docs: make ADR-0020 match what actually shipped, and record what did not

The ADR was written against base commit `f9b919d` and then not updated as the
implementation moved, so several of its numbers were measuring one thing and being
read as another — the exact conflation the ADR exists to stop, reproduced inside
it. Corrections, all reproducible now that each figure states its method:

- The preload tax is 23,427 chars / ~5,900 tokens, not 23,612 / ~6,200.
- `MAX_WORDS=2770` is a density proxy for the agentskills.io ~5,000-token ceiling,
  not "2× p90". Neither percentile reaches it: 2× the body-only p90 is 2,698 and
  2× the whole-file p90 is 3,052. Reading it as a percentile pairs a whole-file
  gate against a body-only distribution.
- `apm-workflow` is a 421-word body; 554 is its whole-file count. `skill-author`
  and `agent-author` were 2,623 and 2,582 body words — 2,760 and 2,758 whole-file,
  which is where "within twelve words of the gate" comes from. Two numbers for one
  file is the point, and only one of them is what either gate measures.
- Every `file:line` citation now says it resolves against `f9b919d`, since this
  change rewrites most of the cited files.

Three things the ADR asserted that no validator implemented are now filed by tier
in an exhaustive enforcement table — deterministic, prose-pattern, or auditor
judgment — because a rule filed under "Enforcement" that nothing enforces is the
failure mode this ADR is most exposed to. The Gotchas entry count moves to
SUGGESTION to match the script; the paraphrase FAIL is marked as an auditor's,
since semantic equivalence is not pattern-matchable.

Two gaps recorded rather than quietly left:

- The agent body-gate exemption lives in `agent-audit`'s validator and in the
  `skill-size-check` hook's `SKILL.md`-only `files:` pattern — *not* in
  `scripts/skill-size-check.sh`, which measures whatever path it is handed and
  today reports 900-word body FAILs on `git-orchestrate` (933),
  `gitea-orchestrate` (1,199) and `apm-orchestrate` (1,080). Agents escape by file
  pattern, not because the script knows the difference, so widening that pattern
  would silently enforce a gate this ADR declines to set.
- The `skill-audit`/`agent-audit` merge is deferred to #101. This change made the
  split deeper, not shallower: the dispatch retrofit took them from 3 and 4
  reference files to 7 and 8, and their two same-named `description-quality.md`
  files now differ on 100 of ~120 lines after normalising skill/agent. The merge
  reopens ADR-0008 and touches every call site in `skill-author`, `agent-author`
  and `forge`, so it is its own change. #100 carries the dangling-target fixes.

AGENTS.md and CONTEXT.md take the same corrections plus the two live setup
changes: PyYAML is now a hard requirement rather than an optional accelerator (a
fallback that mis-parses an unfamiliar scalar shape reports a clean pass on a file
it never measured), and `.claude/settings.json`'s `pretty-format-json` exclusion is
documented as load-bearing rather than as a tidy-up candidate.

LESSONS.md's autofix entry is corrected on its own provenance, which it got wrong
in both directions. `git log --date=iso` puts the introducing commit at 18:47 and
the fix at 21:54 — three hours, not "weeks" — and `git branch -a --contains` puts
the introducing commit on this branch only, not on main. It was manufactured
inside the same PR that diagnosed it. The added lesson is that "pre-existing" is a
claim about history and history is queryable: a defect found while working on a
branch feels inherited, and the feeling is not evidence.

Refs: ADR-0020, #99, #100, #101

CONTEXT.md

@@ -27,13 +27,13 @@ A separate product (separate repo) for browsing, editing, and configuring AI dev
 Reusable slash commands for AI coding tools, defined as `SKILL.md` files following the [Agent Skills open standard](https://agentskills.io). Authored at `plugins/<plugin-name>/.apm/skills/<skill-name>/SKILL.md` and reaching a host by one of two install paths: `apm install`, which deploys the skill directory to `.claude/skills/<skill-name>/` (this repo's own path — see "apm-consumed install"), or `claude plugin install <name>@<marketplace>`, which caches the whole plugin (still supported for external consumers). Skills are self-contained — they cannot reference files outside the plugin directory after install-time caching. The two paths name skills differently: apm deploys a plain project skill (`skill-audit`), a plugin install namespaces it (`kyberforge:skill-audit`).
 
