docs(6209): twelve more test files say which behaviour they pin

shape ledger, MCP projects/search/rulebooks tools, backup, chunking,
plugin context, derived mirror, rule band, shape form gate, plugin
version mint and note usage tests drop issue, milestone and rule numbers,
dates and one-install figures from docstrings, comments and messages.
Three shape-form-gate test names that told the discovery story now name
the property: a registry module's helpers are not service functions, the
divergence gate silences only a family contradiction, and callable helpers
beside a callable canon still prompt. The rulebook tool-count comment that
logged each milestone's additions is replaced by the reason it is a count.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_services_plugin_context.py

@@ -88,7 +88,7 @@ async def test_build_autoinject_hint_titles_only_with_margin_gate():
     # Telemetry fired for BOTH retrievals this path runs: the scored menu and
     # the reuse-slot query competing against it. The slot's query used to be
     # the one unlogged retrieval on this path — the hit it displaced was in
-    # retrieval_logs, the query that displaced it was not (#2463).
+    # retrieval_logs, and the query that displaced it must be too.
     sources = [c.kwargs["source"] for c in rec.call_args_list]
     assert sources == ["auto_inject", "reuse_slot", "lesson_slot"]
 
@@ -127,7 +127,7 @@ async def test_build_session_context_includes_project_when_scoped():
     # No design system on the project -> no design block at all. An install with
     # none is the ordinary case, not a degraded one.
     assert "## Design system" not in out["context"]
-    # Live state only (decision #4027): how to work with Scribe is the
+    # Live state only: how to work with Scribe is the
     # using-scribe skill's to say. A restated reflex here is a copy that drifts.
     assert 'content_type="rule"' not in out["context"]
     assert "Reflex:" not in out["context"]
@@ -140,8 +140,8 @@ def test_a_short_goal_is_shown_whole():
 
 
 def test_a_long_goal_is_cut_at_a_word_and_says_where_the_rest_is():
-    """#4036: a raw slice ended mid-word with nothing marking the cut, so a
-    reader took half a sentence for the whole goal."""
+    """A raw slice ends mid-word with nothing marking the cut, and a reader
+    takes half a sentence for the whole goal."""
     from scribe.services.plugin_context import _GOAL_CHARS, _goal_line
     goal = "make the record reach the next session\nso a solution is recalled " * 10
     line = _goal_line(goal, 2)
@@ -190,7 +190,7 @@ async def test_build_session_context_pushes_the_projects_design_system():
     assert "resolve_design_system(9)" in ctx
     assert "get_design_system_stylesheet(9)" in ctx
     # The prose pointer names the call that has the MERGED guidance, not
-    # enter_project, which carries only the summary now (#4045).
+    # enter_project, which carries only the summary.
     assert "`get_design_system(9)` → `resolved_guidance`" in ctx
 
 
@@ -230,8 +230,8 @@ async def test_build_session_context_unbound_repo_emits_bind_hint():
 
 @pytest.mark.asyncio
 async def test_a_project_id_that_does_not_resolve_is_reported_not_dropped():
-    """A `.scribe` marker names a project directly (#4085), so for the first
-    time a caller arrives holding a pointer it BELIEVES in. If the id is for
+    """A `.scribe` marker names a project directly, so a caller arrives
+    holding a pointer it BELIEVES in. If the id is for
     another instance, or names a deleted project, the session has to be told —
     it cannot infer it from an absence.
 
@@ -306,20 +306,18 @@ async def test_build_process_manifest_truncates_long_preview():
 
 @pytest.mark.asyncio
 async def test_build_session_context_caps_length():
-    """The cap still binds, and now has to be provoked rather than tripped.
+    """The cap binds, and has to be provoked rather than tripped.
 
-    This used to hand the block 200 long rule titles, because the preload made
-    overflow the easy case. Milestone 394 removed that block, so nothing this
-    function assembles on its own is big enough any more — which is a reason
-    to drive the cap directly, not a reason to drop it. The project and design
+    Nothing this function assembles on its own is ordinarily big enough to
+    overflow — which is a reason to drive the cap directly, not a reason to
+    drop it. The project and design
     blocks are still unbounded in principle, and the hook passes this text
     through verbatim.
 
