module constant rather than
+    # a literal, so that one name is satisfied by the constant holding it.
+    from scribe.services.reply_preferences import SOURCE
+
+    missing = [
+        s.name for s in rs.SURFACES.values()
+        if f'source="{s.name}"' not in blob and s.name != SOURCE
+    ]
+    assert not missing, (
+        f"these surfaces can be tuned but never measured: {missing}. The "
+        "registry name must match the string the arm passes to record_retrieval."
+    )
+
+
+def test_no_two_surfaces_share_a_settings_key():
+    """One dial, one label. #3860 is what the other way costs."""
+    floors = [s.floor_key for s in rs.SURFACES.values()]
+    budgets = [s.budget_key for s in rs.SURFACES.values()]
+    assert len(set(floors)) == len(floors), f"duplicate floor key in {floors}"
+    assert len(set(budgets)) == len(budgets), f"duplicate budget key in {budgets}"
+    assert not (set(floors) & set(budgets)), "a floor key doubles as a budget key"
+
+
+def test_every_surface_says_what_it_asks_over_what_and_how_often():
+    """The prose is rendered, not decorative.
+
+    A floor cannot be moved responsibly by anyone — model or human — who does
+    not know the query shape, the corpus, or how often the arm costs something.
+    An empty string here reaches the tuning tool and the Settings UI as a blank.
+    """
+    for s in rs.SURFACES.values():
+        for field in ("asks", "over", "fires"):
+            assert getattr(s, field).strip(), f"{s.name}.{field} is empty"
+
+
+def test_an_unknown_surface_is_refused_rather_than_written():
+    with pytest.raises(ValueError) as e:
+        rs.get_surface("pretool_rule")          # a real typo for pre_tool_rule
+    # The message has to name the alternatives, or the caller's next move is a
+    # second guess.
+    assert "pre_tool_rule" in str(e.value)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("stored, expected", [
+    ("0.8", 0.8),
+    ("5", 1.0),            # clamped, not believed
+    ("-3", 0.0),
+    ("banana", 0.55),      # unparseable falls back to the surface's default
+    ("", 0.55),
+])
+async def test_a_floor_is_clamped_to_the_unit_interval(stored, expected):
+    with patch.object(rs, "get_setting", AsyncMock(return_value=stored)):
+        assert await rs.floor_for(1, "auto_inject") == expected
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("stored, expected", [
+    ("4", 4),
+    ("999", rs.MAX_BUDGET),
+    ("0", 1),
+    ("-2", 1),
+    ("banana", 3),
+])
+async def test_a_budget_is_clamped_with_a_floor_of_one(stored, expected):
+    """Zero is the value that must not get through.
+
+    An arm with a budget of 0 runs its search, writes a `retrieval_logs` row
+    with `result_count == 0`, and renders nothing — which reads in the telemetry
+    exactly like a bar nothing cleared. Turning a surface off is the `enabled`
+    switch's job, and that one says so.
+    """
+    with patch.object(rs, "get_setting", AsyncMock(return_value=stored)):
+        assert await rs.budget_for(1, "auto_inject") == expected
+
+
+@pytest.mark.asyncio
+async def test_the_write_path_budget_falls_back_to_auto_injects():
+    """The migration this fallback exists for.
+
+    `write_path` had no budget key of its own — it read auto-inject's. An
+    install that had tuned that shared knob to 6 must not silently drop to the
+    new key's default the day this ships; nothing would look broken and the
+    operator would never know to look.
+    """
+    async def _setting(_uid, key, default=""):
+        return {"kb_writepath_top_k": "", "kb_autoinject_top_k": "6"}.get(key, default)
+
+    with patch.object(rs, "get_setting", AsyncMock(side_effect=_setting)):
+        assert await rs.budget_for(1, "write_path") == 6
+
+
+@pytest.mark.asyncio
+async def test_its_own_budget_wins_once_it_is_set():
+    """And the fallback must not become a permanent override."""
+    async def _setting(_uid, key, default=""):
+        return {"kb_writepath_top_k": "2", "kb_autoinject_top_k": "6"}.get(key, default)
+
+    with patch.object(rs, "get_setting", AsyncMock(side_effect=_setting)):
+        assert await rs.budget_for(1, "write_path") == 2
+
+
+@pytest.mark.asyncio
+async def test_the_write_path_config_carries_every_arm_it_drives():
+    """One hook request drives three arms, and each reads its pair out of this.
+
+    A missing key does not raise where a reader would see it — the rule arms
+    fail open, so a KeyError becomes an empty hint, and the arm reads as "fired
+    and found nothing". That is the failure this asserts against, and it is the
+    reason tests build the dict from the registry rather than by hand.
+    """
+    from scribe.services import plugin_context as pc
+
+    # Both modules read settings: `pc` for the enabled switch, `rs` for the
+    # pairs. Patching one and not the other reaches a real database.
+    with patch.object(pc, "get_setting", AsyncMock(return_value="")), \
+         patch.object(rs, "get_setting", AsyncMock(return_value="")):
+        cfg = await pc.get_writepath_config(1)
+
+    for key in ("threshold", "top_k", "rule_threshold", "rule_top_k",
+                "tool_rule_threshold", "tool_rule_top_k"):
+        assert key in cfg, f"{key} missing — its arm will silently no-op"