 ### Preload tax
-The always-on context cost of every installed skill's `name` + `description`, which sit in the agent's context from the first token of every session whether or not the skill is invoked. Measured 2026-08-14 at 23,612 chars (~6,200 tokens) across 39 skills, plus 1,325 chars for 4 agents. Non-routing frontmatter (`metadata.source_keys`, `category`, `version`) is **not** part of it — the model-visible skill listing carries only `name` and `description`, which supersedes `LESSONS.md:63` on this host. Bodies are not part of it either; they are charged on invocation.
+The always-on context cost of every installed skill's `name` + `description`, which sit in the agent's context from the first token of every session whether or not the skill is invoked. Measured 2026-08-14 against base commit `f9b919d` at 23,427 chars (~5,900 tokens) across 39 skills, plus 1,325 chars for 4 agents. Method, so it can be re-run: sum `len(name) + len(description)` over each `plugins/*/.apm/skills/*/SKILL.md` frontmatter with `>` block scalars folded to the value the host loads, at ~4 characters per token. Non-routing frontmatter (`metadata.source_keys`, `category`, `version`) is **not** part of it — the model-visible skill listing carries only `name` and `description`, which supersedes `LESSONS.md:63` on this host. Bodies are not part of it either; they are charged on invocation.
 
 ### Skill context contract
-The authoring rules that hold the preload tax and body size down, set by ADR-0020. A description carries a trigger clause, at most one capability clause, and a boundary clause of the form `Not <thing> → <skill-name>` naming a resolvable target — nothing else. Capability enumeration, output formats, and composition notes ("composes X rather than duplicating Y") belong in the body or `README.md`; a description that summarises workflow is a correctness hazard, not just a cost, because agents act on it instead of reading the body. Sizes are two-tier and sit *below* the agentskills.io spec limits, which stay unchanged as conformance backstops: description 250 SUGGESTION / 400 FAIL (spec 1,024); body 600 SUGGESTION / 900 FAIL (spec 2,770 words / 500 lines). Conflating the quality gate with the spec ceiling is what let `skill-author` and `agent-author` grow to within twelve words of 2,770.
+The authoring rules that hold the preload tax and body size down, set by ADR-0020. A description carries a trigger clause, at most one capability clause, and a boundary clause of the form `Not <thing> → <skill-name>` naming a resolvable target — nothing else. "Resolvable" is decided by walking up *from the file being checked* to an **authoring root** — the nearest ancestor holding `plugins/*/.apm/{skills,agents}`, falling back to the nearest `.git`, in two passes so a nested `.git` cannot outrank a real monorepo root. The universe is then every skill and agent under `<root>/plugins/*/` (sibling plugins resolve against each other, which is what a monorepo means), plus the checked file's own apm package and that package's own declared `dependencies.apm`. The **root** manifest's dependency list is never consulted, and no plugin here declares a cross-plugin apm dependency. Deployed `.claude/`/`.agents/` trees count only when there is no authoring root at all — the consumer case. The property this buys is that one commit gets one verdict: those trees are gitignored `apm install` output, so resolving through them made the same commit report 2 dangling targets on a developer machine and 6 on a fresh clone, which a gate shipping hot with no baseline cannot do. A `${BASH_SOURCE}`-relative repo root is the other half of the same defect and is gone — it leaked this repo's 39-skill universe into consumer repos running the hook through pre-commit. A *missing* boundary clause is a SUGGESTION rather than a failure, for skills and agents alike — some skills genuinely have no near-miss sibling. A *missing or empty description* is the opposite: a hard FAIL in all three validators, because a gate that merely declines to measure the one preloaded field reports green. Capability enumeration, output formats, and composition notes ("composes X rather than duplicating Y") belong in the body or `README.md`; a description that summarises workflow is a correctness hazard, not just a cost, because agents act on it instead of reading the body. Sizes are two-tier and sit *below* the agentskills.io spec limits, which stay unchanged as conformance backstops: description 250 SUGGESTION / 400 FAIL (spec 1,024); body 600 SUGGESTION / 900 FAIL (spec 2,770 words / 500 lines). Conflating the quality gate with the spec ceiling is what let `skill-author` and `agent-author` grow to within twelve words of 2,770.
 
