test(retrieval-gate): three fixtures make M06, M07 and M10 decide a delivery — row 7 14 of 14

Row 7 left three mutants standing after v1.1 (11 of 14, bar 13): the passage
signal reading no body, the field signal weighing no title and no path, and a
flattened fusion (bm25.RRF_K = 10 000). Each switches off a mechanism the
default ranking runs, and each moved 0 ranks, because every synthetic concept
was short and opened with its own title -- none of the three ever decided a
delivery here.

Three bundles, one per mechanism, and one pinned set (set-mechanisms.json):

- PASSAGE: a long concept answered in one window of its body, against ten
  short concepts whose titles carry the question's words. Rank 1; with no
  body windows it falls out of k (class b).
- PATH: a concept named by its path alone, against ten decoys denser in the
  body. Rank 4 at k = 6; with no title/path weight it falls out of k.
- FUSION: gold 1st in the passage signal and 21st in the field signal, one
  decoy 10th and 11th (rank sum 19 < 20). At RRF_K = 60 the gold leads, and
  it keeps the lead through K = 180 (measured in steps of 10); flattened, the
  decoy wins k = 1.

Chose separate fixtures over one combined one because each fixture's comment
can then name the single mechanism it pins. Verified per question against all
14 mutants: no previously felled mutant is lost. src/ is untouched, MUTANT_BAR
and the roster are unchanged, the corpus pin moved with the corpus.

Gate: rows 1 and 6 go 10/10 -> 13/13, row 7 11/14 -> 14/14 GREEN, rows 2/3/4
unchanged, GATE RED: rows 5, 8. Suite: 2444 passed, 1 skipped (+3), measured
with FORCE_COLOR unset -- with FORCE_COLOR=3 in the environment Python 3.14
colours argparse help and test_each_arm_flag_carries_its_attribution fails,
independently of this change.

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

CLAUDE.md

@@ -1318,15 +1318,24 @@ and fixtures, never code.
   what a bundle looks like, this asks whether the payload for a question
   carries the fasit. **Written RED, no capability**: eight rows, exit 0 only
   when all are green, 1 otherwise, 2 on wrong input, `--json`. Rows 1-4, 6, 7
-  run against a synthetic corpus this repo GENERATES and six sets it ships
+  run against a synthetic corpus this repo GENERATES and seven sets it ships
   pinned by sha256 -- no network, no private corpus, no clock; a set whose
   bytes moved is exit 2, never a quiet continuation, because **a gold set is
   an INPUT and never a constant here** (`okf_consume_measure.py`'s rule, and
   this repo is public). **THE CORPUS IS PINNED THE SAME WAY** since
   2026-09-19 (`SPECS_SHA256`). Today (measured on the default run
-  2026-09-21, v1.1 K): **1 (10/10) - 2 (7/7) - 3 (5/5) - 4 (6/6) - 5 (0/1) -
+  2026-09-22): **1 (13/13) - 2 (7/7) - 3 (5/5) - 4 (6/6) - 5 (0/1) -
-  6 (10/10) - 7 (11/14) - 8 (0 of 1 set, NOT RUN without `--real`)**,
+  6 (13/13) - 7 (14/14) - 8 (0 of 1 set, NOT RUN without `--real`)**,
-  `GATE RED: rows 5, 7, 8`.
+  `GATE RED: rows 5, 8`. **Row 7 fells 14 of 14 since 2026-09-22**: the three
+  that survived v1.1 (M06 passage body, M07 title/path weight, M10
+  `bm25.RRF_K`) each got a fixture that makes its mechanism decide a delivery
+  (`PASSAGE`, `PATH`, `FUSION`, set `set-mechanisms.json`; the fusion one keeps
+  its lead through K = 180 and loses it at 190), with `src/` untouched. **Row
+  8's judge predates v1.1's passage delivery**: it requires a delivered text to
+  be the whole concept's bytes, so an excerpt `as_passage` cut is class (e)
+  even when it carries the citation -- the dominant miss class when row 8 is
+  run on the real set. Not changed here (a closing round on rows 7 and 8
+  measured it and left it for its own order).
   **THE K2 TEST TRACK IS RETIRED (operator 2026-09-21, v1.1 K)**: material
   tied to the operator's employer is not re-measured and not frozen, and
   public tests and gates run on invented material. Row 9 (K2) and the `r761`
@@ -1335,8 +1344,8 @@ and fixtures, never code.
   the R761/N101/N200 deliveries; `okf_accounting_gate.py` has no default real
   corpus. The synthetic corpus was re-measured for BM25 (`MISS`, `LOOKUP`,
   `QUOTA`), so rows 2 and 3 are green through their own fixtures again, and
-  row 7's mutants patch `bm25` where the default runs there; three survive
+  row 7's mutants patch `bm25` where the default runs there; the three that
-  (passage body, field title weight, `bm25.RRF_K`) with 0 ranks moved. What
+  survived with 0 ranks moved are felled since 2026-09-22 (above). What
   the text below says about rows 8/9, K2 and the three sets is history.
   **FOUR OF EIGHT CHEATING ATTACKS WENT THROUGH IT AND ARE CLOSED
   (2026-09-19).** PM's checkpoint on `2c8296b` found rows 3, 5, 7 and 8 could