tests/test_retrieval_tuning.py

@@ -0,0 +1,199 @@
+"""Moving a floor, and the reason that has to come with it (#4102).
+
+WHY THIS EXISTS
+
+The operator handed the dial to the model: *"the user should be able to touch it
+but the model should be the thing handling it 9 times out of 10."* Everything
+here guards the half of that sentence people skip — the operator still has to be
+able to see what was done on their behalf and disagree with it.
+
+WHAT THIS PINS
+
+  1. **A reason is required, and "" does not count.** The column is NOT NULL,
+     which an empty string satisfies; the service is where the requirement is
+     real. This is the whole guardrail: a caller who must write down why has to
+     have looked, and a caller who writes down something wrong leaves the
+     operator a sentence to argue with. A number that moved silently leaves
+     nothing.
+  2. **The change is recorded, with what it was before.** Without `old_value` a
+     history cannot answer "was this always like that", which is the first
+     question anyone asks of a surface behaving oddly.
+  3. **A clamp is reported, never swallowed.** A caller that believes it set 1.4
+     will read the next telemetry as evidence about a bar that was never in
+     force — the same class of error as #3739, one layer up.
+  4. **An unknown surface is refused before anything is written.** Settings keys
+     are free-form strings, so a typo'd surface would write a key nothing reads:
+     a change that reports success and alters nothing.
+  5. **The tool teaches the procedure that works**, not the one the numbers
+     suggest. Asserted on the docstring because the docstring IS the contract an
+     agent reads, and the failure it prevents is a model tuning from a
+     percentile — which has been measured pointing the wrong way.
+"""
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from scribe.services import retrieval_tuning as rt
+from tests.helpers import make_mock_session
+
+
+def _patches(floor=0.72, budget=3):
+    """Patch everything `set_dial` touches except the thing under test."""
+    session = make_mock_session()
+    return session, (
+        patch.object(rt, "async_session", MagicMock(return_value=session)),
+        patch.object(rt, "set_setting", AsyncMock()),
+        patch.object(rt, "floor_for", AsyncMock(return_value=floor)),
+        patch.object(rt, "budget_for", AsyncMock(return_value=budget)),
+    )
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("reason", ["", "   ", "noisy", "too high"])
+async def test_a_change_without_a_real_reason_is_refused(reason):
+    """The guardrail. "too high" is a restatement of the change, not a basis."""
+    session, ctx = _patches()
+    with ctx[0], ctx[1], ctx[2], ctx[3], pytest.raises(ValueError) as e:
+        await rt.set_dial(1, "prompt_rule", "floor", 0.66, reason=reason)
+    # The message has to name the tool that produces a real basis, or the
+    # caller's next move is a longer sentence rather than a look at the records.
+    assert "near_miss_samples" in str(e.value)
+    session.add.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_nothing_is_written_when_the_reason_is_refused():
+    """Refused BEFORE the setting is touched, not after.
+
+    Writing the value and then raising would leave the number moved and the
+    history empty — the exact state this table exists to make impossible.
+    """
+    session, ctx = _patches()
+    with ctx[0], patch.object(rt, "set_setting", AsyncMock()) as setter, \
+         ctx[2], ctx[3]:
+        with pytest.raises(ValueError):
+            await rt.set_dial(1, "prompt_rule", "floor", 0.66, reason="x")
+        setter.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_a_good_change_writes_the_setting_and_the_event():
+    session, ctx = _patches(floor=0.72)
+    reason = ("read prompt_rule's 5 highest declines: 3 were project rules for "
+              "another repo, so the bar is doing its job here")
+    with ctx[0], patch.object(rt, "set_setting", AsyncMock()) as setter, \
+         ctx[2], ctx[3]:
+        out = await rt.set_dial(1, "prompt_rule", "floor", 0.66, reason=reason)
+
+    setter.assert_awaited_once()
+    _uid, key, stored = setter.await_args.args
+    assert key == "kb_promptrule_threshold" and stored == "0.66"
+
+    event = session.add.call_args.args[0]
+    assert event.surface == "prompt_rule" and event.dial == "floor"
+    # The before-value is what makes the history answerable.
+    assert event.old_value == 0.72 and event.new_value == 0.66
+    assert event.reason == reason and event.actor == "model"
+    assert out["previous"] == 0.72 and out["applied"] == 0.66
+    assert out["clamped"] is False
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("dial, sent, applied", [
+    ("floor", 1.4, 1.0),
+    ("floor", -0.2, 0.0),
+    ("budget", 99, 10),
+    ("budget", 0, 1),
+])
+async def test_a_clamp_is_reported_rather_than_swallowed(dial, sent, applied):
+    """Said out loud, because silence here poisons the next reading.
+
+    A caller that believes it set 1.4 treats the following week's telemetry as
+    evidence about a bar that never existed, and then moves the dial again to
+    fix a problem it invented.
+    """
+    session, ctx = _patches()
+    reason = "checked the refused records for this surface and they were fine"
+    with ctx[0], ctx[1], ctx[2], ctx[3]:
+        out = await rt.set_dial(1, "auto_inject", dial, sent, reason=reason)
+    assert out["applied"] == applied
+    assert out["clamped"] is True
+
+
+@pytest.mark.asyncio
+async def test_an_unknown_surface_is_refused_before_anything_is_written():
+    session, ctx = _patches()
+    with ctx[0], patch.object(rt, "set_setting", AsyncMock()) as setter, \
+         ctx[2], ctx[3]:
+        with pytest.raises(ValueError):
+            await rt.set_dial(1, "pretool_rule", "floor", 0.6,
+                              reason="a perfectly good reason that is long enough")
+        setter.assert_not_called()
+    session.add.assert_not_called()
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("dial", ["threshold", "limit", "", "FLOOR"])
+async def test_an_unknown_dial_is_refused(dial):
+    """The near-misses are the old vocabulary — `threshold` and `limit` are what
+    these were called before this step, so they are exactly what a stale caller
+    will send, and a silent no-op there would be indistinguishable from a
+    change that did not take."""
+    session, ctx = _patches()
+    with ctx[0], ctx[1], ctx[2], ctx[3], pytest.raises(ValueError):
+        await rt.set_dial(1, "auto_inject", dial, 0.6,
+                          reason="a perfectly good reason that is long enough")
+    session.add.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_a_human_change_is_distinguishable_from_the_models():
+    """Both act as the same user, so the id cannot tell them apart — and "did I
+    do this, or did the session?" is the first question the history is asked."""
+    session, ctx = _patches()
+    with ctx[0], ctx[1], ctx[2], ctx[3]:
+        await rt.set_dial(1, "auto_inject", "floor", 0.6, actor="human",
+                          reason="operator set this themselves in Settings")
+    assert session.add.call_args.args[0].actor == "human"
+
+
+@pytest.mark.asyncio
+async def test_an_unknown_actor_is_refused():
+    """Free text here would make the column unreadable within a month."""
+    session, ctx = _patches()
+    with ctx[0], ctx[1], ctx[2], ctx[3], pytest.raises(ValueError):
+        await rt.set_dial(1, "auto_inject", "floor", 0.6, actor="agent",
+                          reason="a perfectly good reason that is long enough")
+
+
+def test_the_tool_teaches_reading_the_records_not_the_percentile():
+    """The contract an agent actually reads (rule 167).
+
+    The failure this prevents is a model moving a bar because `near_misses.p90`
+    sat close to it. That has been measured pointing the wrong way — 69 declines
+    where every percentile said "lower it" and the refused record was a false
+    positive — so the docstring has to carry the method, not just the warning.
+    """
+    from scribe.mcp.tools import retrieval_tuning as tool
+
+    doc = tool.tune_retrieval.__doc__
+    assert "near_miss_samples" in doc, "the tool does not name how to get records"
+    assert "PERCENTILE ALONE" in doc.upper()
+    # And the worked example, because an abstract warning loses to a number.
+    assert "69" in doc
+
+
+def test_all_three_tools_are_registered():
+    from scribe.mcp.tools import retrieval_tuning as tool
+
+    names = []
+
+    class _MCP:
+        def tool(self, name):
+            names.append(name)
+            return lambda fn: fn
+
+    tool.register(_MCP())
+    assert names == [
+        "retrieval_surfaces", "tune_retrieval", "retrieval_tuning_history",
+    ]

tests/test_routes_retrieval_tuning.py

@@ -0,0 +1,133 @@
+"""The operator's half of the tuning surface (#4102).
+
+WHY THIS EXISTS
+
+The model moves these dials — that is the operator's decision for milestone
+416 — so the browser's job is no longer "set the number". It is to show what
+was set, by whom, and on what argument, and to let the operator disagree.
+
+The load-bearing guard here is the last one. `/api/settings` is a generic
+key-value endpoint that accepts any key at all, and every retrieval floor IS an
+ordinary settings key. A floor written straight through it would land correctly
+and record nothing — a tuning history with holes in it, which is worse than no
+history because it reads as complete. So the generic endpoint routes those keys
+through `set_dial`, and that routing is asserted rather than remembered.
+"""
+import inspect
+
+import pytest
+
+
+def test_retrieval_blueprint_registered():
+    from scribe.routes.retrieval import retrieval_bp
+    assert retrieval_bp.name == "retrieval"
+    assert retrieval_bp.url_prefix == "/api/retrieval"
+
+
+def test_retrieval_blueprint_registered_in_app():
+    from scribe.app import create_app
+    app = create_app()
+    assert "retrieval" in app.blueprints
+
+
+def test_every_endpoint_is_reachable_on_the_app():
+    """Handlers existing is not the same as them being routed."""
+    from scribe.app import create_app
+    app = create_app()
+    rules = {
+        str(r.rule) for r in app.url_map.iter_rules()
+        if r.endpoint.startswith("retrieval.")
+    }
+    assert rules == {
+        "/api/retrieval/surfaces",
+        "/api/retrieval/surfaces/<surface>",
+        "/api/retrieval/tuning-history",
+    }
+
+
+def test_the_browser_and_the_agent_call_the_same_service():
+    """Rule 33 parity. Two callers, one service — or the two surfaces drift and
+    the guard that a reason is required exists on only one of them."""
+    from scribe.mcp.tools import retrieval_tuning as tool
+    from scribe.routes import retrieval as routes
+    from scribe.services import retrieval_tuning as svc
+
+    assert routes.set_dial is svc.set_dial
+    assert tool.tuning_svc is svc
+
+
+def test_the_route_does_not_take_the_actor_from_the_caller():
+    """`actor` is the one field a reviewer leans on to answer "did I do this,
+    or did the session?". A payload-supplied actor would let a model claim to
+    be the operator, which turns the column into decoration."""
+    from scribe.routes import retrieval as routes
+
+    src = inspect.getsource(routes.tune_surface_route)
+    assert 'actor="human"' in src
+    assert 'data.get("actor"' not in src and 'data["actor"]' not in src
+
+
+# ── the hole the generic settings endpoint would otherwise leave ────────────
+
+def test_every_registry_key_is_recognised_as_a_dial():
+    """Derived from the registry, both directions. A seventh surface added
+    without a row here is a floor that can be written silently again."""
+    from scribe.services.retrieval_surfaces import SURFACES, dial_for_key
+
+    for name, surface in SURFACES.items():
+        assert dial_for_key(surface.floor_key) == (name, "floor")
+        assert dial_for_key(surface.budget_key) == (name, "budget")
+
+
+def test_an_ordinary_setting_is_not_mistaken_for_a_dial():
+    """The interception must be narrow. A false positive here would send an
+    unrelated setting through a service that parses it as a float and rejects
+    the save."""
+    from scribe.services.retrieval_surfaces import dial_for_key
+
+    for key in ("smtp_password", "kb_autoinject_enabled", "theme",
+                "kb_planmatch_threshold", ""):
+        assert dial_for_key(key) is None, key
+
+
+def test_the_settings_endpoint_routes_a_dial_through_the_recorder():
+    """THE GUARD. Asserted on the source because the alternative is a full
+    request-context round trip for a branch whose whole content is "which
+    function gets called" — and because what must not regress is precisely
+    that this module reaches for `set_dial` at all."""
+    from scribe.routes import settings as routes
+
+    src = inspect.getsource(routes.update_settings_route)
+    assert "dial_for_key" in src, (
+        "the generic settings endpoint no longer recognises retrieval dials — "
+        "a floor written through it now moves with no event recorded, and the "
+        "tuning history will say nothing happened"
+    )
+    assert "set_dial" in src
+    assert 'actor="human"' in src
+
+
+@pytest.mark.asyncio
+async def test_setting_a_dial_to_the_value_it_already_has_records_nothing():
+    """The Settings form re-sends every field on every save. Without this, one
+    press of Save writes six rows saying the operator set six dials to the
+    numbers they were already on — and a history nobody can skim is one nobody
+    reads."""
+    from unittest.mock import AsyncMock, MagicMock, patch
+
+    from scribe.services import retrieval_tuning as rt
+    from tests.helpers import make_mock_session
+
+    session = make_mock_session()
+    with patch.object(rt, "async_session", MagicMock(return_value=session)), \
+         patch.object(rt, "set_setting", AsyncMock()) as setter, \
+         patch.object(rt, "floor_for", AsyncMock(return_value=0.72)), \
+         patch.object(rt, "budget_for", AsyncMock(return_value=3)):
+        out = await rt.set_dial(1, "prompt_rule", "floor", 0.72,
+                                reason="re-saved the settings form untouched")
+
+    assert out["unchanged"] is True
+    session.add.assert_not_called()
+    # And the setting is left alone too: rewriting the same value would bump
+    # whatever timestamp the row carries for no reason.
+    setter.assert_not_called()

tests/test_rule_opened_ledger.py

@@ -135,21 +135,9 @@ def test_an_event_with_nothing_usable_records_nothing_and_still_exits_zero(event
     assert not led.exists()
 
