docs(k3): round 19, a document's own identity, per-run frontmatter, and a description from the source

The report for K3-19, measured from a frozen export of 77e7cab: R761 from the
base 56b00e7 against 77e7cab -- directory `14ce59dc-...` -> `r761-prosesskoden`,
2 761 concepts and 710 shells unchanged, 110 = 110, 1 807 descriptions, the
flagged edition and address on 2 761 of 2 761, hit@1/8/50 over S1-S6 6/6 at
both k, `okf check` 4 of 4 with 0 findings, and --ingested-at alone
confirmed on 2 761 of 2 761.

Reported first rather than repaired: the known-positive falls from rank 1 to
not delivered at the default k (13 at k = 50), decomposed to the directory
name alone; and the order's own `sources` value is refused by PyYAML on every
concept while `okf check` accepts it.

CHANGELOG under [Unreleased], the README and CLAUDE.md paragraphs carry the
final numbers, and the README test count moves to 1659 collected.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,65 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- **A NISO-STS document's own identity names its directory and titles its
+  `sources` entry (K3-19).** `okf build` put every concept of an STS delivery
+  under a directory named for the delivery file -- measured, a UUID occurring
+  0 times in the document -- while the document's one `<std-ident>` carried a
+  `<doc-number>`. `extract.declared_identity` reads exactly one `<std-ident>`
+  (`<doc-number>`, `<year>`) and exactly one `<title-wrap>`; a value stated
+  more than once is not read. The directory is the `<doc-number>` through the
+  id grammar, replacing only the file's stem, and `sources[0].title` is
+  `<doc-number>` + `<year>`, then the `<title-wrap>` title, then the file name
+  -- the first that can be written into the flow mapping verbatim (the
+  measured `<full>` carries commas, so it never is). A declared name two
+  documents in one run claim is used by neither, and stderr says so.
+  - **Consumer cost: a re-run, and an STS document's concept ids move**
+    (`<uuid>/...` -> `<doc-number>/...`). Every other file type is untouched:
+    the five-document folder rebuilds identical except the `log.md` line that
+    records the venv's converter path.
+  - **Measured side effect on ranking, reported rather than repaired:** hit@1
+    / 8 / 50 over S1-S6 stays 6/6 at both `k`, but the known-positive falls
+    from rank 1 to not delivered at the default `k` (13 at `k` = 50).
+    `consume`'s first signal reads a concept id's segments, and on a
+    one-document bundle every id now carries the document's own name; renaming
+    only the directory back restores rank 1. `--rarity-weight` delivers it at
+    rank 4 with S1-S6 unmoved, and stays off.
+
+### Added
+
+- **`okf build --frontmatter KEY=VALUE`**, repeatable, stamps a key on every
+  concept of a run -- for what an operator knows and a document does not say,
+  such as an edition or a publisher's address. SPEC SS 4.1 "Extensions" lets
+  a producer add any key; SS 11 forbids a consumer to reject one. Split on the
+  FIRST `=`, and the value is written verbatim on ONE line, because this
+  package's readers are line-oriented and blind to a block-form `sources`.
+  Precedence: a stated value beats what the document declares, which beats the
+  file name. A run may add any key and REPLACE only `sources` and
+  `description`; every key the door writes itself -- including Door A's
+  `ingest_manifest`, which would make that door claim the file -- is refused
+  before a proposal is written (`run_frontmatter_invalid`), as is a value that
+  would not read back as stated. Reachable as `build(frontmatter=...)` and as a
+  keyword-only `concept_frontmatter_values` on `measure`, `process_inbox` and
+  `render_inbox_concept`. Without the flag nothing moves. **Note:** a
+  `sources` value carrying a URL or `X:Y` in the flow mapping passes `okf
+  check` and is refused by PyYAML's `safe_load` -- measured on 2 761 of 2 761
+  concepts with such a value -- and it is written verbatim as stated.
+- **`description` for an STS section, from its own first spec point.** The
+  first `<p>` of the first direct-child `<sec sec-type="spec">`, whole,
+  carried by the plan entry, screened by the gate, and written only where a
+  YAML reader reads it verbatim (`inbox._yaml_plain`; over 2 024 measured
+  values the rule and PyYAML agree on every one). The spec sets no length, so
+  the one-paragraph limit is ours. On the measured document: 2 026 of 2 761
+  titled sections carry a spec point, 1 807 descriptions are written (2 points
+  have no `<p>`, 217 carry `": "`), none is invented, and none is derived from
+  a title.
