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

AGENTS.md

@@ -38,14 +38,15 @@ Fall back to raw shell only when no skill covers it.
 ## Setup and testing
 
 - Run `apm install` to deploy this repo's own skills and agents into `.claude/skills/` and `.claude/agents/`. Both are gitignored install output, not authoring source — `plugins/<name>/.apm/` remains the only place to edit. The six dependencies in root `apm.yml` resolve from the holocron **remote**, unpinned against the default branch, so a `.apm/` edit is not visible to the running session until it is pushed and `apm update` re-runs (`apm install` deploys from `apm.lock.yaml` and does not re-resolve refs). Needs the network, and needs `apm_modules/` (which it materializes) left gitignored. `apm install` also configures the `obsidian` MCP server into the repo's `.mcp.json`, carried over from `plugins/bin/.mcp.json`.
-- Do not add repo-owned keys to `.claude/settings.json`. apm treats that file as its own deployed artifact: `apm audit --ci` replays the install into a scratch tree and diffs, so anything apm would not have written there — an `enabledPlugins` block, a real `hooks` entry — is permanent drift that fails the `apm-audit-ci` pre-push hook. Its committed content is whatever apm last wrote — `{"hooks": {}}` until kyberforge's `SessionStart` hook lands there, after which the merged hook entry is apm's output and belongs in the commit (ADR-0019). What does not change is that nothing repo-authored goes in the file. A hook you want in this repo is authored in `plugins/<name>/.apm/hooks/` and deployed by apm, never hand-written here. Machine-specific settings go in the gitignored `.claude/settings.local.json`, which apm does not deploy and the replay does not compare; shared enforcement belongs in `.pre-commit-config.yaml`.
+- Do not add repo-owned keys to `.claude/settings.json`. apm treats that file as its own deployed artifact: `apm audit --ci` replays the install into a scratch tree and diffs, so anything apm would not have written there — an `enabledPlugins` block, a real `hooks` entry — is permanent drift that fails the `apm-audit-ci` pre-push hook. Its committed content is whatever apm last wrote, which today is the merged `SessionStart` entry for kyberforge's `check-apm-current.sh` — apm's own output, and it belongs in the commit (ADR-0019). What does not change is that nothing repo-authored goes in the file. A hook you want in this repo is authored in `plugins/<name>/.apm/hooks/` and deployed by apm, never hand-written here. The file is also **excluded from `pretty-format-json`** in `.pre-commit-config.yaml` — the sixth and last alternation in that `exclude:` pattern, and the only one there for a reason other than "generated manifest". Mind which number you are quoting: six alternations, expanding to sixteen real files (3 root marketplace manifests, 2 per plugin × 6 plugins, plus this one). `pretty-format-json --autofix` sorts object keys while apm emits insertion order, so leaving the file in that hook's scope rewrites apm's output on the way into every commit and `apm audit --ci` then reports permanent drift on a file with an empty `git diff`. Do not tidy it out of that list; it is load-bearing (see `LESSONS.md`, 2026-08-14). Machine-specific settings go in the gitignored `.claude/settings.local.json`, which apm does not deploy and the replay does not compare; shared enforcement belongs in `.pre-commit-config.yaml`.
 - Keeping the install current is automatic but not free. Because the six dependencies are unpinned, deployed skills go stale whenever anyone merges. kyberforge ships a `SessionStart` hook that runs `apm outdated` at startup (~0.7s) and, when something is behind, runs `apm update --yes` and asks the host to re-scan skills (~10.4s). That rewrites `apm.lock.yaml`, so an unexplained modification to it after opening a session is expected, not a bug — commit or discard it deliberately. Note `apm install` alone will **not** pick up remote changes; it deploys from the lock. `apm update` is the command that re-resolves refs.
 - Install git hooks via `pc-run`, wiring all three stages — this repo's `.pre-commit-config.yaml` has no `default_install_hook_types`, so a plain install silently skips `commit-msg` (Conventional Commits) and `pre-push` (the 14-hook gate described below).
 - Install the `apm` CLI — four pre-push hooks shell out to it: `apm-marketplace-check`, `apm-audit-ci`, `apm-pack-check-clean`, and `check-plugin-content-sync` (via `scripts/sync-plugin-content.sh`, which wraps `apm pack`). `apm-marketplace-check` and `apm-pack-check-clean` are bare `apm …` hook entries and `apm-audit-ci` is a `bash -c` loop calling `apm` once per package, so without it the push dies with an unhelpful "command not found". Use `apm-install`, or `curl -sSL https://aka.ms/apm-unix | sh`; verify with `apm --version`.