 
-# ── the two ledgers stay in step ───────────────────────────────────────────
-
-def test_a_compaction_clears_both_ledgers():
-    """The one that would be worst to get wrong. `.opened.ids` describes a
-    context the compaction just destroyed, so keeping it while clearing the
-    naming ledger would have the arms telling a freshly-summarised session
-    "you opened it earlier" about a rule now nowhere in its context.
-    """
-    sh = (HOOKS / "scribe_session_context.sh").read_text()
-    block = sh.split("case \"$source\" in")[1].split("esac")[0]
-    assert "compact|clear)" in block
-    for led in (".rules.ids", ".opened.ids"):
-        assert re.search(rf"rm -f .*{re.escape(led)}", block), (
-            f"{led} survives a compaction that destroyed what it describes"
-        )
+# What a compaction clears — including `.opened.ids`, whose claim is the one
+# that would be worst to get wrong — is asserted against the running hook in
+# tests/test_session_ledger_clear.py, so there is one home for it.
 
 
 def test_the_recorder_is_registered_on_the_get_rule_tool():

tests/test_rule_usage_wiring.py

@@ -17,7 +17,8 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-from tests.helpers import fake_note, fake_rule
+from scribe.services import retrieval_surfaces as rs
+from tests.helpers import fake_note, fake_rule, writepath_cfg
 
 # The MCP tool layer reads its caller from a ContextVar the HTTP transport sets
 # per request; a unit test has no request, so it binds the caller itself. The
@@ -59,16 +60,15 @@ def _arm_patches(pc, hits, recorder, prior_art=None, cfg=None, rule_search=None,
     """
     return (
         patch.object(pc, "get_writepath_config",
-                     AsyncMock(return_value=cfg or {
-                         "enabled": True, "threshold": 0.6,
-                         "top_k": 3, "rule_threshold": 0.6,
-                         # The command arm reads its OWN bar since #3853, and
-                         # a stub missing this key does not fail where a
-                         # reader would see it: the arm fails open, so the
-                         # KeyError becomes an empty hint and every case in
-                         # _ARMS reports the arm went silent instead.
-                         "tool_rule_threshold": 0.6,
-                     })),
+                     # Every key, derived from the surface registry (#4102).
+                     # A stub missing one does not fail where a reader would
+                     # see it: the arm fails open, so the KeyError becomes an
+                     # empty hint and every case in _ARMS reports the arm went
+                     # silent instead.
+                     AsyncMock(return_value=cfg or writepath_cfg(
+                         threshold=0.6, rule_threshold=0.6,
+                         tool_rule_threshold=0.6,
+                     ))),
         patch.object(pc.snippets_svc, "list_snippets", AsyncMock(return_value=([], 0))),
         patch.object(pc, "semantic_search_notes",
                      AsyncMock(return_value=_PRIOR_ART if prior_art is None
@@ -156,8 +156,7 @@ async def test_the_arm_searches_on_its_OWN_bar_not_the_code_one():
     with ExitStack() as stack:
         for ctx in _arm_patches(
             pc, [], MagicMock(), rule_search=search,
-            cfg={"enabled": True, "threshold": 0.60,
-                 "top_k": 3, "rule_threshold": 0.81},
+            cfg=writepath_cfg(threshold=0.60, top_k=3, rule_threshold=0.81),
         ):
             stack.enter_context(ctx)
         await pc.build_write_path_hint(
@@ -392,16 +391,15 @@ def test_every_rules_payload_caller_names_itself():
 def _tool_patches(pc, hits, recorder, cfg=None, retrieval_log=None):
     return (
         patch.object(pc, "get_writepath_config",
-                     AsyncMock(return_value=cfg or {
-                         "enabled": True, "threshold": 0.6,
-                         "top_k": 3, "rule_threshold": 0.6,
-                         # The command arm reads its OWN bar since #3853, and
-                         # a stub missing this key does not fail where a
-                         # reader would see it: the arm fails open, so the
-                         # KeyError becomes an empty hint and every case in
-                         # _ARMS reports the arm went silent instead.
-                         "tool_rule_threshold": 0.6,
-                     })),
+                     # Every key, derived from the surface registry (#4102).
+                     # A stub missing one does not fail where a reader would
+                     # see it: the arm fails open, so the KeyError becomes an
+                     # empty hint and every case in _ARMS reports the arm went
+                     # silent instead.
+                     AsyncMock(return_value=cfg or writepath_cfg(
+                         threshold=0.6, rule_threshold=0.6,
+                         tool_rule_threshold=0.6,
+                     ))),
         patch.object(pc, "semantic_search_rules", AsyncMock(return_value=hits)),
         patch.object(pc, "record_retrieval", retrieval_log or MagicMock()),
         patch.object(pc, "record_rule_surfaced", recorder),
@@ -433,9 +431,10 @@ async def _run_tool_arm(hits, recorder, command="curl -s https://git.example/api
 
 def _prompt_patches(pc, hits, recorder, retrieval_log=None):
     return (
-        # The arm reads its own threshold key rather than a shared config
-        # object — a third corpus with a bar nothing has yet tuned for it.
-        patch.object(pc, "get_setting", AsyncMock(return_value="0.6")),
+        # The arm reads its own floor and budget from the surface registry
+        # rather than a shared config object (#4102) — a third corpus, with a
+        # pair nothing has yet tuned for it.
+        patch.object(rs, "get_setting", AsyncMock(return_value="0.6")),
         patch.object(pc, "semantic_search_rules", AsyncMock(return_value=hits)),
         patch.object(pc, "record_retrieval", retrieval_log or MagicMock()),
         patch.object(pc, "record_rule_surfaced", recorder),
@@ -469,7 +468,7 @@ async def test_the_prompt_arm_retrieves_against_what_the_operator_SAID():
     ))])
     from scribe.services import plugin_context as pc
     with ExitStack() as stack:
-        stack.enter_context(patch.object(pc, "get_setting", AsyncMock(return_value="0.6")))
+        stack.enter_context(patch.object(rs, "get_setting", AsyncMock(return_value="0.6")))
         stack.enter_context(patch.object(pc, "semantic_search_rules", search))
         stack.enter_context(patch.object(pc, "record_retrieval", MagicMock()))
         stack.enter_context(patch.object(pc, "record_rule_surfaced", rec))
@@ -503,7 +502,7 @@ async def test_the_prompt_arm_says_nothing_when_asked_nothing():
     log = MagicMock()
     from scribe.services import plugin_context as pc
     with ExitStack() as stack:
-        stack.enter_context(patch.object(pc, "get_setting", AsyncMock(return_value="0.6")))
+        stack.enter_context(patch.object(rs, "get_setting", AsyncMock(return_value="0.6")))
         stack.enter_context(patch.object(pc, "semantic_search_rules", search))
         stack.enter_context(patch.object(pc, "record_retrieval", log))
         stack.enter_context(patch.object(pc, "record_rule_surfaced", MagicMock()))
@@ -1416,7 +1415,7 @@ async def _run_slot(general, preference, recorder=None, retrieval_log=None, **kw
     from scribe.services import plugin_context as pc
     rec = recorder or MagicMock()
     with ExitStack() as stack:
-        stack.enter_context(patch.object(pc, "get_setting", AsyncMock(return_value="0.6")))
+        stack.enter_context(patch.object(rs, "get_setting", AsyncMock(return_value="0.6")))
         stack.enter_context(patch.object(
             pc, "semantic_search_rules", _search_by_kind(general, preference)))
         stack.enter_context(patch.object(
@@ -1480,7 +1479,7 @@ async def test_the_slot_query_can_only_answer_with_a_preference():
     from scribe.services import plugin_context as pc
     search = _search_by_kind(_RULES_FILLING_THE_LIMIT, _PREF_HIT)
     with ExitStack() as stack:
-        stack.enter_context(patch.object(pc, "get_setting", AsyncMock(return_value="0.6")))
+        stack.enter_context(patch.object(rs, "get_setting", AsyncMock(return_value="0.6")))
         stack.enter_context(patch.object(pc, "semantic_search_rules", search))
         stack.enter_context(patch.object(pc, "record_retrieval", MagicMock()))
         stack.enter_context(patch.object(pc, "record_rule_surfaced", MagicMock()))
@@ -1617,8 +1616,7 @@ async def test_each_act_arm_searches_at_its_own_bar():
     """The split, where it actually takes effect."""
     from scribe.services import plugin_context as pc
 
