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_note_usage.py

@@ -1,4 +1,4 @@
-"""Tests for the usage signal (#2085) — was a surfaced record ever pulled?
+"""Tests for the usage signal — was a surfaced record ever pulled?
 
 Covers the payload shaping and the two contracts that make this safe to leave in
 the hot path: telemetry never raises, and telemetry never blocks. Plus the thing
@@ -90,8 +90,8 @@ async def test_usage_for_notes_splits_counts_by_event():
     from datetime import datetime, timezone
 
     ts = datetime(2026, 7, 28, tzinfo=timezone.utc)
-    # Rows are (note_id, event, count, last_at, ambient) since #2477 split the
-    # readout. Ranked and ambient surfacings arrive as separate groups.
+    # Rows are (note_id, event, count, last_at, ambient): ranked and ambient
+    # surfacings arrive as separate groups.
     rows = [
         (3, "surfaced", 9, ts, False),
         (3, "surfaced", 40, ts, True),
@@ -111,7 +111,7 @@ async def test_usage_for_notes_splits_counts_by_event():
         out = await usage_for_notes([3])
     # The dead-weight reading ("surfaced often, never pulled") is only valid
     # over surfacings that were CHOICES. 40 enter_project appearances must not
-    # make a record look popular — they sit in ambient_count (#2477).
+    # make a record look popular — they sit in ambient_count.
     assert out[3]["surfaced_count"] == 9
     assert out[3]["ambient_count"] == 40
     assert out[3]["pull_count"] == 2
@@ -120,7 +120,7 @@ async def test_usage_for_notes_splits_counts_by_event():
 
 async def test_usage_for_notes_counts_what_happened_away_from_home():
     """Surfaced or opened on a project other than the record's own is the
-    evidence a record transferred (#3735). It is a SUBSET of the totals, read
+    evidence a record transferred. It is a SUBSET of the totals, read
     from the second aggregate, and it must land on the right counter."""
     from datetime import datetime, timezone
 
@@ -167,7 +167,7 @@ async def test_no_ids_short_circuits_without_a_query():
 @pytest.mark.parametrize(
     "lookups, expected_source",
     [
-        # A hit AT the exact file is the sync class (#2708); a hit from the
+        # A hit AT the exact file is the sync class; a hit from the
         # directory query is the reuse-shaped place arm. Both are un-scored,
         # and both must leave a usage trace under their own name.
         ([(1, "hit"), (2, "empty")], "write_path_sync"),
@@ -177,9 +177,8 @@ async def test_no_ids_short_circuits_without_a_query():
 )
 async def test_unscored_location_arms_are_recorded(lookups, expected_source):
     """The location arms carry no score, so they have no home in retrieval_logs
-    — they surfaced snippets while leaving no trace anywhere. That was the
-    blocker #2082 recorded against this task; this is the assertion that it's
-    closed, per class."""
+    — without a usage row they would surface snippets while leaving no trace
+    anywhere. Asserted per class."""
     from scribe.services import plugin_context
 
     here = [{"id": 42, "title": "helper", "user_id": 1, "note_type": "snippet"}]
@@ -237,15 +236,13 @@ async def test_auto_inject_records_what_survived_the_margin_gate():
 
 
 def test_every_getter_that_can_be_surfaced_also_records_a_pull():
-    """Rule #33 contract check — and the one that would have caught #2245.
+    """A contract check between the two halves of the usage pair.
 
     `surfaced` and `pulled` only mean something as a PAIR: the rate between them
-    is what #1038 and #2085 gate on. That pair is only closed if the tool which
-    OPENS a record reports it. `get_note` did, `get_snippet` did, `get_task` did
-    NOT — and auto-inject ranks kind-blind over a corpus that is overwhelmingly
-    tasks and issues, so the gap sat exactly where the volume is: every surfaced
-    task counted as never-pulled, dragging measured pull-through toward zero for
-    the menu's own dominant kind.
+    is what pull-through is read from. That pair is only closed if every tool
+    which OPENS a record reports it — and auto-inject ranks kind-blind over a
+    corpus that is mostly tasks and issues, so one getter that does not report
+    counts the menu's dominant kind as never-pulled.
 
     Asserted by source inspection rather than by calling the tools, because the
     failure is a MISSING call — which no behavioural test of the tool's return
@@ -272,12 +269,11 @@ def test_every_getter_that_can_be_surfaced_also_records_a_pull():
 
 # --- persistence (integration) --------------------------------------------
 # Everything above mocks _schedule or the session — deliberately, for the hot
-# path. But that left the two functions that actually touch the database
-# (_insert_events and usage_for_notes' real SQL) running against real Postgres
-# nowhere, which is how the deployed instance reported zero for every counter
-# while surfacing demonstrably fired (#2663): all-green mocked units over a
-# dead real path, the #2109 shape. These two run in the CI integration lane
-# and split the chain so a failure names its half.
+# path. Without these, the two functions that actually touch the database
+# (_insert_events and usage_for_notes' real SQL) would run against real
+# Postgres nowhere — all-green mocked units over a dead real path. These two
+# run in the CI integration lane and split the chain so a failure names its
+# half.
 
 
 async def _purge(note_id: int) -> None:
@@ -309,7 +305,7 @@ async def test_insert_and_readout_roundtrip_on_real_postgres(_dispose_engine):
              "source": "mcp_get_snippet"},
         ])
         out = await usage_for_notes([nid])
-        # write_path_place is a ranked choice; enter_project is ambient (#2477).
+        # write_path_place is a ranked choice; enter_project is ambient.
         assert out[nid]["surfaced_count"] == 1
         assert out[nid]["ambient_count"] == 1
         assert out[nid]["pull_count"] == 1