+
+`--ingested-at` alone was confirmed to stamp every concept, on the segmented
+route too, and to date `log.md`: 2 761 of 2 761. Report:
+[`docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md`](docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md).
+
 ## [0.8.2] — 2026-09-11
 
 ### Added

CLAUDE.md

@@ -132,9 +132,19 @@ one boundary rule:
   R761's `<full>` carries a COMMA, a flow terminator, so it is never written
   and never cleaned up. A titled section's `description` is its own FIRST
   spec point (first `<p>` of the first DIRECT-child `sec-type="spec"`, whole),
-  carried by the plan entry and screened by the gate: 2 026 of 2 761 on R761,
+  carried by the plan entry, screened by the gate, and written only where a
-  none invented for the rest. SS 4.1 sets no length, so the one-paragraph
+  YAML reader reads it verbatim (`inbox._yaml_plain`): 2 026 of 2 761 titled
-  limit is ours. The registries are COUPLED: a row in
+  sections on R761 carry a point, **1 807** are written (2 have no `<p>`, 217
+  carry `: ` and PyYAML refused exactly those frontmatters), none invented.
+  SS 4.1 sets no length, so the one-paragraph limit is ours. **The directory
+  name reaches the RANKING:** `consume`'s signal 1 reads the concept id's
+  segments, so on a one-document bundle every concept now carries the
+  document's own name, and a question naming the document matches all of
+  them -- measured, the known-positive went rank 1 -> not delivered at the
+  default `k` (13 at k=50) with S1-S6 unmoved, and renaming only the
+  directory back restores rank 1. Operator question, not a patch. Report:
+  `docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md`. The
+  registries are COUPLED: a row in
   `_CORE_EXTRACTORS` and not in `segmentation._STDLIB_EXTRACTOR_IDS` refuses
   every proposal for the type, two layers away from the extractor.
   `pdf`/`docx`/`xlsx` only via

README.md

@@ -643,7 +643,10 @@ bundle:
    declared name is not used and the file name stays. Each titled section's
    `description` is its own first spec point — the first `<p>` of its first
    direct-child `<sec sec-type="spec">`, whole — and a section with none gets
-   no `description` at all; nothing is derived from the title.
+   no `description` at all; nothing is derived from the title. A point a YAML
+   reader could not read verbatim (a `: ` inside it) is left out rather than
+   quoted or cleaned up. Measurements:
+   [`docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md`](docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md).
    The drop directory is walked **recursively**, in sorted relative-path order:
    a file at any depth is ingested and records its path relative to the inbox
    root as its `source_file`, while dot-directories and a bundle directory
@@ -855,15 +858,16 @@ From a checkout, the test suite runs with:
 .venv/bin/python -m pytest
 ```
 
-The suite is the verification surface for everything above: **1603 tests
+The suite is the verification surface for everything above: **1659 tests
-collected, 1602 passed and 1 skipped**, run on 2026-09-11 with the `[extract]`
+collected, 1658 passed and 1 skipped**, run on 2026-09-11 with the `[extract]`
 extra installed. Both numbers are given because they are two measurements: the
-figure published before this round was the PASSED count, and `pytest
+figure published before the `v0.8.2` release was the PASSED count, and `pytest
 --collect-only -q` reported one more.
 (The figure stood at 596 until 2026-09-09 — measured 2026-08-21 and never
 updated as the suite grew — at 1515 until the `v0.8.0` release, at 1575
-through it, at 1582 through the `v0.8.1` release, and at 1602 through the
+through it, at 1582 through the `v0.8.1` release, at 1602 through the
-`v0.8.2` release: a count is a measurement with a date on it.)
+`v0.8.2` release, and at 1658 after K3-19: a count is a measurement with a
+date on it.)