-    cfg = {"enabled": True, "threshold": 0.6, "top_k": 3,
-           "rule_threshold": 0.77, "tool_rule_threshold": 0.61}
+    cfg = writepath_cfg(threshold=0.6, top_k=3, rule_threshold=0.77, tool_rule_threshold=0.61)
 
     search = AsyncMock(return_value=list(_THREE_HITS))
     with ExitStack() as stack:
@@ -1646,8 +1644,7 @@ async def test_an_act_arm_reports_the_bar_it_actually_searched_at():
     """
     from scribe.services import plugin_context as pc
 
-    cfg = {"enabled": True, "threshold": 0.6, "top_k": 3,
-           "rule_threshold": 0.77, "tool_rule_threshold": 0.61}
+    cfg = writepath_cfg(threshold=0.6, top_k=3, rule_threshold=0.77, tool_rule_threshold=0.61)
 
     search = AsyncMock(return_value=list(_THREE_HITS))
     log = MagicMock()
@@ -1712,8 +1709,7 @@ async def test_the_act_arms_scope_their_search_to_the_bound_project(bound, scope
     global rules only, which the search spells as `project_id=None`."""
     from scribe.services import plugin_context as pc
 
-    cfg = {"enabled": True, "threshold": 0.6, "top_k": 3,
-           "rule_threshold": 0.6, "tool_rule_threshold": 0.6}
+    cfg = writepath_cfg(threshold=0.6, top_k=3, rule_threshold=0.6, tool_rule_threshold=0.6)
     tool_search = AsyncMock(return_value=[])
     with ExitStack() as stack:
         stack.enter_context(patch.object(
@@ -1726,7 +1722,7 @@ async def test_the_act_arms_scope_their_search_to_the_bound_project(bound, scope
 
     prompt_search = AsyncMock(return_value=[])
     with ExitStack() as stack:
-        stack.enter_context(patch.object(pc, "get_setting", AsyncMock(return_value="0.6")))
+        stack.enter_context(patch.object(rs, "get_setting", AsyncMock(return_value="0.6")))
         stack.enter_context(patch.object(pc, "semantic_search_rules", prompt_search))
         stack.enter_context(patch.object(pc, "record_retrieval", MagicMock()))
         stack.enter_context(patch.object(pc, "record_rule_surfaced", MagicMock()))

tests/test_services_backup.py

@@ -23,7 +23,7 @@ def test_backup_version_is_current():
 
     (Named for the number it asserted until v10, which is exactly the drift a
     name-carrying-a-value invites; it now says what it checks.)"""
-    assert backup.BACKUP_VERSION == 15
+    assert backup.BACKUP_VERSION == 16
 
 
 def _exportable_note(**over):
@@ -134,6 +134,7 @@ def _column_guard_targets():
     from scribe.models.note_supersession import NoteSupersession
     from scribe.models.note_usage import NoteUsageEvent
     from scribe.models.rule_usage import RuleUsageEvent
+    from scribe.models.retrieval_tuning import RetrievalTuningEvent
     from scribe.models.note_version import NoteVersion
     from scribe.models.rule_version import RuleVersion
     from scribe.models.project import Project
@@ -164,6 +165,9 @@ def _column_guard_targets():
         "rule_relations": (RuleRelation, backup._rule_relation_rows),
         "note_usage_events": (NoteUsageEvent, backup._usage_event_rows),
         "rule_usage_events": (RuleUsageEvent, backup._rule_usage_event_rows),
+        "retrieval_tuning_events": (
+            RetrievalTuningEvent, backup._retrieval_tuning_event_rows,
+        ),
         "design_systems": (DesignSystem, backup._design_system_rows),
         "design_tokens": (DesignToken, backup._design_token_rows),
         "repo_bindings": (RepoBinding, backup._repo_binding_rows),
@@ -340,7 +344,9 @@ async def test_export_full_backup_contains_every_declared_section():
                 "systems", "record_systems", "design_systems",
                 "design_tokens", "note_usage_events", "repo_bindings",
                 "note_supersessions", "code_shapes", "code_shape_events",
-                "code_shape_uses"):
+                "code_shape_uses",
+                # v16: the reasons beside the settings they explain.
+                "retrieval_tuning_events"):
         assert key in out, f"missing export section: {key}"
         assert out[key] == []
 

tests/test_services_plugin_context.py

@@ -1,7 +1,8 @@
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
-from tests.helpers import fake_note
+from scribe.services import retrieval_surfaces as rs
+from tests.helpers import fake_note, writepath_cfg
 
 
 pytestmark = pytest.mark.usefixtures("_no_supersession")
@@ -17,7 +18,8 @@ async def test_get_autoinject_config_defaults_and_clamps():
     from scribe.services import plugin_context as pc
 
     # No settings stored → defaults.
-    with patch.object(pc, "get_setting", AsyncMock(side_effect=lambda uid, k, d: d)):
+    with patch.object(pc, "get_setting", AsyncMock(side_effect=lambda uid, k, d: d)), \
+         patch.object(rs, "get_setting", AsyncMock(side_effect=lambda uid, k, d="": d)):
         cfg = await pc.get_autoinject_config(1)
     assert cfg == {
         "enabled": pc.AUTOINJECT_DEFAULT_ENABLED,
@@ -31,8 +33,12 @@ async def test_get_autoinject_config_defaults_and_clamps():
         pc.AUTOINJECT_THRESHOLD_KEY: "5",
         pc.AUTOINJECT_TOP_K_KEY: "999",
     }
-    with patch.object(pc, "get_setting",
-                      AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+    # The switch comes from plugin_context, the two numbers from the registry.
+    def _side(uid, k, d=""):
+        return stored.get(k, d)
+
+    with patch.object(pc, "get_setting", AsyncMock(side_effect=_side)), \
+         patch.object(rs, "get_setting", AsyncMock(side_effect=_side)):
         cfg = await pc.get_autoinject_config(1)
     assert cfg["enabled"] is False
     assert cfg["threshold"] == 1.0
@@ -437,9 +443,7 @@ async def test_write_path_semantic_arm_asks_for_experience_not_just_snippets():
     search = AsyncMock(return_value=hits)
     rec = MagicMock()
     with patch.object(pc, "get_writepath_config",
-                      AsyncMock(return_value={"enabled": True, "threshold": 0.6,
-                                              "top_k": 3,
-                                              "rule_threshold": 0.72})), \
+                      AsyncMock(return_value=writepath_cfg(threshold=0.6))), \
          patch.object(pc.snippets_svc, "list_snippets",
                       AsyncMock(return_value=([], 0))), \
          patch.object(pc, "semantic_search_notes", search), \
@@ -470,9 +474,7 @@ async def test_write_path_labels_a_non_snippet_hit_with_its_kind():
     hits = [(0.72, fake_note(id=9, title="debounce helper", user_id=1, note_type="snippet")),
             (0.71, fake_note(id=7, title="Debounce dropped the trailing call", user_id=1, is_task=True, task_kind="issue"))]
     with patch.object(pc, "get_writepath_config",
-                      AsyncMock(return_value={"enabled": True, "threshold": 0.6,
-                                              "top_k": 3,
-                                              "rule_threshold": 0.72})), \
+                      AsyncMock(return_value=writepath_cfg(threshold=0.6))), \
          patch.object(pc.snippets_svc, "list_snippets",
                       AsyncMock(return_value=([], 0))), \
          patch.object(pc, "semantic_search_notes", AsyncMock(return_value=hits)), \

tests/test_services_reply_preferences.py

@@ -9,6 +9,9 @@ import re
 from unittest.mock import AsyncMock, MagicMock, patch
 
 M = "scribe.services.reply_preferences"
+# Its two numbers are resolved through the registry now (#4102), so the
+# settings reader to patch lives there rather than in the arm's own module.
+RS = "scribe.services.retrieval_surfaces"
 
 
 def _rule(rid, kind="preference"):
@@ -26,7 +29,7 @@ async def _run(hits, *, searched=True, raises=None):
 
     search_mock = AsyncMock(side_effect=search)
     with patch(f"{M}.semantic_search_rules", search_mock), \
-         patch(f"{M}.get_setting", AsyncMock(return_value="0.72")), \
+         patch(f"{RS}.get_setting", AsyncMock(return_value="0.72")), \
          patch(f"{M}.record_retrieval") as logged, \
          patch(f"{M}.record_rule_surfaced") as surfaced:
         out = await completion_preferences(7, project_id=3)
@@ -93,7 +96,7 @@ def test_its_bar_is_its_own_key_not_the_prompt_arm_s(monkeypatch):
 
     asked: list[str] = []
 
