fix(telemetry): a search that never ran is not a decline (#3765)

`best_available_score` was added by #3670 so a bar could be judged from
what it rejected, and it arrived null on four unrelated causes: the corpus
offered nothing, the query was empty, the embedder was down, or the
DATABASE QUERY FAILED. Only the first is a measurement. The fourth is the
#2663 shape — a swallowed failure rendering as a clean zero — inside the
field added to fix an instance of the #2663 shape.

Found while trying to explain why reuse_slot returned nothing on 45 of 45
calls, and auto_inject on 153 of 161. That investigation is still open;
what it established first is that the readout could not answer it.

THE FIX IS NOT A NEW COLUMN. A call that never searched writes no row, so
every remaining null means one thing: searched, and nothing came close.
That is the convention the pre-tool arm already follows for a blank
command — "a row here would report a call that never happened and drag the
clear-rate down with phantom declines" — extended from the case a caller
can see in advance to the ones only the search knows about.

Both searches stamp `report["searched"]` FALSE before anything can return
and True only where a real result set exists, so every early return leaves
it false. It has to be the first thing done to the dict: a return added
above that line would leave the key absent.

ABSENT IS A THIRD STATE AND IT DEFAULTS TO TRUE. A caller that passes no
report cannot know, and the safe reading there is the old behaviour. Only
a real search can report False, so absent means "nobody asked" and never
"it failed" — which is also why 66 existing mocked searches across twelve
test files keep working unchanged rather than being rewritten to simulate
a flag they do not care about.

A FAILURE IS NOT MADE INVISIBLE. semantic_search_notes already logs a
WARNING on a query failure, which is where a broken search belongs: a
counter cannot say "I am broken" without a reader already trusting it.

Three tests, and the middle one is what makes them discriminate — a
blanket `return` passes the first and fails the second, because a call
that searched and came back empty is the only evidence a threshold is too
high (#3497).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011cPyzNnegXHr5iRMzzy5KJ

src/scribe/mcp/tools/search.py

@@ -128,6 +128,7 @@ async def search(
         project_id=project_id or None, is_task=is_task, results=raw,
         duration_ms=(time.perf_counter() - t0) * 1000.0,
         best_available=report.get("best_available_score"),
+        searched=bool(report.get("searched", True)),
     )
     owners = await owner_names_for(
         {int(note.user_id) for _s, note in raw if note.user_id != uid}
@@ -185,6 +186,16 @@ async def retrieval_telemetry(days: int = 30) -> dict:
     "nothing came close"; a 0.0 there would be a claim about the corpus
     invented out of a caller's silence.
 
+    A NULL HERE NOW MEANS ONE THING, which it did not at first. A semantic
+    search returns nothing three ways WITHOUT having run — an empty query, an
+    unavailable embedder, and a failed database query — and each used to write
+    a row indistinguishable from a ranker that declined (#3765). Those calls no
+    longer write a row at all, on the same reasoning that already keeps a blank
+    command out of the log: a row there reports a call that never happened and
+    drags the clear rate down with phantom declines. So a null is "searched,
+    and nothing came close", and a broken search shows up as a WARNING in the
+    application log rather than as a quiet zero in here.
+
     THERE IS NO `cleared_threshold` ANY MORE, and if you remember one, that
     memory is of a tautology (#3670). The search applies the bar before
     returning, so every returned result cleared it by construction and a call

src/scribe/routes/search.py

@@ -58,6 +58,7 @@ async def search_route():
         project_id=project_id, is_task=is_task, results=results,
         duration_ms=(time.perf_counter() - t0) * 1000.0,
         best_available=report.get("best_available_score"),
+        searched=bool(report.get("searched", True)),
     )
     owners = await owner_names_for(
         {int(note.user_id) for _s, note in results if note.user_id != uid}

src/scribe/services/embeddings.py

@@ -492,6 +492,14 @@ async def semantic_search_notes(
     the only figure that survives a call returning nothing, and therefore the
     only one a bar can be judged from (#3670).
 
+    It also sets `report["searched"]`: False before anything can return, True
+    only where a real result set exists. So an empty query, an unavailable
+    embedder and a failed database query all leave it FALSE, and a caller can
+    tell a search that found nothing from one that never ran. A caller logging
+    telemetry must check it — recording a failed search as a zero-result call
+    reports a decline the ranker never made (#3765). ABSENT means no search
+    touched the dict at all, which is a stand-in in a test, not a real call.
+
     `note_type` narrows to a record kind, or several (e.g. "snippet", or
     ("snippet", "note")), for callers that want prior art rather than everything
     embedded.
@@ -526,6 +534,13 @@ async def semantic_search_notes(
 
     Returns an empty list if the embedder is unavailable or on any error.
     """
+    # Stamped FALSE before anything can return, flipped True only where a real
+    # result set exists (#3765). Every early return below leaves it false, so a
+    # caller can tell a search that found nothing from one that never ran. It
+    # has to be the first thing done to `report`: a return added above this
+    # line would leave the key ABSENT, which reads as "no caller asked".
+    if report is not None:
+        report["searched"] = False
     if not query or not query.strip():
         return []
     try:
@@ -636,6 +651,13 @@ async def semantic_search_notes(
     # The best score anything reached, bar or no bar. Recorded BEFORE the
     # filter because a call that returns nothing is exactly when it matters.
     if report is not None:
+        # `searched` is what stops a null score meaning four things (#3765).
+        # Every early return above — empty query, embedder down, and the broad
+        # `except` around the query itself — leaves this key ABSENT, so a
+        # caller can tell "I looked and there was nothing" from "I never
+        # looked" and from "the query failed". Set here, at the one point past
+        # which a real result set exists.
+        report["searched"] = True
         report["best_available_score"] = scored[0][0] if scored else None
     scored = [pair for pair in scored if pair[0] >= threshold]
     if not demote_superseded:
@@ -801,6 +823,14 @@ async def semantic_search_rules(
     the only figure that survives a call returning nothing, and therefore the
     only one a bar can be judged from (#3670).
 