 Without the extra the same suite skips the tests covering the parser path;
 that split was last counted on 2026-08-21 as 589 passed and 7 skipped and has
 **not** been re-measured since. The tests holding the fail-fast rejection for

docs/2026-09-11-k3-runde19-dokumentidentitet-og-frontmatter.md

@@ -0,0 +1,275 @@
+# K3 round 19: a document's own identity, per-run frontmatter, and a description from the source
+
+**Date:** 2026-09-11 · **Base:** `56b00e7` · **Commits:** `be169ee` (red),
+`ee8d5b5`, `72617ac` (red), `912b850`, `0dbc331` (red), `de7849e`, `31ffc2c`
+(red), `77e7cab` · **Measured from:** a frozen `git archive` export of
+`77e7cab`, never the working tree and never the `okf` on PATH.
+
+A NISO-STS document built with `okf build` landed every concept under a
+directory named for its delivery file, and every `sources` entry named that
+file twice. A consumer's own build of the same kind of document carried an
+edition key, a publisher's address and a `description`, and `okf build` could
+carry none of them. This round closes those four points in general code: no
+name of a document, a publisher or a corpus appears in `src/`.
+
+## 0. Where the measurement differs from the order, first
+
+- **HEAD was `56b00e7`, not the `e15de71` the order recorded.** The R4 release
+  landed after the order was written. No commit since `e15de71` touched
+  `inbox.py`, `propose.py`, `cli.py`, `extract.py`, `profiles.py` or
+  `tests/test_xml_sts.py` (empty `git log`, rc 0), and `uv.lock` was clean, so
+  nothing had to be checked out.
+- **The known-positive falls, and the directory name is the whole cause.**
+  S1–S6 hold at 6/6 · 6/6 · 6/6 at both `k`, as the order required. The
+  known-positive (KP) row went from **rank 1 at both `k`** on the base to **not
+  delivered at the default `k` and rank 13 at `k` = 50**. Decomposed in § 7:
+  the same bundle with only the directory renamed back to the file name puts KP
+  at rank 1 again, and the same bundle with every `description` removed does
+  not move it.
+- **The order's own `--frontmatter 'sources=...'` value is not YAML that
+  PyYAML reads.** With it, **2 761 of 2 761** concepts' frontmatter fail
+  `yaml.safe_load` (a `:` inside a flow-mapping plain scalar, in the URL and in
+  `R761:2025`). The consumer bundle the order modelled it on has the same
+  property: **446 of 446** of its `sources` lines fail the same way. `okf
+  check` accepts both, with 0 findings. The flag writes the operator's value
+  verbatim, as ordered; this is reported, not repaired.
+- **1 807 descriptions are written, not 2 026.** 2 026 titled sections carry a
+  direct-child spec point. 2 of those points have no `<p>`, and **217 carry
+  `": "`**, which a YAML reader refuses in `description: a: b`. The first build
+  wrote them and made 217 frontmatters unreadable to PyYAML. That was repaired
+  before delivery (`31ffc2c` red, `77e7cab`); § 5.
+- **The 43-document reference corpus was not rebuilt.** It holds **0 `.xml` of
+  86 files** (known-positive in the same query: 66 `.pdf`), and every change
+  here is reached only through `.xml` or through a flag the build did not
+  receive. The pinned bundle's test runs as before (§ 8).
+
+## 1. The spec, and what it does not say
+
+Checked against the canonical text first (`docs/okf-nokkelinventar.md § 0.1`):
+`curl` of upstream `okf/SPEC.md` exit 0, 37 748 bytes, `diff` against the local
+copy **0 lines**, 1 006 lines, "Version 0.2".
+
+- § 4.1, l. 205: "**Extensions:** Producers MAY include any additional keys.
+  Consumers SHOULD preserve unknown keys when round-tripping and MUST NOT
+  reject documents with unrecognized fields."
+- § 11, l. 760: "Unknown additional frontmatter keys." among what a consumer
+  MUST NOT reject a bundle for.
+- § 4.1 on `description`: "A single sentence summarizing the concept." **No
+  length limit exists** in § 4.1, § 8 or § 11 (`grep -n description` over the
+  spec is the denominator: 17 lines, none a limit). The one-paragraph limit in
+  § 5 is this package's own.
+
+Conformance is the floor and never the proof: every number below that says
+"`okf check` 0 findings" is a statement about the contract checker, and § 0
+already has one bundle it accepts that a YAML parser does not.