-    async def get_setting(user_id, key, default):
+    async def get_setting(user_id, key, default=""):
         asked.append(key)
         return default
 
@@ -101,16 +104,26 @@ def test_its_bar_is_its_own_key_not_the_prompt_arm_s(monkeypatch):
         kw["report"].update({"searched": True})
         return []
 
-    with patch(f"{M}.get_setting", AsyncMock(side_effect=get_setting)), \
+    with patch(f"{RS}.get_setting", AsyncMock(side_effect=get_setting)), \
          patch(f"{M}.semantic_search_rules", AsyncMock(side_effect=search)), \
          patch(f"{M}.record_retrieval"):
         asyncio.run(completion_preferences(7))
 
-    assert asked == [plugin_context.REPORTPREF_THRESHOLD_KEY]
-    assert plugin_context.REPORTPREF_THRESHOLD_KEY != plugin_context.PROMPTRULE_THRESHOLD_KEY, (
+    # Both numbers are its own since #4102 — a floor AND a budget — so the arm
+    # asks for two keys, and neither may be the prompt arm's.
+    from scribe.services.retrieval_surfaces import get_surface
+
+    mine = get_surface("report_preference")
+    assert asked == [mine.floor_key, mine.budget_key]
+    theirs = get_surface("prompt_rule")
+    assert mine.floor_key != theirs.floor_key, (
         "the two keys are the same string again, so the settings form has one "
         "dial driving two arms — which is the defect, whatever the value is"
     )
+    assert mine.floor_key == plugin_context.REPORTPREF_THRESHOLD_KEY, (
+        "the registry and the module constant disagree about this arm's key, "
+        "so the Settings form would write one and the arm would read the other"
+    )
 
 
 def test_the_query_assumes_no_particular_domain():

tests/test_session_context_ledger.py

@@ -108,14 +108,29 @@ def test_the_rules_ledger_survives_exactly_when_the_context_does(tmp_path):
     )
 
 
-def test_only_the_rule_ledger_is_cleared_and_the_note_ledgers_are_left(tmp_path):
-    """Scope, asserted rather than described.
+def test_the_note_ledgers_are_cleared_too_now_that_a_repeat_is_shown(tmp_path):
+    """The decision this test used to pin, reversed — and why it could be.
 
-    The same directory holds `.ids`, `.sync.ids` and `.derive.ids` for the note
-    arms. Whether a surfaced NOTE should come back after a compaction is a
-    different question with a different answer, and it is not being answered.
-    A `rm` glob over `<sid>.*` would pass every assertion in the test above
-    while silently deciding it.
+    It read: the note arms were deliberately left out of #3749, whether a
+    surfaced NOTE should come back after a compaction is a different question,
+    and a glob over `<sid>.*` would decide it by accident. That was right when
+    it was written, and the reason was the note arms' behaviour rather than the
+    note arms' nature: a note repeat was WITHHELD, so clearing their ledger
+    meant re-injecting whole menu lines the session had already been given.
+    Against that, leaving them was the cheaper mistake.
+
+    #4101 removed the premise. A note repeat is now rendered again with a
+    `seen` marker instead of dropped from the search, so the ledger no longer
+    decides whether a record is reachable — only whether its line says the
+    session has met it before. Across a compaction that marker becomes a false
+    statement: it tells a freshly-summarised session it has already seen a
+    record that is nowhere in its context. Keeping the ledger buys nothing and
+    asserts something untrue.
+
+    Kept as a named test rather than deleted, because the roster it guards
+    moved to tests/test_session_ledger_clear.py and what is worth keeping HERE
+    is the record that the answer changed, with the reason attached — a
+    deleted test takes the old decision's reasoning with it.
     """
     env = _env(tmp_path)
     sid = "sess-scope"
@@ -127,10 +142,9 @@ def test_only_the_rule_ledger_is_cleared_and_the_note_ledgers_are_left(tmp_path)
     _fire("compact", sid, env)
 
     assert not rules.exists(), "the rule ledger should have been cleared"
-    assert notes.exists() and sync.exists() and derive.exists(), (
-        "a note ledger was cleared too. The note arms were deliberately left "
-        "out of #3749 — clearing them is a decision about a different surface, "
-        "and a glob that takes them along makes it by accident."
+    assert not (notes.exists() or sync.exists() or derive.exists()), (
+        "a note ledger outlived the context it describes, so its records are "
+        "marked `seen` to a session that can no longer see them"
     )
 
 