+    It also sets `report["searched"]`: False before anything can return, True
+    only where a real result set exists. So an empty query, an unavailable
+    embedder and a failed database query all leave it FALSE, and a caller can
+    tell a search that found nothing from one that never ran. A caller logging
+    telemetry must check it — recording a failed search as a zero-result call
+    reports a decline the ranker never made (#3765). ABSENT means no search
+    touched the dict at all, which is a stand-in in a test, not a real call.
+
     Scoped by OWNERSHIP — a rule is the caller's if they own its rulebook or
     its project. Deliberately not filtered to what currently BINDS a given
     project: this answers "is there a rule about this", which a person asking
@@ -828,6 +858,9 @@ async def semantic_search_rules(
     from scribe.models.project import Project
     from scribe.models.rulebook import Rule, Rulebook, RulebookTopic
 
+    # See the sibling search: stamped before anything can return (#3765).
+    if report is not None:
+        report["searched"] = False
     if not query or not query.strip():
         return []
     try:
@@ -874,6 +907,8 @@ async def semantic_search_rules(
             best[rule.id] = (score, rule)
     ranked = sorted(best.values(), key=lambda pair: pair[0], reverse=True)
     if report is not None:
+        # See the sibling search: absent means the search never ran (#3765).
+        report["searched"] = True
         report["best_available_score"] = ranked[0][0] if ranked else None
     return [pair for pair in ranked if pair[0] >= threshold][:limit]
 

src/scribe/services/plugin_context.py

@@ -484,6 +484,7 @@ async def _reserve_slot_for_reuse(
         threshold=cfg["threshold"], limit=1, project_id=project_id,
         is_task=None, results=reuse,
         best_available=_rep.get("best_available_score"),
+        searched=bool(_rep.get("searched", True)),
         duration_ms=(time.perf_counter() - _t0) * 1000.0,
     )
     # Verify the kind rather than trusting the query that asked for it, and
@@ -552,6 +553,7 @@ async def build_autoinject_hint(
         threshold=cfg["threshold"], limit=cfg["top_k"],
         project_id=(project_id or None), is_task=None, results=hits,
         best_available=_rep_ai.get("best_available_score"),
+        searched=bool(_rep_ai.get("searched", True)),
         duration_ms=(time.perf_counter() - t0) * 1000.0,
     )
     if not hits:
@@ -1046,6 +1048,7 @@ async def build_write_path_hint(
             best_available=(
                 None if withheld_here else _rep_wp.get("best_available_score")
             ),
+            searched=bool(_rep_wp.get("searched", True)),
             duration_ms=(time.perf_counter() - t0) * 1000.0,
         )
         if hits:
@@ -1342,6 +1345,7 @@ async def build_write_path_hint(
             project_id=project_id,
             is_task=None, results=fresh, duration_ms=rule_ms,
             best_available=_rep_wpr.get("best_available_score"),
+            searched=bool(_rep_wpr.get("searched", True)),
             # What the ranker found and this session had already been told.
             # Without it a zero row cannot say whether the bar was too high or
             # the reader was simply ahead of it — and only the first is a
@@ -1449,6 +1453,7 @@ async def build_tool_rule_hint(
             project_id=project_id,
             is_task=None, results=fresh, duration_ms=duration_ms,
             best_available=_rep_ptr.get("best_available_score"),
+            searched=bool(_rep_ptr.get("searched", True)),
             # See the sibling arm. It matters more here: this arm fires on every
             # Bash call, so a long session excludes its way to an all-zero row
             # and the threshold looks wrong when nothing about it is.

src/scribe/services/retrieval_telemetry.py

@@ -135,6 +135,7 @@ def record_retrieval(
     duration_ms: float | None = None,
     suppressed: int | None = None,
     best_available: float | None = None,
+    searched: bool = True,
 ) -> None:
     """Fire-and-forget: record one retrieval call.
 
@@ -146,9 +147,35 @@ def record_retrieval(
     provide. retrieval_logs is not restored at all, so it has no such hazard,
     and `source` already distinguishes the surfaces.
 
+    `searched=False` WRITES NO ROW, and that is the point rather than an
+    optimisation. A semantic search has three ways to return nothing without
+    having run — an empty query, an unavailable embedder, and the broad
+    `except` around the query itself — and each one currently arrives here
+    looking exactly like a ranker that declined. Logging it would report a
+    decline nobody made, drag `zero_result_calls` down with phantom evidence
+    about a threshold, and leave `best_available_score` null for a reason that
+    has nothing to do with the corpus. That last ambiguity is #3765: the field
+    added to judge a bar was null on four unrelated causes, one of them a
+    swallowed failure, and no reader could tell them apart.
+    Dropping the row is what makes the remaining nulls mean ONE thing —
+    "searched, and there was nothing".
+
+    The same convention already governs the pre-tool arm: a blank command costs
+    no embedding query, so it writes no row, because "a row here would report a
+    call that never happened and drag the clear-rate down with phantom
+    declines". This extends it from a case the caller could see in advance to
+    the ones only the search knows about.
+
+    A FAILURE IS NOT MADE INVISIBLE BY THIS. `semantic_search_notes` logs a
+    WARNING on a query failure, which is where a broken search belongs — a
+    counter cannot say "I am broken" without a reader already trusting it.
+
     Builds the payload inline (synchronously) then schedules the insert so the
     caller returns immediately. Never raises — telemetry must not affect search.
     """
+    if not searched:
+        return
+
     try:
         payload = _build_payload(
             user_id=user_id,