 ### Dispatch body
-The body pattern a skill with two or more mutually exclusive flows must use: the body carries only the dispatch table and the gates common to every branch, and each flow lives in its own self-contained `references/` file. Named for `apm-workflow` (554-word body, 3,006 words of references), which arrived at it independently and is the repo's exemplar. Its absence is the characteristic defect — `skill-author` inlines both its create and improve flows, and `agent-author` carries 50-60 lines marked inapplicable by their own headers on any single run.
+The body pattern a skill with two or more mutually exclusive flows must use: the body carries only the dispatch table and the gates common to every branch, and each flow lives in its own self-contained `references/` file. Named for `apm-workflow` (421-word body, 3,006 words of references), which arrived at it independently and is the repo's exemplar. Its absence was the characteristic defect at the time ADR-0020 was written: `skill-author` inlined both its create and improve flows, and `agent-author` carried 50-60 lines marked inapplicable by their own headers on any single run. Both were retrofitted to dispatch tables in the change that carries the ADR — `skill-author` went 2,623 body words to 595 and `agent-author` 2,582 to 616 — so they are now worked examples of the pattern rather than counter-examples of it. The 39-skill corpus at large is not: 9 bodies still exceed the 900-word FAIL (issue #99).
 
 ### Hand-invoked skill
 A skill reached only by typing its slash command, declared with `disable-model-invocation: true`. The host withholds it from the model-visible skill listing entirely, so it pays no preload tax and its `description` becomes human-facing text rather than a trigger list. `zoom-out` is the worked example: apm passes the flag through verbatim to both install paths, and the skill is absent from the router while `/zoom-out` still works. Choosing model-invoked vs. hand-invoked is the first question `skill-author` asks, because it determines whether a description needs triggers at all.
@@ -100,7 +100,7 @@ Wiring Vale as a deterministic prefilter for `skill-audit`/`agent-audit`'s Descr
 