tests/test_session_ledger_clear.py

@@ -0,0 +1,228 @@
+"""A compaction clears every session ledger, by convention not by list (#4101).
+
+WHY THIS EXISTS
+
+Milestone 386 established the claim: a ledger describes what a session HOLDS,
+so the events that destroy context must destroy it too, or the records it names
+become permanently unreachable mid-session. `scribe_session_context.sh`
+implemented that — for the rules ledger, by name.
+
+Five ledgers live in that directory and two were on the list. The note arms'
+three (`.ids`, `.sync.ids`, `.derive.ids`) were left, under a comment asserting
+this was "a decision rather than an oversight". It was not a decision, and the
+arms left out are the ones where it costs most:
+
+  - their exclusions are HARD — `exclude_ids` is passed into
+    `semantic_search_notes` itself, so a surfaced note leaves the result set
+    entirely, with no weaker rendering to fall back to the way #3750 gave a
+    repeated rule one;
+  - and they never AGE — #3751's TTL was added to the rules ledger only.
+
+Hard, permanent and never cleared: a note surfaced in a session's first minute
+is unreachable for the rest of it, through any number of compactions.
+
+WHAT THIS PINS
+
+The list was the bug, so the fix cannot be a longer list and neither can the
+test. Both sides are asserted:
+
+  1. BEHAVIOUR — the hook is run on a real `compact` event with all five
+     ledgers on disk, and all five are gone afterwards. Run rather than
+     grepped, because grepping for the names is the hand-maintained pattern
+     this step removes.
+  2. THE CONVENTION THE BEHAVIOUR RESTS ON — every per-session ledger any hook
+     builds is named `<sid>[.<kind>].ids`. That is what makes a sixth ledger
+     covered on the day it is written, and it is the assumption that would
+     rot silently, because a ledger named outside it simply never clears and
+     nothing says so.
+
+And the negative: `<sid>.unreached` is not a ledger of held context but a
+record that the instance could not be reached, and a glob that swept it away
+would make a hook forget an outage it is meant to report (#2932).
+"""
+import json
+import os
+import re
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+HOOKS = Path(__file__).resolve().parents[1] / "plugin" / "hooks"
+SESSION_START = HOOKS / "scribe_session_context.sh"
+DEFS = HOOKS / "scribe_defs.sh"
+
+# Every ledger the hooks write today, and where. Named here so a failure READS
+# as "this one survived", but never used to build the hook's own delete list —
+# the convention tests below are what keep this roster honest as it grows.
+LEDGERS = {
+    "scribe-priorart": (".ids", ".rules.ids", ".opened.ids", ".sync.ids",
+                        ".derive.ids"),
+    "scribe-autoinject": (".ids",),
+}
+
+
+def _swept_dirs() -> set[str]:
+    """The directories the SHIPPED hook sweeps, read from the hook itself.
+
+    Read rather than restated: a test carrying its own copy of the roster would
+    agree with itself forever, which is precisely the failure that let the
+    auto-inject ledger sit in a directory nothing cleared.
+    """
+    line = re.search(r'SCRIBE_LEDGER_DIRS="([^"]*)"', DEFS.read_text())
+    assert line, "SCRIBE_LEDGER_DIRS is gone; the clear has no roster"
+    return set(line.group(1).split())
+
+
+def _run_session_start(source: str, tmp: Path) -> Path:
+    """Run the SessionStart hook for real, with the ledger directories filled."""
+    for tool in ("bash", "jq"):
+        if shutil.which(tool) is None:
+            pytest.skip(f"hook runtime tool {tool!r} not installed")
+
+    for dirname, suffixes in LEDGERS.items():
+        state = tmp / dirname
+        state.mkdir(parents=True, exist_ok=True)
+        for suffix in suffixes:
+            (state / f"s1{suffix}").write_text("42\t1789600000\n")
+    # Not a ledger: an outage marker that must outlive the clear.
+    (tmp / "scribe-priorart" / "s1.unreached").write_text("1\n")
+
+    env = {"PATH": os.environ["PATH"], "HOME": str(tmp), "TMPDIR": str(tmp)}
+    out = subprocess.run(
+        ["bash", str(SESSION_START)],
+        input=json.dumps({"session_id": "s1", "source": source}),
+        capture_output=True, text=True, env=env, timeout=60,
+    )
+    assert out.returncode == 0, out.stderr
+    return tmp
+
+
+@pytest.mark.parametrize("source", ["compact", "clear"])
+def test_a_context_destroying_source_clears_every_ledger(source, tmp_path):
+    """The step, stated as behaviour: all of them, in both directories."""
+    root = _run_session_start(source, tmp_path)
+    survived = [f"{d}/s1{s}" for d, suffixes in LEDGERS.items()
+                for s in suffixes if (root / d / f"s1{s}").exists()]
+    assert not survived, (
+        f"{survived} survived a {source!r} that destroyed what they describe"
+    )
+
+
+@pytest.mark.parametrize("source", ["startup", "resume"])
+def test_a_source_that_kept_the_context_keeps_the_ledgers(source, tmp_path):
+    """The mirror error, and the more expensive one.
+
+    `resume` genuinely restores the context, so the ledger still describes what
+    the session holds; clearing there would re-surface every record after a
+    restore that lost nothing. A blanket glob makes over-clearing cheap to
+    write, which is exactly why this direction needs a test of its own.
+    """
+    root = _run_session_start(source, tmp_path)
+    for dirname, suffixes in LEDGERS.items():
+        for suffix in suffixes:
+            assert (root / dirname / f"s1{suffix}").exists(), (
+                f"{dirname}/s1{suffix} was cleared on {source!r}, which lost "
+                "no context"
+            )
+
+
+def test_the_outage_marker_is_not_swept_with_them(tmp_path):
+    """`.unreached` records that the instance was down, not what was surfaced.
+
+    Different lifetime, different question. #2932's whole point is that "we
+    checked and found nothing" and "we never managed to check" must stay
+    distinguishable, and a clear that took this file out would quietly answer
+    the second with the first.
+    """
+    root = _run_session_start("compact", tmp_path)
+    assert (root / "scribe-priorart" / "s1.unreached").exists()
+
+
+# ── the two assumptions the sweep rests on ─────────────────────────────────
+#
+# Both are checked against the hooks rather than trusted, because neither fails
+# loudly: a ledger outside them simply never clears, on the arm whose author had
+# no reason to know a convention existed.
+
+def _dir_vars(text: str) -> dict[str, str]:
+    """`var="${TMPDIR:-/tmp}/<name>"` → {var: name}, per script."""
+    return dict(re.findall(
+        r'(\w+)="\$\{TMPDIR:-/tmp\}/([A-Za-z0-9_-]+)"', text))
+
+
+def _session_paths(text: str):
+    """Every `$<var>/${safe_sid}<suffix>` a script composes."""
+    return re.findall(r'\$(\w+)"?/\$\{safe_sid\}([A-Za-z0-9_.]*)', text)
+
+
+def test_every_directory_holding_a_ledger_is_one_the_clear_visits():
+    """The failure that shipped once already, in the same step that fixed it.
+
+    The first cut swept `scribe-priorart` alone. Every ledger NAMED in the
+    hooks was there, so it read as complete — and `scribe_autoinject.sh` keeps
+    its note ledger in `scribe-autoinject`, which meant the arm that fires most
+    was the only one still carrying the bug. Nothing said so: the clear ran,
+    found nothing to remove, and exited 0.
+    """
+    swept = _swept_dirs()
+    offenders = []
+    for script in sorted(HOOKS.glob("*.sh")):
+        text = script.read_text()
+        dirs = _dir_vars(text)
+        for var, suffix in _session_paths(text):
+            if not suffix.endswith(".ids"):
+                continue
+            where = dirs.get(var)
+            if where not in swept:
+                offenders.append(f"{script.name}: ${var} -> {where or '?'}")
+
+    assert not offenders, (
+        "these ledgers live in directories the compaction clear never visits, "
+        f"so they outlive the context they describe: {offenders}. Add the "
+        "directory to SCRIBE_LEDGER_DIRS in scribe_defs.sh."
+    )
+
+
+def test_every_session_file_in_a_swept_directory_follows_the_convention():
+    """The other half: the sweep matches `.ids`, so a ledger must be named it.
+
+    Stated as its own test because the two assumptions fail differently — this
+    one lets a ledger sit in the right directory and still never clear.
+    """
+    # Session files in a swept directory that are NOT per-session ledgers.
+    NOT_LEDGERS = {".unreached"}
+
+    swept = _swept_dirs()
+    offenders = []
+    for script in sorted(HOOKS.glob("*.sh")):
+        text = script.read_text()
+        dirs = _dir_vars(text)
+        for var, suffix in _session_paths(text):
+            if dirs.get(var) not in swept:
+                continue          # a different directory, a different question
+            if suffix in NOT_LEDGERS or suffix.endswith(".ids"):
+                continue
+            offenders.append(f"{script.name}: ${var}/${{safe_sid}}{suffix}")
+
+    assert not offenders, (
+        "these session files sit in a swept directory but clear on no "
+        f"compaction, because the sweep matches `.ids`: {offenders}"
+    )
+
+
+def test_the_clear_is_derived_and_not_a_list_of_names():
+    """The regression that would look like a fix.
+
+    Appending an `rm -f` per ledger passes every behavioural test above while
+    rebuilding the trap for the next one. The property worth keeping is that
+    the hook names no ledger at all.
+    """
+    sh = SESSION_START.read_text()
+    block = sh.split('case "$source" in')[1].split("esac")[0]
+    assert "scribe_clear_session_ledgers" in block
+    for suffix in {s for suffixes in LEDGERS.values() for s in suffixes}:
+        assert suffix not in block, (
+            f"the clear names {suffix} again — a list, not a convention"
+        )

tests/test_settings_defaults_agree.py

@@ -20,9 +20,12 @@ string equals the Python default. Retuning either stays free as long as both
 move — which is the point, because these are tuning values and #3853 moved one
 of them the day this was written.
 
-Both sides are read from SOURCE rather than imported. The Vue file cannot be
-imported at all, and reading the Python constant through an import would tie
-this to module-load side effects it has no interest in.
+The Vue side is read from SOURCE, because that file cannot be imported at all.
+The Python side is read from source for a loose constant and IMPORTED for a
+registry surface — the registry is a plain table of frozen dataclasses with
+nothing to trigger on import, and importing it means this guard checks the value
+the server will actually resolve rather than a literal that happens to look
+right.
 
 It cannot check that the form WRITES the right key — that is behaviour, and
 the keys are asserted where they are built. It catches the drift that has no
@@ -39,20 +42,29 @@ ROOT = pathlib.Path(__file__).resolve().parents[1]
 _SERVICES = ROOT / "src" / "scribe" / "services"
 _VUE = ROOT / "frontend" / "src" / "views" / "SettingsView.vue"
 
-# (services module, python constant, vue ref). Hand-written because the
-# pairing is an editorial fact — the names do not share a convention either
-# side could derive — but every entry is asserted to EXIST on both sides, so a
-# rename fails loudly here rather than silently dropping that threshold from
-# the check.
-_PAIRS = (
-    ("plugin_context.py", "AUTOINJECT_DEFAULT_THRESHOLD", "kbInjectThreshold"),
-    ("plugin_context.py", "WRITEPATH_DEFAULT_THRESHOLD", "kbWritePathThreshold"),
-    ("plugin_context.py", "RULEHINT_DEFAULT_THRESHOLD", "kbRuleHintThreshold"),
-    ("plugin_context.py", "TOOLRULE_DEFAULT_THRESHOLD", "kbToolRuleThreshold"),
-    ("plugin_context.py", "PROMPTRULE_DEFAULT_THRESHOLD", "kbPromptRuleThreshold"),
-    ("plugin_context.py", "REPORTPREF_DEFAULT_THRESHOLD", "kbReportPrefThreshold"),
+# THE SIX RETRIEVAL FLOORS now live in one registry (#4102), so their side of
+# the pairing is a SURFACE NAME rather than a module constant. That is strictly
+# better for this guard: the surface name is also the telemetry source, so a row
+# here names the same arm the readout does, and a floor that moved cannot be
+# checked against a stale constant that happened to keep its old value.
+_SURFACE_PAIRS = (
+    ("auto_inject", "kbInjectThreshold"),
+    ("write_path", "kbWritePathThreshold"),
+    ("write_path_rule", "kbRuleHintThreshold"),
+    ("pre_tool_rule", "kbToolRuleThreshold"),
+    ("prompt_rule", "kbPromptRuleThreshold"),
+    ("report_preference", "kbReportPrefThreshold"),
+)
+
+# (services module, python constant, vue ref) for the defaults that are NOT
+# retrieval surfaces. Hand-written because the pairing is an editorial fact —
+# the names share no convention either side could derive — and asserted to
+# exist on both sides, so a rename fails loudly rather than silently dropping
+# that threshold from the check.
+_CONSTANT_PAIRS = (
     # The plan gate (milestone 415): it blocks a create, so a form showing a
-    # looser bar than the one in force would be the more misleading drift.
+    # looser bar than the one in force would be the more misleading drift. Not
+    # a push surface, so it has no registry entry and keeps the older shape.
     ("dedup.py", "PLAN_MATCH_DEFAULT_THRESHOLD", "kbPlanMatchThreshold"),
 )
 