README.md

@@ -84,13 +84,13 @@ here was measured; none of it is a plan.
   `--no-assets` takes the image path out entirely.
 - **Three of this repository's own gates are RED, and each red row is a stated
   finding rather than a bug to be surprised by.** The retrieval gate is red on
-  rows 5, 7 and 8, the MCP gate on row 2, and the content accounting's judge
+  rows 5 and 8, the MCP gate on row 2, and the content accounting's judge
   on rows 2, 3 and 6. For a user that means: no ranking change has yet been
   registered against a held-out set (row 5), the real-corpus row is NOT RUN
-  without its private sets and so is red rather than green by omission
+  without its private set and so is red rather than green by omission
-  (row 8), three mechanical mutants of the BM25 ranking survive with 0 ranks
+  (row 8) -- and when it IS run, its judge still requires a delivered excerpt
-  moved — the passage body, the title field weight and the fusion constant —
+  to be the whole concept's bytes, so an excerpt v1.1 cuts to its answering
-  so the gate cannot yet tell those parts from their absence (row 7), MCP anchors and concept ids are different
+  passage counts as a miss even where it carries the citation. MCP anchors and concept ids are different
   vocabularies so `okf_fetch` cannot be addressed with a set's anchor (row 2),
   and the accounting still reports real losses on the reference corpus (rows 2,
   3, 6). The rows and their numbers are under [Judge the
@@ -1196,18 +1196,18 @@ set names a consumer's documents and this repository is public. **The corpus
 is pinned the same way** (`SPECS_SHA256`): every row counts against those
 documents, so moving them without moving the pin is exit 2.
 
-**It is RED today, on rows 5, 7 and 8**, and each of those is a
+**It is RED today, on rows 5 and 8**, and each of those is a
 finding rather than a defect in the gate:
 
 | row | what it asks | today |
 |---|---|---|
-| 1 | hit@payload, one fasit entry = one unit | 10 of 10 |
+| 1 | hit@payload, one fasit entry = one unit | 13 of 13 |
 | 2 | every miss carries exactly one class, each forced by its own fixture | 7 of 7 |
 | 3 | the `rule` the payload prints for a withheld fasit is the true one | 5 of 5 |
 | 4 | an uncovered question comes back marked, a covered one does not | 6 of 6 |
 | 5 | a hold-out set, frozen and with its threshold written first | 0 of 1 |
-| 6 | every delivery confirmed against the bundle's own bytes | 10 of 10 |
+| 6 | every delivery confirmed against the bundle's own bytes | 13 of 13 |
-| 7 | mechanical mutants of the ranking and the cut, felled | 11 of 14 |
+| 7 | mechanical mutants of the ranking and the cut, felled | 14 of 14 |
 | 8 | the real set, from path + sha256 | 0 of 1 set, NOT RUN without `--real` |
 
 **The public rows run on invented material only** (operator decision
@@ -1230,13 +1230,18 @@ delivered excerpt answers — facts, no verdict, and the one bar is the gate's
 own `UNANSWERED_BAR = 2/3` — 3 of 6 to 6 of 6.
 