 Both skills' Step 1, and the `vale-audit-prefilter-skill`/`-agent` pre-commit hooks, call each copy's own `scripts/vale-wrap.sh` rather than `vale` directly — a workaround for a confirmed Vale 3.15.2 limitation (see `vale-config`'s Gotchas): `text.frontmatter.description` silently stops matching on most — not all — multi-line descriptions. Verified by reproduction, not assumed: `>` folded scalars, plain (unquoted) continuation lines, and single- or double-quoted multi-line scalars all yield 0 alerts and exit 0 on a deliberately-bad fixture, while a `|` literal block spanning the same 2+ lines lints normally (alerts fire, exit 1). The wrapper flattens those three broken forms to one physical line in a scratch copy (padding with blank lines so every other line number is unchanged) before handing off to real `vale`; `|` literal blocks and single-line descriptions pass through untouched, already linting correctly. The plain and quoted forms previously passed silently — unflattened and unmatched — so a bad description in either sailed through the prefilter. Handed no `--config` at all, the wrapper falls back to its own sibling `assets/vale/.vale.ini`, located from `${BASH_SOURCE[0]}` rather than from the cwd — which is why both manifests' `entry:` is now the bare script path with no argument after it. pre-commit prefixes only `entry[0]` with the hook-repo clone path (`cmd = (prefix.path(cmd[0]), *cmd[1:])`), so every later argument resolves against the *consuming* repo's root: a `--config` in `.pre-commit-hooks.yaml` pointed at a path no consumer has and hard-failed every external run with `E100 [--config] Runtime error`. `.pre-commit-config.yaml` drops the argument too, deliberately keeping the two entries identical — the local `repo: local` hook resolved its `--config` correctly only because the consuming repo *was* this repo, and that divergence is why three review rounds exercised a path no external consumer takes and missed the defect. An explicit `--config` still wins, in all three argv forms (`--config X`, `--config=/abs`, `--config=rel`), and a relative one still resolves against the caller's cwd, matching bare `vale`, not the repo root. Both audit skills' Step 1 now passes no `--config` either: it resolves the script relative to the skill's own directory so the call works from an installed plugin cache, but a relative `--config` alongside it would still resolve against the cwd, yielding `E100 Runtime error ... does not exist` and exit 2 — which both skills' fallback misreads as "vale unavailable" and silently downgrades to full LLM judgment. `tests/test-vale-wrap.sh` regression-tests this against skill-audit's copy specifically (its fixtures are all `SKILL.md`-shaped, and only skill-audit's `.vale.ini` has that glob section). Each `.vale.ini`'s section globs are path-agnostic (`[**/SKILL.md]` for skill-audit's copy; `[**/agents/*.md]`/`[**/*.agent.md]` for agent-audit's) and do no scoping on their own: Vale's `*` crosses `/`. Scoping comes from each pre-commit hook's own `files:` regex and from the audit skills passing one explicit file per invocation. The two manifests scope differently on purpose: this repo's `.pre-commit-config.yaml` pins its own layout — `^plugins/[^/]+/\.apm/skills/[^/]+/SKILL\.md$` for `-skill`, `^plugins/[^/]+/\.apm/agents/[^/]+\.agent\.md$` for `-agent` — while the shipped `.pre-commit-hooks.yaml` stays layout-agnostic for external consumers whose skills live anywhere, using `(^|/)SKILL\.md$` and `(^|/)agents/[^/]+\.md$|\.agent\.md$`. Both manifests split the prefilter into two hooks precisely because one combined hook pointed at only one copy would silently 0-file-skip the other file type. A `SKILL.md` outside `plugins/` (e.g. project-scope `.claude/skills/foo/SKILL.md`) still matches `[**/SKILL.md]` and gets linted normally — the globs constrain filename shape, not location. Vale reports 0 files only when the path it is handed matches no glob section at all: a differently-named file, or a directory argument holding nothing that matches. That run prints `✔ 0 errors ... in 0 files.` and exits 0, indistinguishable from a clean pass, so both audits treat a 0-file Vale run as NOT RUN and fall back to full LLM judgment.
 