 - Install `jq` — required by `scripts/check-manifests.sh` and `scripts/sync-plugin-content.sh`, both pre-push. These at least fail loudly (`Error: jq is required but not installed`).
-- Install `python3` — required by `scripts/skill-size-check.sh`, the `skill-size-check` pre-commit hook. It measures the *folded* `description` value: most descriptions here are `>`-block scalars, so a regex over the raw lines measures indentation and newlines instead of the value. Missing it fails the hook with an install pointer rather than skipping the ADR-0020 checks, which would be a vacuous green. In practice it is already present — pre-commit is itself a Python application. PyYAML is used when importable and is genuinely optional; a fallback reader covers the frontmatter shapes this corpus uses.
-- That hook enforces **two independent gate families** over `plugins/*/.apm/skills/*/SKILL.md`, and neither replaced the other. The agentskills.io spec backstop is unchanged: 500 lines and 2,770 words, counted over the **whole file including frontmatter**. ADR-0020 adds a context budget measured differently — `description` 250 chars SUGGESTION / 400 FAIL (it is preloaded into every session whether the skill fires or not), **body-only** word count 600 SUGGESTION / 900 FAIL (everything after the frontmatter's closing `---`), and every boundary-clause routing target resolving to a real skill or agent under `plugins/*/.apm/`. A file can sit well inside one family and fail the other. The hook is `verbose: true` so the SUGGESTION tier is audible — pre-commit prints nothing at all for a passing hook, and a SUGGESTION deliberately does not fail. `skill-audit`'s `validate.sh` holds a second copy of the four ADR-0020 constants; `tests/test-skill-size-check.sh` asserts the copies agree.
+- Install `python3` — required by `scripts/skill-size-check.sh`, the `skill-size-check` pre-commit hook. It measures the *folded* `description` value: most descriptions here are `>`-block scalars, so a regex over the raw lines measures indentation and newlines instead of the value. Missing it fails the hook with an install pointer rather than skipping the ADR-0020 checks, which would be a vacuous green. In practice it is already present — pre-commit is itself a Python application. **PyYAML is a hard requirement too**, not an optional accelerator: the hand-rolled fallback frontmatter reader has been removed, because a reader that mis-parses an unfamiliar scalar shape reports a clean pass on a file it never measured, which is the exact vacuous-green failure the `python3` check exists to avoid. `pip install pyyaml` if the hook reports it missing.
+- That hook enforces **two independent gate families** over `plugins/*/.apm/skills/*/SKILL.md`, and neither replaced the other. The agentskills.io spec backstop is unchanged: 500 lines and 2,770 words, counted over the **whole file including frontmatter**. ADR-0020 adds a context budget measured differently — `description` 250 chars SUGGESTION / 400 FAIL (it is preloaded into every session whether the skill fires or not), **body-only** word count 600 SUGGESTION / 900 FAIL (everything after the frontmatter's closing `---`), a missing, valueless or `null` `description:` (a hard FAIL, not a skip — a gate that declines to measure the one preloaded field reports green), every boundary-clause routing target resolving to a real skill or agent, and every `references/<file>.md` a body names actually existing. Target resolution walks 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 beat a real monorepo root. The universe is then every skill and agent under `<root>/plugins/*/`, plus the checked file's own apm package and whatever that package declares in its own `apm.yml` `dependencies.apm`; the **root** manifest's `dependencies:` block is not read, and no plugin here declares a cross-plugin apm dependency. Deployed `.claude/`/`.agents/` trees are consulted only when no authoring root exists — the consumer case. That matters because those trees are gitignored `apm install` output: resolution used to reach the four cross-plugin `gitea-*` → `git-*` targets through `.claude/skills/` alone, so the same commit measured 2 dangling targets on a developer machine and 6 on a fresh clone. It no longer does — verified by running the hook over a tree holding only `plugins/` and the root `apm.yml`, which reports findings identical to the working tree (26 description / 9 body / 2 dangling / 0 missing references / 58 SUGGESTIONs). Three further checks are SUGGESTION-only: a description with no boundary clause at all, a `## Gotchas` section with more than five entries, and a `## Gotchas` section over 25% of the body. A file can sit well inside one family and fail the other. The hook is `verbose: true` so the SUGGESTION tier is audible — pre-commit prints nothing at all for a passing hook, and a SUGGESTION deliberately does not fail. `skill-audit`'s `validate.sh` holds a second copy of the four ADR-0020 constants; `tests/test-skill-size-check.sh` asserts the copies agree.