 Row 7's mutants patch the code the DEFAULT ranking runs (BM25 since v1.1),
-and it reports three survivors with what they moved rather than with a shrug:
+and it fells all 14. Until 2026-09-22 three survived with **0 ranks and 0
-the passage signal reading no body, the field signal weighing no title and no
+deliveries** moved -- the passage signal reading no body, the field signal
-path, and a flattened fusion (`bm25.RRF_K`) each moved **0 ranks and 0
+weighing no title and no path, and a flattened fusion (`bm25.RRF_K`) -- because
-deliveries** on these fixtures. Each has a mechanism: the field signal still
+every synthetic concept was short and opened with its own title, so none of the
-reads every body, every synthetic body opens with its own title as a heading,
+three ever decided a delivery. Three fixtures now make each one decide one
-and over two signals `K` only reorders a concept whose two ranks lie far apart,
+(`set-mechanisms.json`): a long concept answered in one window of its body
-which no fixture holds.
+against short concepts whose titles carry the question's words; a concept named
+by its path alone against decoys denser in the body; and a concept first in one
+signal and 21st in the other against a decoy 10th and 11th, which a flattened
+fusion ranks first because only the rank sum then counts. Each fixture is
+delivered at the shipped defaults and falls out of `k` with its own mechanism
+switched off; `src/` did not change.
 
 Row 8 is never green by leaving something out: it requires every named set and
 is NOT RUN until it has them — one set of three used to read `6 of 6 GREEN`.

tests/fixtures/retrieval/set-mechanisms.json

@@ -0,0 +1,28 @@
+{
+  "set_id": "synthetic-mechanisms",
+  "bundle": "passage",
+  "note": "Three questions, one per mechanism the default BM25 ranking runs and no earlier fixture made decide a delivery: the passage signal's body windows (bundle `passage`), the field signal's title and path weight (bundle `path`), and the rank-fusion constant (bundle `fusion`). Each is delivered at the shipped defaults and falls out of k when its own mechanism is switched off, so row 1 is what fells M06, M07 and M10.",
+  "questions": [
+    {
+      "id": "PA1",
+      "question": "Hvem kontrollerer varmekablene i taket?",
+      "bundle": "passage",
+      "fasit": [{"by": "concept", "value": "aarbok/kapittel-tre", "quote": "kontrolleres av vaktmesteren"}]
+    },
+    {
+      "id": "PT1",
+      "question": "Hva gjelder for vester ved kanopadling?",
+      "bundle": "path",
+      "k": 6,
+      "fasit": [{"by": "concept", "value": "kanopadling/regel", "quote": "brukes paa vannet"}]
+    },
+    {
+      "id": "FU1",
+      "question": "Hva gjelder for isbading?",
+      "bundle": "fusion",
+      "k": 1,
+      "fasit": [{"by": "concept", "value": "badebok/kapittel", "quote": "isbading om morgenen"}]
+    }
+  ],
+  "controls": []
+}