-This scope expands per ADR-0013: one cherry-picked low-noise `write-good`/`alex` rule landed in `styles/Kyberforge`, `Kyberforge.SentenceOpenerThereIs` (22 held-out hits, both in-corpus hits clean rewrites, zero suppressions). A second, `Kyberforge.VagueQualifier`, was cherry-picked and then deleted: 2 hits across the 41 skill/agent files, one marginal and one an unfixable false positive (`caveman/SKILL.md` quotes `of course` as an example of filler — a mention, not a use) that forced the repo's only Vale suppression comments. Also new is a sibling pre-commit hook, `skill-size-check` (`scripts/skill-size-check.sh`), enforcing agentskills.io's `SKILL.md` ceiling as two blocking gates: `MAX_LINES=500` and `MAX_WORDS=2770` (a word-count proxy for the 5,000-token limit, calibrated to the densest prose measured in this repo — 1.81 tokens per word — so even a worst-case `SKILL.md` at the ceiling stays under 5,000 tokens). Both are inclusive, and `skill-audit/scripts/validate.sh` checks the same pair on the same terms, so a `SKILL.md` can no longer pass its own audit yet be blocked by the commit hook. Scoped to `^plugins/[^/]+/\.apm/skills/[^/]+/SKILL\.md$` only, same as `vale-audit-prefilter-skill`, so it never lints `docs/research/examples/` reference skills. It's also exposed in the root-level `.pre-commit-hooks.yaml` as `kyberforge-skill-size-check` — it has no external asset dependency, so it needed no relocation, only exposure to external consumers. File scope (`SKILL.md` + agent files) and enforcement model (rules land directly in `styles/Kyberforge`, blocking immediately, no trial tier) stay unchanged; governance.md/CONTROLS.md were evaluated and excluded as rule sources (nothing prose-pattern-matchable to mine). House convention: banned phrasing that must be mentioned rather than used goes in backticks or a fenced code block — Vale skips code spans and fences, so no suppression is needed; inline `<!-- vale Rule = NO -->` (HTML-comment form; the MDX `{/* */}` form does not work in plain Markdown) is the fallback only where backticking is impossible.
+This scope expands per ADR-0013: one cherry-picked low-noise `write-good`/`alex` rule landed in `styles/Kyberforge`, `Kyberforge.SentenceOpenerThereIs` (22 held-out hits, both in-corpus hits clean rewrites, zero suppressions). A second, `Kyberforge.VagueQualifier`, was cherry-picked and then deleted: 2 hits across the skill/agent corpus as it stood at the time of that measurement (2026-08-08, before the `.apm/` restructure), one marginal and one an unfixable false positive (`caveman/SKILL.md` quotes `of course` as an example of filler — a mention, not a use) that forced the repo's only Vale suppression comments. A third, `Kyberforge.CompositionNote`, landed with ADR-0020 and bans architecture and composition prose from a description; it is `level: error` like the rest, and it currently fires 10 times across `gitea-issues`, `gitea-labels-milestones`, `gitea-prs` and `gitea-workflow`, so `pre-commit run --all-files` is red on prose as well as on size until issue #99 lands. Also new is a sibling pre-commit hook, `skill-size-check` (`scripts/skill-size-check.sh`), which carries **two independent gate families that must not be conflated** (see "Skill context contract"). The agentskills.io spec backstop is `MAX_LINES=500` and `MAX_WORDS=2770`, both inclusive and both counting the **whole file including frontmatter** (2,770 is a word-count proxy for the 5,000-token limit, calibrated to the densest prose measured in this repo — 1.81 tokens per word — so even a worst-case `SKILL.md` at the ceiling stays under 5,000 tokens; it is not a percentile of the corpus). ADR-0020 adds a context budget measured differently: description characters 250 SUGGESTION / 400 FAIL, **body-only** words 600 SUGGESTION / 900 FAIL, plus deterministic checks that every boundary routing target resolves, that a body's named `references/<file>.md` all exist, and — SUGGESTION-tier — that a boundary clause is present at all, that `## Gotchas` holds at most five entries, and that it stays under 25% of the body. `skill-audit/scripts/validate.sh` and `agent-audit/scripts/validate.sh` hold their own copies of the shared constants and `tests/test-skill-size-check.sh` asserts the copies agree, so a `SKILL.md` can no longer pass its own audit yet be blocked by the commit hook. Agents take the description gates and no body word gate. `python3` **and PyYAML** are hard requirements — the earlier hand-rolled frontmatter fallback is gone, because a fallback that silently mis-parses a scalar shape reports a vacuous pass. Scoped to `^plugins/[^/]+/\.apm/skills/[^/]+/SKILL\.md$` only, same as `vale-audit-prefilter-skill`, so it never lints `docs/research/examples/` reference skills. It's also exposed in the root-level `.pre-commit-hooks.yaml` as `kyberforge-skill-size-check` — it has no external asset dependency, so it needed no relocation, only exposure to external consumers. File scope (`SKILL.md` + agent files) and enforcement model (rules land directly in `styles/Kyberforge`, blocking immediately, no trial tier) stay unchanged; governance.md/CONTROLS.md were evaluated and excluded as rule sources (nothing prose-pattern-matchable to mine). House convention: banned phrasing that must be mentioned rather than used goes in backticks or a fenced code block — Vale skips code spans and fences, so no suppression is needed; inline `<!-- vale Rule = NO -->` (HTML-comment form; the MDX `{/* */}` form does not work in plain Markdown) is the fallback only where backticking is impossible.
 
 ### LESSONS.md
 Long-loop feedback log for patterns observed across sessions. Three or more entries on the same pattern graduate to the relevant standing file (e.g. a coding convention, a governance rule). Updated by the session-handoff skill or directly by the human. Lives at the repo root.