 - **Those ADR-0020 gates ship hot, with no baseline file.** 26 of 39 descriptions and 9 of 39 bodies currently exceed their FAIL tier, so editing one of those skills *for any reason* means retrofitting it to the contract first — a one-line fix to `gitea-prs` cannot be committed until that skill complies. This is deliberate, and the retrofit is tracked as Gitea issue #99. Check where a skill stands before starting: `pre-commit run skill-size-check --all-files`.
+- **A second gate ships hot alongside it, and `skill-size-check` will not warn you about it.** `Kyberforge.CompositionNote` — the ADR-0020 Vale rule banning composition and architecture prose from a description — currently fires **10 errors across four skills**: `gitea-issues`, `gitea-labels-milestones`, `gitea-prs` and `gitea-workflow`. Every Vale rule here is `level: error` with no ignorable tier, so touching any of those four means fixing its prose findings as well as its size findings. Scoping a retrofit off `skill-size-check` output alone will leave you blocked at the second gate. Check both: `pre-commit run --all-files`.
 - Install the `vale` binary — required by the `vale-audit-prefilter-skill`/`-agent` pre-commit hooks. Their `files:` patterns are `.apm/`-scoped: `^plugins/[^/]+/\.apm/skills/[^/]+/SKILL\.md$` and `^plugins/[^/]+/\.apm/agents/[^/]+\.agent\.md$`. Only the authoring source triggers them — a `SKILL.md` in the generated mirror matches neither pattern, so prose findings surface only when you edit the file you are supposed to be editing. Without the binary the hooks fail with a bare "command not found" and no install pointer. `brew install vale` (macOS), `snap install vale` (Linux), `choco install vale` (Windows), or see https://vale.sh/docs/vale-cli/installation/. No `vale sync` needed — the `Kyberforge` styles are committed under `plugins/kyberforge/.apm/skills/{skill-audit,agent-audit}/assets/vale/styles/`, not downloaded packages (see ADR-0014).
 - `vale` is also a **pre-push** dependency, not only pre-commit. `check-vale-style-sync` runs six glob-coverage probes by invoking `vale --config` — they are the only assertions in it that catch a `.vale.ini` glob typo, the failure mode where every text-level check stays clean while vale lints zero files. Missing `vale` is therefore a hard failure there. The opt-out is `CHECK_VALE_STYLE_SYNC_ALLOW_MISSING_VALE=1`, and it is **not** `SKIP=`: the hook still runs and still asserts everything verifiable from file text, but the six probes do not, and its summary says so explicitly — `Vale style sync check passed (text-level only, vale unavailable): … 0 glob probe(s) verified`. Use it only on a machine that genuinely cannot install `vale`, and read that summary line as "the glob axis was not checked", not as a pass.
 - Run `bash tests/run-tests.sh` before considering any change done — it runs every `test-*.sh` script in the repo plus the bats suite (`--bats-only` for just bats). First run auto-initializes the bats submodules; no manual `git submodule update` needed.
@@ -53,7 +54,7 @@ Fall back to raw shell only when no skill covers it.
 - `tests/run-bats.sh` derives the set of `.bats` files it expects from `git ls-files`, so a `.bats` file deleted from the worktree but still tracked in the index fails the run rather than silently shrinking the suite. Remove one with `git rm` (or stage the deletion) when the removal is intentional; an untracked new `.bats` file is picked up and needs no ceremony. Both discovery walks (`tests/run-bats.sh` and `tests/run-tests.sh`) exclude `apm_modules/`: `apm install` materializes a full copy of every plugin there, and running a dependency's copy of a `.bats` file breaks its relative path to the bats helpers — 167 spurious failures before the exclusion landed.
 - Pushing runs 14 repo-defined pre-push hooks, not just the test suite — `run-tests` and `check-manifests`, plus generated-content drift gates (`check-plugin-content-sync`, `check-marketplace-mirror-sync`, `check-vale-style-sync`, `check-scope-walkup-sync`, `check-executables-allow-sync`), artifact validators (`check-apm-agents-valid`, which runs agent-audit's `validate.sh` over every real `plugins/*/.apm/agents/*.agent.md`), apm's own gates (`apm-marketplace-check`, `apm-audit-ci`, `apm-pack-check-clean`), host validators (`validate-plugins`, `validate-marketplace`, both needing the `claude` CLI), and `check-release-needed`. `check-executables-allow-sync` is the odd one in that first group — it guards a silent failure rather than drift in generated text. apm gates a package's `hooks/` and `bin/` on an exact `<package>#<version>` lookup in root `apm.yml`'s `executables.allow`, with no wildcard and no version-less form, so bumping `plugins/kyberforge/apm.yml`'s `version:` without bumping the key errors nowhere: the entry simply stops matching, kyberforge's `SessionStart` hook stops deploying, and the install goes quietly stale — the failure ADR-0019 records as live. Run `pre-commit run --hook-stage pre-push --all-files` locally — one command, the whole gate. That command reports **16**, not 14: pre-commit's own `meta` hooks, `check-hooks-apply` and `check-useless-excludes`, declare no `stages:` and so run at every stage including this one.