+
+## 2. (a) The document's identity names its directory and titles its address
+
+`extract.declared_identity(name, data)` reads what a NISO-STS document states
+about itself: exactly one `<std-ident>` (`<doc-number>`, `<year>`) and exactly
+one `<title-wrap>` (`<full>`, else `<main>`). It is `None` for every other file
+type, for XML that is not STS, for an unparseable file and for a document
+stating neither. A value stated more than once is not read: an adopted
+standard carries one `<std-ident>` per issuing body, and taking the first is a
+guess.
+
+Measured on R761: **1** `<std-ident>`, **1** `<doc-number>` (`R761
+Prosesskoden`), **1** `<title-wrap>`, `<year>` 2025. The delivery file's stem
+occurs **0 times** in the document. `<doc-type>` reads `Innledning`, the name
+of a chapter, and nothing uses it.
+
+**The directory.** `okf build` replaces the file's stem with the
+`<doc-number>` reduced to the id grammar and keeps the folders above it:
+`r761-prosesskoden/`, where the base wrote the UUID.
+
+**A declared name two documents claim is used by neither.** If a second
+document in the run declares the same name, or its file name reduces to it,
+both keep their file name, and stderr says which documents and which name. The
+collision gate Door B already has would refuse both with "rename one", and a
+name read from inside a document is not one a rename can change. Tested with
+two documents sharing a `<doc-number>` and with a document whose file name
+holds the declared name.
+
+**The `sources` title.** The candidates are `<doc-number>` + `<year>`, then the
+`<title-wrap>` title, then the file name. The first that passes the gate and
+can be written into the flow mapping verbatim wins. The order left the choice
+between the first two to measurement:
+
+| `sources[0].title` | hit@k S1–S6, both `k` | KP (default / 50) | bytes spent over 8 questions (default / 50) | excerpts delivered at `k` = 50 |
+|---|---|---|---|---|
+| `R761 Prosesskoden 2025` (shipped) | 1,1,1,1,1,1 | – / 13 | 278 693 / 853 803 | 348 |
+| `<full>` with its commas removed | 1,1,1,1,1,1 | – / 13 | 282 289 / 854 200 | 346 |
+
+**They rank identically.** `consume` passes `sources` through to the excerpt
+and ranks on neither. The full title costs 3 596 bytes more at the default `k`
+and two excerpts at `k` = 50. The order's rule for a tie is the shorter one.
+The deciding fact is structural anyway: R761's `<full>` carries **commas**,
+which end a flow mapping, and the guard refuses the quoted scalar that could
+carry them. It cannot be written verbatim, so the comma-free row exists only
+in this measurement. A title is never cleaned up, because a title with its
+commas removed is not the document's title.
+
+`resource` stays the inbox-relative file. The address says where the bytes
+are; the title says what they call themselves.
+
+## 3. (b) `--frontmatter KEY=VALUE`
+
+One form, repeatable, and a `--frontmatter-file` was not built. The consumer
+bundle measured carries eight keys of its own, and eight flags are still
+readable. A file would be a second parser for the same mapping.
+
+- **Split on the FIRST `=`, and only there.** A publisher's address carries
+  `?languageCode=nb`.
+- **Written verbatim on ONE line.** This package's readers are line-oriented,
+  and a block-form `sources` is invisible to `parse_frontmatter` (measured in
+  `vegnormal-okf` 2026-09-08 and cited by the order). The flow form is the only
+  one that survives our own readers. The test reads a stated `sources` back
+  through both `parse_frontmatter` and `consume.read_sources`.
+- **Precedence: flag > what the document declares > file name.** A run may
+  ADD any key and REPLACE only `sources` and `description`, the two keys with a
+  layer below the flag. Tested on both layers. A stated `sources` gives exactly
+  one `sources` line, on the STS document and on a markdown one.
+- **Refused before a proposal is written** (`run_frontmatter_invalid`): every
+  key the door writes itself (`inbox._door_keys`). That covers the hash, the
+  offsets, the locators, `type`, `ingested_at`, the bundle id, the ownership
+  stamp, the derived facets and `derived` itself. It also covers Door A's
+  `ingest_manifest`, which would make that door claim a Door B file. Also
+  refused: a key outside `[A-Za-z_][A-Za-z0-9_-]*`, and a value that is empty,
+  spans lines or has surrounding whitespace, since `parse_frontmatter` strips
+  it. A key given twice is refused rather than resolved.
+- **Nothing moves without it.** A test holds the flagged tree to the plain
+  one minus exactly the stated line. `okf project` does not take the flag,
+  because it owns no flag that moves a bundle's bytes.