@@ -80,14 +92,42 @@ def _vue_default(ref_name: str) -> float:
     return float(m.group(1))
 
 
-@pytest.mark.parametrize(("module", "constant", "ref_name"), _PAIRS,
-                         ids=[p[1] for p in _PAIRS])
-def test_the_form_shows_the_default_the_server_uses(module, constant, ref_name):
-    """An untouched control must render the bar actually in force."""
-    server, form = _python_default(module, constant), _vue_default(ref_name)
+def _assert_agrees(server: float, form: float, ref_name: str, what: str) -> None:
     assert form == server, (
         f"SettingsView shows {form} for {ref_name} while the server defaults "
-        f"to {server} ({constant}). An operator who has never set this reads "
-        f"the form as the value in force, so the two must move together — "
-        f"retune both, or neither."
+        f"to {server} ({what}). An operator who has never set this reads the "
+        f"form as the value in force, so the two must move together — retune "
+        f"both, or neither."
     )
+
+
+@pytest.mark.parametrize(("surface", "ref_name"), _SURFACE_PAIRS,
+                         ids=[p[0] for p in _SURFACE_PAIRS])
+def test_the_form_shows_the_floor_the_surface_uses(surface, ref_name):
+    """An untouched control must render the bar actually in force."""
+    from scribe.services.retrieval_surfaces import get_surface
+
+    _assert_agrees(get_surface(surface).floor_default, _vue_default(ref_name),
+                   ref_name, f"{surface} floor")
+
+
+def test_every_tunable_surface_has_a_control():
+    """Rule 25/27: a number an operator may need different has a UI or it is
+    not shipped. Derived from the registry, so a seventh surface arrives here
+    as a failure rather than as a setting only the model can reach."""
+    from scribe.services.retrieval_surfaces import surface_names
+
+    covered = {s for s, _ref in _SURFACE_PAIRS}
+    missing = [n for n in surface_names() if n not in covered]
+    assert not missing, (
+        f"these surfaces are tunable with no Settings control: {missing}. "
+        "Add the control and its row, or say in _SURFACE_PAIRS why it has none."
+    )
+
+
+@pytest.mark.parametrize(("module", "constant", "ref_name"), _CONSTANT_PAIRS,
+                         ids=[p[1] for p in _CONSTANT_PAIRS])
+def test_the_form_shows_the_default_the_server_uses(module, constant, ref_name):
+    """Same claim, for the defaults that are not retrieval surfaces."""
+    _assert_agrees(_python_default(module, constant), _vue_default(ref_name),
+                   ref_name, constant)

tests/test_write_path_trigger.py

@@ -6,6 +6,7 @@ source, and the two ways this must stay silent. Plus the plugin hook contract
 a PreToolUse hook that returns a permission decision would be able to block the
 operator's edit, which this feature must never do.
 """
+import contextlib
 import json
 import re
 import subprocess
@@ -13,7 +14,30 @@ from pathlib import Path
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
-from tests.helpers import fake_note, http_sink
+from tests.helpers import fake_note, http_sink, writepath_cfg
+
+
+@contextlib.contextmanager
+def _stored_settings(stored):
+    """Patch BOTH readers, because one call now uses two (#4102).
+
+    `get_writepath_config` reads its `enabled` switch through
+    `plugin_context.get_setting` and all six tunable numbers through
+    `retrieval_surfaces.get_setting`. Patching only the first leaves the numbers
+    talking to a real database — which in a unit job is a connection error, and
+    in an integration job is worse: the test would pass or fail on whatever the
+    instance happened to have stored.
+    """
+    from scribe.services import plugin_context as pc
+    from scribe.services import retrieval_surfaces as rs
+
+    def _side(uid, k, d=""):
+        return stored.get(k, d)
+
+    with patch.object(pc, "get_setting", AsyncMock(side_effect=_side)), \
+         patch.object(rs, "get_setting", AsyncMock(side_effect=_side)):
+        yield
+
 
 PLUGIN = Path(__file__).resolve().parents[1] / "plugin"
 HOOK = PLUGIN / "hooks" / "scribe_prior_art.sh"
@@ -31,9 +55,7 @@ def _cfg(**over):
     # missing key raises inside its fail-open except and turns the arm into a
     # silent no-op — which is indistinguishable from it working and finding
     # nothing.
-    base = {"enabled": True, "threshold": 0.68, "top_k": 3, "rule_threshold": 0.72}
-    base.update(over)
-    return base
+    return writepath_cfg(**over)
 
 
 # The semantic arm ignores payloads carrying less than WRITEPATH_MIN_CODE_CHARS
@@ -310,9 +332,23 @@ async def test_semantic_arm_only_asks_for_the_budget_the_place_arm_left():
 
 
 @pytest.mark.asyncio
-async def test_session_dedup_excludes_ids_from_the_reuse_arms():
+async def test_session_dedup_marks_the_reuse_arms_rather_than_silencing_them():
     """exclude_ids governs the REUSE classes — nearby and semantic. (The sync
-    class has its own channel; see the tests above.)"""
+    class has its own channel; see the tests above.)
+
+    WHAT CHANGED AND WHY (#4101). This used to assert the opposite: the nearby
+    hit was dropped and its id pushed into the search's `exclude_ids`. That was
+    #3750's defect on the note arms — the second time a record was the best
+    answer, the session got silence, which reads exactly like "nothing is
+    recorded here". Now the repeat is rendered with a `seen` marker, and the
+    ledger never reaches the query, so the score the search reports describes
+    the bar rather than a candidate set the caller had already edited.
+
+    Marked on BOTH reuse arms, which is what this asserts: one menu with two
+    rules — `seen` on the semantic hits, silence on the nearby ones — would
+    make the marker read as a complete account of what the session has met,
+    when it would only cover half the lines.
+    """
     from scribe.services import plugin_context as pc
 
     async def _listing(uid, **kw):
@@ -327,8 +363,15 @@ async def test_session_dedup_excludes_ids_from_the_reuse_arms():
          patch.object(pc, "semantic_search_notes", search), \
          patch.object(pc, "record_retrieval", MagicMock()):
         out = await pc.build_write_path_hint(1, "src/x.py", code=REAL_CODE, exclude_ids=[12])
-    # The nearby hit was already surfaced this session → dropped, not repeated.
-    assert out["note_ids"] == []
+    assert out["note_ids"] == [12]
+    assert "seen" in next(
+        line for line in out["context"].splitlines() if "#12" in line
+    )
+    # #12 IS in this call's `exclude_ids`, and that is the other rule working:
+    # the place arm has just listed it, so the semantic arm must not list it
+    # again. What must never reach the query is the LEDGER, which is asserted
+    # on its own in tests/test_ledger_references_not_silence.py against a
+    # record this call has not otherwise rendered.
     assert 12 in search.await_args.kwargs["exclude_ids"]
 
 
@@ -402,11 +445,10 @@ async def test_sync_surfacing_is_measured_under_its_own_usage_source():
 
 
 @pytest.mark.asyncio
-async def test_config_has_its_own_switch_and_threshold_but_shares_top_k():
+async def test_config_has_its_own_switch_threshold_and_inherited_budget():
     from scribe.services import plugin_context as pc
     stored = {pc.WRITEPATH_ENABLED_KEY: "false"}
-    with patch.object(pc, "get_setting",
-                      AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+    with _stored_settings(stored):
         cfg = await pc.get_writepath_config(1)
     # Its own switch is off while auto-inject stays on...
     assert cfg["enabled"] is False
@@ -415,8 +457,12 @@ async def test_config_has_its_own_switch_and_threshold_but_shares_top_k():
     # made unrelated code — including `x = 1` at 0.58 — clear the bar.
     assert cfg["threshold"] == pc.WRITEPATH_DEFAULT_THRESHOLD
     assert cfg["threshold"] > pc.AUTOINJECT_DEFAULT_THRESHOLD
-    # ...and top_k is still shared: "how many titles at once" means the same
-    # thing on both surfaces.
+    # ...and the budget is INHERITED rather than shared (#4102). This arm has
+    # its own key now, because it fires before every Write and Edit while
+    # auto-inject fires once a turn, so the same number buys very different
+    # amounts of attention. Unset, it still reads auto-inject's — which is what
+    # stops the split from silently resetting an install that had tuned the
+    # knob when it was shared.
     assert cfg["top_k"] == pc.AUTOINJECT_DEFAULT_TOP_K
 