tests/test_retrieval_gate.py

@@ -632,14 +632,15 @@ def test_the_gate_is_red_today_and_says_which_rows(tmp_path: Path) -> None:
     by_number = {row.number: row for row in rows}
     assert sorted(by_number) == [1, 2, 3, 4, 5, 6, 7, 8]
     # Rows 2 and 3 are green again since the synthetic corpus was re-measured
-    # for BM25 (2026-09-21). Row 7 is red on three survivors, each printed with
+    # for BM25 (2026-09-21). Row 7 fells all 14 since 2026-09-22, when the three
-    # what it moved.
+    # v1.1 survivors each got a fixture that makes their mechanism decide a
-    assert [row.number for row in rows if row.fails] == [5, 7, 8]
+    # delivery (`set-mechanisms.json`, three more row-1 units).
-    assert (by_number[1].k, by_number[1].m) == (10, 10)
+    assert [row.number for row in rows if row.fails] == [5, 8]
+    assert (by_number[1].k, by_number[1].m) == (13, 13)
     assert (by_number[2].k, by_number[2].m) == (7, 7)
     assert (by_number[3].k, by_number[3].m) == (5, 5)
-    assert (by_number[6].k, by_number[6].m) == (10, 10)
+    assert (by_number[6].k, by_number[6].m) == (13, 13)
-    assert (by_number[7].k, by_number[7].m) == (11, 14)
+    assert (by_number[7].k, by_number[7].m) == (14, 14)
 
 
 def test_the_same_tree_measures_the_same_twice(tmp_path: Path) -> None:
@@ -655,7 +656,7 @@ def test_the_command_exits_one_and_prints_every_row(
     printed = capsys.readouterr().out
     for number in range(1, 9):
         assert f"\n{number} " in f"\n{printed}"
-    assert "GATE RED: rows 5, 7, 8" in printed
+    assert "GATE RED: rows 5, 8" in printed
 
 
 def test_the_json_form_carries_the_same_rows(capsys: pytest.CaptureFixture[str]) -> None:

tools/okf_retrieval_gate.py

@@ -434,6 +434,158 @@ BUDGET = BundleSpec(
     ),
 )
 