+
+## 4. (c) and the YAML repair
+
+The NISO-STS reader records, per titled `<sec>`, the **first `<p>` of the
+first direct-child `<sec sec-type="spec">`**, whole. The plan entry carries it
+beside `title`, because a plan is the record a rebuild replays. The door writes
+it after the gate has seen it: it is document text persisted outside the body
+the gate screens, so it is kept only on the non-blocking floor and only as the
+sanitized text. A section with no such point gets no key. Nothing is derived
+from the title.
+
+Measured on R761: **2 026 of 2 761** titled sections carry a direct-child spec
+point. 264 of those points hold more than one `<p>` and 2 hold none. The first
+`<p>` runs **17 / 109 / 273 / 521 / 942** characters at min / median / p90 /
+p99 / max. A character cap was not chosen, because a cut inside a paragraph
+writes a sentence the source never wrote.
+
+**The repair.** The first build from `de7849e` wrote 2 024 descriptions, and
+PyYAML's `safe_load` refused **218 of 2 761** frontmatters: 217 on
+`description`, all carrying `": "`, and 1 on a `title` the base already had.
+`inbox._yaml_plain` is now checked where the value is written. It refuses a
+leading YAML indicator, `": "`, `" #"`, a trailing `:`, a tab or a line break.
+Over the 2 024 measured values the rule and PyYAML agree on **every one**: 217
+refused, 0 refused that PyYAML reads, 0 kept that it does not. Omitted rather
+than quoted, because a quoted value comes back from our line readers with its
+quotes. After: **1 807** descriptions, and **1 of 2 761** frontmatters refused
+by PyYAML, which is the base's own `title`.
+
+That `title` class is older than this round and is not touched here: **41 of
+436** concepts on the pinned 43-document bundle fail `safe_load` on `title`.
+
+## 5. (d) `--ingested-at` alone: confirmed, nothing built
+
+Built with `--ingested-at 2026-09-08T12:00:00Z` and no `--proposed-at`:
+**2 761 of 2 761** concepts carry that stamp, on the segmented route where the
+door reads the plan's `proposed_at`, and `log.md` is dated `## 2026-09-08`. The
+base carried the same, so the `1970-01-01T00:00:00Z` in the consumer's bundle
+came from a build that passed no stamp. The flag works as specified.
+`tests/test_cli_build.py::test_ingested_at_alone_stamps_every_concept_the_same`
+already held it.
+
+## 6. V1 FERDIG — R761, base `56b00e7` against `77e7cab`
+
+Built with `--bundle-id r761-prosesskoden-2025 --okf-version 0.2 --ingested-at
+2026-09-08T12:00:00Z`. The flagged build adds `--frontmatter utgave=R761:2025`
+and a `sources` value addressing the publisher's viewer.
+
+| row | base | after | denominator |
+|---|---|---|---|
+| document directory | `14ce59dc-…` (the file's UUID) | **`r761-prosesskoden`** | 1 |
+| concepts | 2 761 | **2 761** | — |
+| conservation | 110 = 110 | **110 = 110** | N = 110 (109 images `extractor_unknown`, expected) |
+| shells (body with no non-heading line) | 710 | **710** | 2 761 |
+| `sources[0].title`, no flag | the file name | **`R761 Prosesskoden 2025`** | 2 761 |
+| `sources`, flagged | — | the stated value, **one line** | 2 761 |
+| `utgave`, flagged | — | **2 761** | 2 761 |
+| `description` | 0 | **1 807** | 2 026 with a spec point |
+| `ingested_at` = the stamp | 2 761 | **2 761** | 2 761 |
+| frontmatter refused by PyYAML, no flag | 1 (`title`) | **1** (`title`) | 2 761 |
+| hit@1 · hit@8 · hit@50, S1–S6, default `k` | 6/6 · 6/6 · 6/6 | **6/6 · 6/6 · 6/6** | 6 |
+| hit@1 · hit@8 · hit@50, S1–S6, `k` = 50 | 6/6 · 6/6 · 6/6 | **6/6 · 6/6 · 6/6** | 6 |
+| KP rank, default `k` / `k` = 50 | 1 / 1 | **not delivered / 13** | 1 |
+| `okf check`, KP and S5 × both `k` | — | **4 of 4, 16 rules, 0 findings, exit 0** | 4 |
+
+hit@k is vegnormal-okf's `experiments/hitk_sk2.py`, run read-only against the
+scratch bundle with its five flags. Its payloads land at fixed
+`/tmp/hitk-sk2-<id>.json` paths and were moved out between runs. The same
+cells hold on the flagged and the unflagged build. On `de7849e`, `okf check`
+was also run over all 8 default-`k` payloads: 8 of 8, 0 findings.