     Patching the cap rather than manufacturing 9,000 characters keeps the test
     about the TRUNCATION PATH — that it cuts, and that it says it cut — which
     is the part a reader depends on. The unbound-repo hint supplies the text:
-    since milestone 410 the block carries live state only, and a bare session
-    is a one-liner.
+    the block carries live state only, and a bare session is a one-liner.
     """
     from scribe.services import plugin_context as pc
 
@@ -333,7 +331,7 @@ async def test_build_session_context_caps_length():
     )
 
 
-# --- the reuse slot (#2246) --------------------------------------------------
+# --- the reuse slot ---------------------------------------------------------
 
 _CFG = {"enabled": True, "threshold": 0.55, "top_k": 3}
 
@@ -348,7 +346,7 @@ def _asked_for_reuse(calls: list[dict]) -> bool:
 async def _autoinject(main_hits, reuse_hits, cfg=None, lesson_hits=None):
     """Run build_autoinject_hint with each semantic query stubbed by the kinds
     it asks for: the unscoped pool, the reserved reuse query, and the reserved
-    lesson query (milestone 385 step 5).
+    lesson query.
 
     ROUTED ON THE REQUESTED KINDS, not on call order, and that is the point of
     the helper. Order-keyed stubbing was fine while there was one reserved
@@ -458,7 +456,7 @@ async def test_a_process_counts_as_reuse_too():
     assert not _asked_for_reuse(calls2)
 
 
-# --- write-path widened beyond snippets (#2246, the mirror half) -------------
+# --- write-path prior art beyond snippets ------------------------------------
 
 @pytest.mark.asyncio
 async def test_write_path_semantic_arm_asks_for_experience_not_just_snippets():
@@ -517,7 +515,7 @@ async def test_write_path_labels_a_non_snippet_hit_with_its_kind():
         )
 
     ctx = out["context"]
-    # The issue says what it is — and, since #4154, where it stands: a piece of
+    # The issue says what it is — and where it stands: a piece of
     # prior art offered as "already tried" reads differently when it is still open.
     assert "· issue (todo)]" in ctx
     assert '[similar 0.72] "debounce helper"' in ctx   # the snippet does not
@@ -525,19 +523,18 @@ async def test_write_path_labels_a_non_snippet_hit_with_its_kind():
     assert "get_task(id)" in ctx and "get_snippet(id)" in ctx
 
 
-# ── The config stand-in cannot fall behind the real one (#4214) ───────────
+# ── The config stand-in cannot fall behind the real one ───────────────────
 
 @pytest.mark.asyncio
 async def test_the_config_stand_in_carries_every_key_the_real_one_does():
-    """THE GUARD `writepath_cfg`'s DOCSTRING ALREADY CLAIMED AND DID NOT HAVE.
+    """THE GUARD `writepath_cfg`'s DOCSTRING CLAIMS.
 
     Three arms read their numbers out of that dict inside a fail-open
     `except`, so a missing key does not raise where anyone can see it — the
     arm silently becomes a no-op, which is indistinguishable from the arm
     working and finding nothing. The helper derives its SURFACE keys from the
-    registry to prevent exactly that, and then #4214 added a key that is
-    deliberately not a surface: the whole derivation missed it, ten tests went
-    red at once, and the diagnosis cost a CI round.
+    registry to prevent exactly that, and a key that is deliberately not a
+    surface slips past the derivation unless the key sets are compared.
 
     Asserting the KEY SETS match, not the values: the stand-in exists to let a
     test set different numbers.
@@ -559,7 +556,7 @@ async def test_the_config_stand_in_carries_every_key_the_real_one_does():
     )
 
 
-# ─── the passage that matched travels onto the menu (#4243, #4250) ───────────
+# ─── the passage that matched travels onto the menu ──────────────────────────
 
 
 @pytest.mark.asyncio