+# --- three fixtures, one per mechanism the default ranking runs ---------------
+#
+# Until 2026-09-22 row 7 left three mutants standing (M06, M07, M10): every
+# synthetic concept was short and opened with its own title, so the passage
+# signal, the title/path weight and the fusion constant never DECIDED a
+# delivery here, and switching any of them off moved 0 ranks. Each bundle below
+# is built so that exactly one of them does. None of them is a tuning of the
+# ranker: the corpus is pinned (`SPECS_SHA256`) and `src/` is untouched.
+
+_NOTE = "Styret gjennomgaar notatet og foerer det inn i arkivet. Sekretaeren sender kopi. "
+
+#: THE PASSAGE SIGNAL. One long concept answers in ONE window of its body; ten
+#: short concepts carry the question's words in their TITLES and none in their
+#: bodies. The field signal reads ten title-weighted matches in short documents
+#: above one long body, so only the passage signal -- the best WINDOW, not the
+#: whole concept -- puts the gold first. Remove the body windows (M06) and the
+#: passage signal reads titles alone, where the gold has none of the words.
+PASSAGE = BundleSpec(
+    "retrieval-passage",
+    (
+        DocumentSpec(
+            "aarbok",
+            "aarbok.md",
+            (
+                ConceptSpec(
+                    "kapittel-tre",
+                    "Kapittel tre i aarboka",
+                    _NOTE * 15
+                    + "Varmekablene i taket kontrolleres av vaktmesteren hver oktober. "
+                    + _NOTE * 15,
+                ),
+            ),
+        ),
+        *(
+            DocumentSpec(
+                f"rundskriv-{number:02d}",
+                f"rundskriv-{number:02d}.md",
+                (
+                    ConceptSpec(
+                        f"skriv-{number:02d}",
+                        f"Varmekablene i taket, skriv {number:02d}",
+                        "Skrivet er sendt ut og arkivert.",
+                    ),
+                ),
+            )
+            for number in range(1, 11)
+        ),
+    ),
+)
+
+#: THE TITLE/PATH WEIGHT. The gold is named by its PATH alone -- the question's
+#: `kanopadling` is its directory and its source file and occurs in no body --
+#: while ten decoys carry the question's other word more densely than the gold
+#: does, one fewer time each. The path weight puts the gold first in the field
+#: signal, which lifts it into k (rank 4 at `k` = 6). Weigh no title and no path
+#: (M07) and both signals read bodies only, where the decoys outrank it and it
+#: falls out of k.
+PATH = BundleSpec(
+    "retrieval-path",
+    (
+        DocumentSpec(
+            "kanopadling",
+            "kanopadling.md",
+            (ConceptSpec("regel", "Regel om vester", "Vester brukes paa vannet."),),
+        ),
+        *(
+            DocumentSpec(
+                f"turnotat-{number:02d}",
+                f"turnotat-{number:02d}.md",
+                (
+                    ConceptSpec(
+                        f"notat-{number:02d}",
+                        f"Turnotat {number:02d}",
+                        " ".join(["Vester henger i boden."] * (11 - number))
+                        + " Notatet er arkivert.",
+                    ),
+                ),
+            )
+            for number in range(1, 11)
+        ),
+    ),
+)
+
+_FUSION_NOTE = "Styret gjennomgaar saken og sekretaeren arkiverer den. "
+
+#: THE FUSION CONSTANT. Reciprocal-rank fusion trades a concept with one very
+#: good rank against one with two middling ranks, and `RRF_K` sets the price.
+#: The gold is FIRST in the passage signal and 21st in the field signal (a long
+#: body, below ten short `isbading-*` path matches, nine longer ones and the
+#: decoy); the one decoy is 10th and 11th, a smaller rank SUM (19 against 20).
+#: A flattened fusion (M10, `RRF_K` = 10 000, where only the sum counts) puts
+#: the decoy first and `k` = 1 no longer reaches the gold. At the shipped
+#: `RRF_K` = 60 the gold leads, and measured over K in steps of 10 it keeps the
+#: lead through K = 180 and loses it at 190. The eight long log pages hold the
+#: decoy's passage rank at 10th and rank below the gold in both signals.
+FUSION = BundleSpec(
+    "retrieval-fusion",
+    (
+        DocumentSpec(
+            "badebok",
+            "badebok.md",
+            (
+                ConceptSpec(
+                    "kapittel",
+                    "Kapittel i badeboka",
+                    _FUSION_NOTE
+                    * 12
+                    + "Isbading ved brygga, isbading om morgenen, isbading med vakt, "
+                    "isbading hver dag. " + _FUSION_NOTE * 12,
+                ),
+            ),
+        ),
+        *(
+            DocumentSpec(
+                f"logg-{number:02d}",
+                f"logg-{number:02d}.md",
+                (
+                    ConceptSpec(
+                        "side",
+                        f"Loggside {number:02d}",
+                        _FUSION_NOTE * 16
+                        + "Isbading ved brygga, isbading om kvelden, isbading med vakt. "
+                        + _FUSION_NOTE * 16,
+                    ),
+                ),
+            )
+            for number in range(8)
+        ),
+        DocumentSpec(
+            "isbading-lapp-00",
+            "isbading-lapp-00.md",
+            (ConceptSpec("lapp", "Lapp 00", _FUSION_NOTE * 5 + "Isbading er tillatt."),),
+        ),
+        *(
+            DocumentSpec(
+                f"isbading-{number:02d}",
+                f"isbading-{number:02d}.md",
+                (ConceptSpec("oppslag", f"Oppslag {number:02d}", "Oppslaget er arkivert."),),
+            )
+            for number in range(10)
+        ),
+        *(
+            DocumentSpec(
+                f"isbading-arkiv-{number:02d}",
+                f"isbading-arkiv-{number:02d}.md",
+                (ConceptSpec("mappe", f"Mappe {number:02d}", _FUSION_NOTE * 10),),
+            )
+            for number in range(9)
+        ),
+    ),
+)
+
 SPECS: Mapping[str, BundleSpec] = {
     "positive": POSITIVE,
     "miss": MISS,
@@ -441,6 +593,9 @@ SPECS: Mapping[str, BundleSpec] = {
     "budget": BUDGET,
     "lookup": LOOKUP,
     "quota": QUOTA,
+    "passage": PASSAGE,
+    "path": PATH,
+    "fusion": FUSION,
 }
 