 
@@ -428,8 +474,7 @@ async def test_writepath_threshold_is_operator_tunable_and_clamped():
 
     async def _cfg_with(raw):
         stored = {pc.WRITEPATH_THRESHOLD_KEY: raw}
-        with patch.object(pc, "get_setting",
-                          AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+        with _stored_settings(stored):
             return await pc.get_writepath_config(1)
 
     assert (await _cfg_with("0.9"))["threshold"] == 0.9
@@ -453,8 +498,7 @@ async def test_the_rule_arm_has_its_own_tunable_bar():
 
     async def _cfg_with(raw):
         stored = {pc.RULEHINT_THRESHOLD_KEY: raw}
-        with patch.object(pc, "get_setting",
-                          AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+        with _stored_settings(stored):
             return await pc.get_writepath_config(1)
 
     assert (await _cfg_with("0.8"))["rule_threshold"] == 0.8
@@ -473,8 +517,7 @@ async def test_the_two_write_path_bars_are_independent():
     from scribe.services import plugin_context as pc
 
     stored = {pc.WRITEPATH_THRESHOLD_KEY: "0.90", pc.RULEHINT_THRESHOLD_KEY: "0.61"}
-    with patch.object(pc, "get_setting",
-                      AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+    with _stored_settings(stored):
         cfg = await pc.get_writepath_config(1)
 
     assert cfg["threshold"] == 0.90
@@ -495,8 +538,7 @@ async def test_the_two_act_arms_read_independent_rule_bars():
     from scribe.services import plugin_context as pc
 
     stored = {pc.RULEHINT_THRESHOLD_KEY: "0.75", pc.TOOLRULE_THRESHOLD_KEY: "0.61"}
-    with patch.object(pc, "get_setting",
-                      AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+    with _stored_settings(stored):
         cfg = await pc.get_writepath_config(1)
 
     assert cfg["rule_threshold"] == 0.75
@@ -515,8 +557,7 @@ async def test_a_garbage_command_bar_falls_back_to_its_own_default():
     from scribe.services import plugin_context as pc
 
     stored = {pc.TOOLRULE_THRESHOLD_KEY: "banana"}
-    with patch.object(pc, "get_setting",
-                      AsyncMock(side_effect=lambda uid, k, d: stored.get(k, d))):
+    with _stored_settings(stored):
         cfg = await pc.get_writepath_config(1)
 
     assert cfg["tool_rule_threshold"] == pc.TOOLRULE_DEFAULT_THRESHOLD
@@ -1264,8 +1305,16 @@ async def test_stamping_needs_named_shapes_and_a_recent_pull():
 async def test_a_pulled_snippet_already_seen_is_evidence_not_menu():
     """The pulled-then-written flow IS the dedup-excluded flow: the hint offered
     #7 earlier (so it sits in exclude_ids), the session pulled it, and now
-    writes code resembling it. #7 must be scored for this payload — and handed
-    to the stamp as resemblance — without being re-listed in the menu."""
+    writes code resembling it. #7 must be scored for this payload and handed to
+    the stamp as resemblance.
+
+    THE MENU HALF INVERTED AT #4101. This asserted that #7 was evidence and NOT
+    menu — scored for the stamp, kept out of the lines. That followed from the
+    ledger being a hard exclusion; it is now a marker, so #7 is both, and the
+    `limit` no longer needs widening for it because nothing is dropped after
+    the search. What survives unchanged is the part the stamp depends on: the
+    pulled id stays in the query and its score reaches `resembles`.
+    """
     from scribe.services import plugin_context as pc
     search = AsyncMock(return_value=[(0.91, fake_note(id=7, title="pulled", user_id=1, note_type="snippet")), (0.80, fake_note(id=8, title="fresh", user_id=1, note_type="snippet"))])
     stamp = AsyncMock(return_value=[{
@@ -1283,15 +1332,20 @@ async def test_a_pulled_snippet_already_seen_is_evidence_not_menu():
             1, "src/x.py", code=REAL_CODE, project_id=4, exclude_ids=[7],
             stamp_shapes=[("sym", "debounce")], repo_key="git.example.com/a/b",
         )
-    # The query kept #7 eligible (and widened the budget by one for it)...
+    # The query kept #7 eligible, and needs no extra budget for it now that
+    # nothing is dropped between the search and the menu.
     kw = search.call_args.kwargs
     assert 7 not in kw["exclude_ids"]
-    assert kw["limit"] == 4
-    # ...but the menu still honours the session dedup.
-    assert out["note_ids"] == [8]
-    assert "#7" not in "\n".join(
-        line for line in out["context"].splitlines() if "[similar" in line
-    )
+    assert kw["limit"] == 3
+    # ...and the menu carries it, marked.
+    seven = next(line for line in out["context"].splitlines() if "#7" in line)
+    assert "seen" in seven
+    # #8 (0.80) now falls OUTSIDE the margin band, because #7 (0.91) anchors it
+    # at 0.81 instead of being filtered out first. That is the point rather than
+    # a casualty: the band measures distance from the best answer, and the best
+    # answer here is #7 — suppressing it used to promote a materially weaker hit
+    # into a slot it had not earned, with nothing in the output saying so.
+    assert out["note_ids"] == [7]
     # The stamp saw the pull and the resemblance score for this payload.
     skw = stamp.call_args.kwargs
     assert skw["pulled"] == {7: skw["pulled"][7]}
@@ -1670,9 +1724,47 @@ async def _write_path_row(rec, **kwargs):
 async def test_a_record_this_arm_withheld_itself_is_not_a_near_miss():
     """The defect: the row's count is POST this arm's filter and the score was
     captured PRE it, so a withheld record is indistinguishable from one the bar
-    rejected — while scoring higher than anything the bar ever let through."""
+    rejected — while scoring higher than anything the bar ever let through.
+
+    REACHED DIFFERENTLY SINCE #4101, and that is the news. The ledger used to
+    produce this case and no longer can: a repeat comes back from the search
+    and is rendered, so nothing is dropped and `best_available` describes the
+    bar alone. What still produces it is the one post-search filter left — a
+    PULLED record that this same call already listed by place. It stays in the
+    query because `resembles` needs its score, and is dropped from the menu
+    because it is already on it, which is exactly the pre/post split.
+
+    The property is unchanged and worth as much as it ever was; only the setup
+    that exhibits it moved. Written this way rather than deleted, because the
+    filter is still there and an arm that reported a score for it would be
+    making the same false claim about the bar.
+    """
+    from scribe.services import plugin_context as pc
     rec = MagicMock()
-    row = await _write_path_row(rec, exclude_ids=[7])
+    # Recorded at a sibling file → listed by PLACE in this same call, and
+    # pulled this session → kept in the query as resemblance evidence.
+    async def _listing(uid, **kw):
+        if kw["path"] == "src":
+            return ([_snippet_item(7, "already listed by place")], 1)
+        return ([], 0)
+
+    with patch.object(pc, "get_writepath_config", AsyncMock(return_value=_cfg())), \
+         patch.object(pc.snippets_svc, "list_snippets", _listing), \
+         patch.object(pc, "record_retrieval", rec), \
+         patch.object(pc, "owner_names_for", AsyncMock(return_value={})), \
+         patch.object(pc.shape_ledger_svc, "recent_pulls",
+                      AsyncMock(return_value={7: _ts()})), \
+         patch.object(pc.shape_ledger_svc, "stamp_write_path_instances",
+                      AsyncMock(return_value=[])), \
+         patch.object(pc, "semantic_search_notes",
+                      _search_reporting(0.9, fake_note(
+                          id=7, title="scored", user_id=1, note_type="snippet"))):
+        await pc.build_write_path_hint(
+            1, "src/x.py", code=REAL_CODE,
+            stamp_shapes=[("sym", "debounce")],
+        )
+    row = next(c for c in rec.call_args_list
+               if c.kwargs["source"] == "write_path")
 
     assert row.kwargs["results"] == [], "the hit was withheld, so nothing shown"
     assert row.kwargs["best_available"] is None, (
@@ -1682,6 +1774,27 @@ async def test_a_record_this_arm_withheld_itself_is_not_a_near_miss():
     )
 
 
+@pytest.mark.asyncio
+async def test_a_ledger_repeat_no_longer_produces_that_case_at_all():
+    """The other direction, and the reason the setup above had to move.
+
+    A record on the session ledger now clears the search, is rendered with a
+    marker, and is counted in `suppressed` — so nothing is withheld and the
+    reported score describes the bar. Pinned because the tempting way to keep
+    the old test passing would have been to null the score whenever the ledger
+    matched, which would delete the measurement #3670 was built for on exactly
+    the calls where the bar is most worth reading.
+    """
+    rec = MagicMock()
+    row = await _write_path_row(rec, exclude_ids=[7])
+
+    assert row.kwargs["results"] == [], "a repeat is not a fresh result"
+    assert row.kwargs["suppressed"] == 1, "and it is counted rather than lost"
+    assert row.kwargs["best_available"] == 0.9, (
+        "nothing was withheld, so the reported score describes the bar"
+    )
+
+
 @pytest.mark.asyncio
 async def test_a_call_that_withheld_nothing_still_reports_what_the_bar_refused():
     """The other half, and what stops the fix being 'never report it'.