 - `apm-audit-ci` runs `apm audit --ci` once per manifest — the root one and each of the six plugin packages — because the root-only invocation audits the marketplace manifest and **nothing else**, and `apm-pack-check-clean` does not parse plugin `dependencies:` blocks either (verified: a malformed one passes `apm pack --check-versions --check-clean --dry-run` and fails `apm audit --ci` in that package's directory). It verifies two things and claims no more: each `apm.yml` parses as a valid APM manifest, and any package declaring dependencies has a consistent `apm.lock.yaml`. It does **not** enforce an org policy — apm discovers one from the git remote and only understands github.com and Azure DevOps, so against this repo's self-hosted Gitea remote it prints `No org policy found at unknown; enforcement skipped`. Do **not** "fix" that with `policy.fetch_failure_default: block` in `apm.yml`: it was tested and rejected, because with no reachable policy source it makes the hook exit 1 on every push forever.
-- `check-apm-agents-valid` derives its expected agent-file set from `git ls-files` (same pattern as `tests/run-bats.sh`), so an agent file deleted from the worktree but still tracked fails the run, and discovering zero agent files is an error rather than a pass. An untracked new agent file is still validated — the derivation is one-directional on purpose, so uncommitted work is not blocked but also cannot bypass the gate. Agents take the ADR-0020 description gates (`agent-audit`'s `validate.sh` holds its own copy of those two constants) and, deliberately, **no** body word gate: an agent body becomes the system prompt of a fresh context rather than competing with the caller's live conversation, so the 900-word FAIL does not transfer. A bats test pins that absence — adding a body gate there contradicts the ADR rather than fixing an inconsistency.
+- `check-apm-agents-valid` derives its expected agent-file set from `git ls-files` (same pattern as `tests/run-bats.sh`), so an agent file deleted from the worktree but still tracked fails the run, and discovering zero agent files is an error rather than a pass. An untracked new agent file is still validated — the derivation is one-directional on purpose, so uncommitted work is not blocked but also cannot bypass the gate. Agents take the ADR-0020 description gates (`agent-audit`'s `validate.sh` holds its own copy of those two constants) and, deliberately, **no** body word gate: an agent body becomes the system prompt of a fresh context rather than competing with the caller's live conversation, so the 900-word FAIL does not transfer. A bats test pins that absence in `agent-audit`'s validator — adding a body gate there contradicts the ADR rather than fixing an inconsistency. Be precise about the scope of that guarantee, though: it holds for the **validator**, not for the shared script. `scripts/skill-size-check.sh` applies its body gate to whatever path it is handed, and `bash scripts/skill-size-check.sh plugins/*/.apm/agents/*.agent.md` exits 1 today with 900-word body FAILs on `git-orchestrate` (933), `gitea-orchestrate` (1,199) and `apm-orchestrate` (1,080). Agent files escape only because the hook definitions filter on `SKILL.md` — a file-pattern accident that happens to implement the design, not the design itself. Do not "extend" that hook's `files:` pattern to cover agents on the assumption that the script already knows the difference.
 - **Two** pre-push hooks need the network, for one shared reason: root `apm.yml`'s `marketplace.packages[]` contains exactly one remote entry (`mattpocock-skills`, `source: mattpocock/skills`), and resolving it needs a `git ls-remote`. `apm-marketplace-check` resolves every entry and is `always_run`, so it fails with `No cached refs (offline)`. `apm-pack-check-clean` (`apm pack --check-versions --check-clean --dry-run`) re-resolves the same entry and fails with `Error: Git network timeout during ls-remote`. Pinning the entry to an exact version does **not** remove the call — an exact pin still ls-remotes. `--offline` rescues neither. To push without a network, skip both using pre-commit's own mechanism: `SKIP=apm-marketplace-check,apm-pack-check-clean git push`. Skip those two alone — verified under `unshare -rn`, the other twelve pre-push hooks pass offline because they are real local checks (`check-executables-allow-sync` landed after that run, but reads two local manifests and makes no network call), and adding one of them to `SKIP` disarms it silently. `apm-audit-ci` calls `apm` too but stays local: its org-policy discovery resolves nothing on this remote before any network call, so it does not join the pair above.
 - Author commits with `git-commits` — it validates Conventional Commits (enforced at `commit-msg`) for you.