+
+## 7. The known-positive, decomposed
+
+The KP question contains the document's own number and name. `consume`'s
+signal 1 is `title + concept_id.replace("/", " ")`, so once every concept id
+starts with `r761-prosesskoden/`, every concept matches those two question
+tokens, and the gold concept's distinguishing match on its own title
+disappears into a 2 761-way tie. With the UUID directory, the id matched
+nothing.
+
+| variant (all from `de7849e`, unflagged) | KP default `k` | KP `k` = 50 | S1–S6 |
+|---|---|---|---|
+| as built | not delivered | 13 | all rank 1 |
+| V1: every `description` line removed | not delivered | 13 | all rank 1 |
+| V2: only the directory renamed back to the UUID (root index link rewritten to match) | **1** | **1** | all rank 1 |
+| as built, `okf consume --rarity-weight` | **4** | **4** | all rank 1 |
+| base `56b00e7`, `--rarity-weight` | 6 | 6 | all rank 1 |
+
+`--rarity-weight` weighs a token by `log(N/df)`, and a token in every concept
+weighs 0. It delivers KP at the default `k` on this bundle with S1–S6 unmoved.
+It stays off: it is a ranking decision this round was fenced out of, and its
+wider measurement (`docs/2026-09-08-sjeldenhetsvekt.md`) was mixed. **Which way
+to go is the operator's.** The options are to keep the directory and repair
+the id-segment signal for a segment every concept shares, or to accept the row.
+
+## 8. Nothing else moved
+
+- **Five-document folder.** 5 = 5, 52 md. `diff -r` against the base build
+  differs in **one line of one file**: the `Converter` line in `log.md`, which
+  records the absolute path of the venv that ran it, and the two exports sit
+  in different directories. With that line ignored (`diff -r -I`), rc 0. The
+  folder holds 0 `.xml`, so it is a real known-negative.
+- **The four goldens.** `tests/test_segmented_golden.py` is green in the
+  working tree. In the export its fourth test is the one known red: it runs
+  `git status`, and an export has no repository.
+- **The pinned 43-document bundle.** `tests/test_default_bundle_pin.py`,
+  **7 passed** in the export with `GOLD_SET` copied in.
+- **Suite.** 1 602 → **1 658 passed**, 1 skipped (56 new). `ruff check src
+  tests tools`, `ruff format --check .` and `mypy --strict src` are clean, each
+  with its rc captured directly, after `git add` and after commit.
+- Nothing was written in `vegnormal-okf`. Its `git status` is empty, and the
+  two `hitk_sk2` bytecode files in its ignored `__pycache__` date from
+  2026-09-10.
+
+## Honesty limits
+
+- **N = 1 STS document.** "General" is a claim about the code: no document,
+  publisher or corpus is named in `src/`, and every rule is keyed to a schema
+  element. It is not a measurement over several documents. The fixtures are
+  hand-written from the measured document's shapes.
+- **The title choice rests on hit@k and bytes, not on what reads well**, and
+  hit@k could not separate the two candidates at all. The tie-break and the
+  flow-terminator fact decided it.
+- **The one-paragraph `description` limit is ours.** The spec asks for "a
+  single sentence" and sets no length. 942 characters is not one sentence, and
+  it is what the source wrote.
+- **The YAML rule is measured on 2 024 values from one document** against one
+  parser (PyYAML 6.0.3, YAML 1.1). A YAML 1.2 reader is not measured.
+- **KP's fall is measured on one question.** Whether a question that names its
+  own single-document bundle is common is not measured.
+- **`okf check` accepting a bundle is not a quality gate.** § 0 has a bundle
+  it accepts on 2 761 of 2 761 concepts that PyYAML refuses on the same count.
+- **The 43-document corpus was reasoned out, not rebuilt:** 0 `.xml` of 86,
+  and the five-document folder is the measured known-negative in its place.