 
@@ -483,7 +638,7 @@ def specs_digest(specs: Mapping[str, BundleSpec] = SPECS) -> str:
 
 
 #: The synthetic corpus, pinned the way the sets are.
-SPECS_SHA256 = "23c447add9a58ee2e454ef5d5b92d5c3c97d441cd883d203aaf2f275dd2f68f9"
+SPECS_SHA256 = "abf24378c32b02753916c36eb502f9b27183a5d1c7e1914b40773bde393878b5"
 
 
 def synthetic_bundles(root: Path, specs: Mapping[str, BundleSpec] = SPECS) -> dict[str, Path]:
@@ -648,6 +803,7 @@ SYNTHETIC_SETS: dict[str, str] = {
     "set-signals.json": "17d83f305a10af8dd2a45b72943c1285704d23ed074ecb549c05e5fac3e137e9",
     "set-quota.json": "61fda652719d7403ddf9701d50e914c46572a4fda77dc0336838695e18c498cf",
     "set-controls.json": "c2894656326e5a69ec7063fdc280e763910d20b4cbc2c0124f639283864ce506",
+    "set-mechanisms.json": "435ce620c30c94b0d151335883583520490482be2ade6797524ae928a9f1eab7",
 }
 
 
@@ -1599,8 +1755,10 @@ class Mutant:
     expected_row: int
     patch: Callable[[], contextlib.AbstractContextManager[None]]
     #: Why this one may be invisible to a gate that judges DELIVERY. Written
-    #: for the two that survive, so a survivor is a statement about the
+    #: for a mutant that survives, so a survivor is a statement about the
-    #: mechanism and not a shrug.
+    #: mechanism and not a shrug. None does since 2026-09-22: the three that
+    #: carried a note (M06, M07, M10) each got a fixture that makes their
+    #: mechanism decide a delivery (`PASSAGE`, `PATH`, `FUSION`).
     note: str = ""
 
 
@@ -1717,23 +1875,12 @@ MUTANTS: tuple[Mutant, ...] = (
     Mutant("M04 the ranking is reversed", 1, _reverse_scores),
     Mutant("M05 the source quota is removed", 3, lambda: _wrap_cut(source_quota=None)),
     Mutant(
-        "M06 the passage signal reads no body",
+        "M06 the passage signal reads no body", 1, lambda: _patched_bm25(windows=lambda body: [])
-        1,
-        lambda: _patched_bm25(windows=lambda body: []),
-        note=(
-            "the field signal still reads every body, and no synthetic concept is "
-            "long enough for its best window to decide a delivery"
-        ),
     ),
     Mutant(
         "M07 the field signal weighs no title and no path",
         1,
         lambda: _patched_bm25(TITLE_WEIGHT=0, PATH_WEIGHT=0),
-        note=(
-            "every synthetic body opens with its own title as a heading "
-            "(`build_bundle`), so the weight only re-weights words the body "
-            "already carries"
-        ),
     ),
     Mutant("M08 every token matches every token", 4, _every_term_everything),
     Mutant("M09 no stem, no prefix: equality only", 1, _equality_only),
@@ -1741,10 +1888,6 @@ MUTANTS: tuple[Mutant, ...] = (
         "M10 the fusion is flattened (bm25.RRF_K = 10 000)",
         1,
         lambda: _patched_bm25(RRF_K=10_000),
-        note=(
-            "over two signals K reorders only a concept whose two ranks lie far "
-            "apart against one whose ranks are close, and no fixture here holds that"
-        ),
     ),
     Mutant("M11 the cut takes the LAST k", 1, _last_k),
     Mutant("M12 the delivered text is truncated to 40 characters", 6, _truncate_delivered),