holocron/docs/adr/0013-vale-harness-scope-and-rule-sources.md

# Vale audit prefilter expands into a plugin-content harness, scoped to prose-pattern rules only

Issue #84 wired Vale as a deterministic prefilter for `skill-audit`/`agent-audit`, scoped to
exactly four pattern-matchable checks (imperative description opener, vague capability wording,
generic reference-pointer padding, Copilot's dead `Use proactively` phrasing), documented only in
CONTEXT.md's "Vale audit prefilter" section — never its own ADR — and explicitly excluding body
discipline, near-miss exclusion strength, and control calibration as non-goals. This ADR records a
deferred PR #85 review item to broaden that coverage, retroactively captures #84's own rationale
(since it was never recorded as a decision in its own right), and layers the expansion on top
without reversing or weakening the original four rules.

**2026-08-17 amendment.** The CONTEXT.md section named above no longer holds that documentation.
CONTEXT.md was cut back to a glossary and the prefilter's mechanics — the two-copy style layout,
`vale-wrap.sh`, the `--config` argv defect, the rule inventory, and the 0-files-means-NOT-RUN
fallback — moved to `docs/spec/gates.md`. Read that file, not CONTEXT.md, for the harness itself;
this ADR still owns the scope decision.

**File scope stays the same.** `SKILL.md` plus agent files (`**/agents/*.md`,
`**/*.agent.md`) only — matching the existing prefilter's globs. Skill-level
`README.md` files and `plugin.json` manifests are not added: README.md files are navigational, not
spec-governed content, and `plugin.json` is JSON, not prose Vale can meaningfully lint.

**Rule categories are prose-pattern-matchable only.** Structural, schema, and security concerns
stay out of this Vale-based harness because this repo already has dedicated tools for them:
`skill-frontmatter` (required frontmatter fields), `validate-plugins`/`validate-marketplace`
(`claude plugin validate --strict`, schema), and `gitleaks`/`detect-private-key` (secrets).
Duplicating those concerns as Vale rules would fight tools that already own them better.

**Governance docs are excluded as a rule source.** `docs/research/governance_principles/CONTROLS.md`
and `governance.md` were investigated and found to contribute nothing minable: CONTROLS.md is
org/CI-infrastructure controls (secret scanning, dependency/license scanning, agent permission
scoping, audit logging, human approval gates, periodic reviews) — none of it is a prose pattern
expressible as a Vale rule against SKILL.md/agent-file text, and what it does cover is either
already handled elsewhere (gitleaks) or genuinely out of scope for a plugin-content prose harness
(dependency/license scanning is a code-dependency concern, not skill authoring).

**Spec-derived custom rules stay mostly as-is.** Re-reading agentskills.io's
`optimizing-descriptions.md` and `skill-authoring.md`, plus `claude-code-plugins/agent-definition.md`
and `github-copilot-plugins/agent-definition.md`, found that the existing four Kyberforge rules
already cover the pattern-matchable surface those specs describe. The remaining spec guidance —
calibrating control vs. giving freedom, avoiding menus of options, coherent skill scope, moderate
detail level — is semantic judgment, already `skill-audit`'s job via LLM review, not new lintable
rules. One confirmation surfaced: Claude Code's `Use proactively` phrasing is meaningful for `.md`
agent files (it triggers auto-invocation), unlike Copilot's `.agent.md` files where it's dead
phrasing — so `KyberforgeCopilot/ProactivePhrase`'s existing `.agent.md`-only scope is correct and
must not be extended to `.md` files.

**`write-good`/`alex` are trialed, not adopted wholesale.** These built-in/third-party Vale
packages are tuned for general blog-style prose (passive voice, weasel words, wordy phrases) and
are expected to be noisy against this repo's terse, imperative instruction-file corpus. Only
individual rules proven low-noise against the existing corpus get cherry-picked into
`styles/Kyberforge`; the packages are never referenced wholesale in `BasedOnStyles`.

**A new non-Vale check closes a real gap.** `skill-authoring.md` states `SKILL.md` should stay
under 500 lines / 5,000 tokens — currently unenforced anywhere in this repo. This is a whole-file
length ceiling, not a text pattern, so it isn't a Vale rule — it becomes a new deterministic script
and pre-commit hook, sibling to the existing `skill-frontmatter` hook.

**Rules land directly in `styles/Kyberforge`, enforcing immediately.** No trial/report-only tier
is introduced (see Considered Options). "Enforcing immediately" holds only because every rule in
both styles is `level: error`: Vale's exit code keys on `error`-level alerts alone, so a
`warning`- or `suggestion`-level rule prints an alert and still exits 0, and pre-commit suppresses
output from hooks that pass — such a rule is invisible and blocks nothing. Every Vale alert is
therefore a FAIL, in the audit skills and in the blocking pre-commit hook alike, with no ignorable
tier; that matches every other gate in this repo (shellcheck, the test suite,
conventional-pre-commit). The implementation pass finalizes the cherry-picked
`write-good`/`alex` rules and any new spec-derived rule wording, runs the full set against the
existing SKILL.md/agent-file corpus, fixes any resulting violations across that corpus, and lands
the rule changes and the corpus fixes as one atomic commit — the same enforcement model as the
original four rules, never a partial or opt-in state.

## Considered options

**Phased rollout via a separate trial style + config (rejected).** A `styles/KyberforgeTrial/`
directory plus a parallel `.vale.trial.ini` (mirroring the root config's globs but with
`BasedOnStyles = Kyberforge, KyberforgeTrial`) would let new rules be swept report-only via
`lint-runner`/`vale-run` before promotion into the enforcing `styles/Kyberforge` + root
`.vale.ini`. This was considered because `BasedOnStyles = Kyberforge` activates every rule file
under that directory automatically — there's no partial/opt-in application within a style, so a
rule dropped straight into `styles/Kyberforge` goes live in the blocking pre-commit hook
immediately. Rejected in favor of finalizing rules directly and fixing violations via subagent
before committing: simpler, no new trial-config machinery to build or maintain — at the cost of no
standing report-only tier for future candidate rules. Note that the first implementation shipped
graded severities (`error`/`warning`/`suggestion`) and thereby recreated the rejected option by
accident: the five non-`error` rules never affected an exit code and never surfaced output through
a passing pre-commit hook, so they were a report-only tier that reported to nobody. Flattening
every rule to `level: error` is what actually implements this decision.

## Consequences

- `styles/Kyberforge/` gained one new rule file, cherry-picked from `write-good`/`alex` as
  low-noise against this repo's corpus: `SentenceOpenerThereIs.yml` (22 hits across 273 held-out
  markdown files; both in-corpus hits were clean rewrites, needing no suppression).
- A second candidate, `VagueQualifier.yml`, was cherry-picked and then dropped. Against the 41
  skill/agent files it hit twice: one marginal real finding (`prototype/SKILL.md`, "very different"
  → "fundamentally different") and one false positive (`caveman/SKILL.md`, which *quotes* `of
  course` as an example of filler — a mention, not a use) that no rewrite could clear, forcing the
  repo's only Vale suppression comments. Of its 15 held-out hits, 9 were in `docs/research/examples/`
  (out-of-scope upstream material) and the remaining 6 were the word "very" in two idioms in a
  single research doc, each already adjacent to the hard number carrying the fact. One marginal
  catch does not pay for a permanent suppression, so the rule is deleted and this ADR's
  "cherry-picked rules" is one rule, not two.
- A new pre-commit hook, `skill-size-check` (`scripts/skill-size-check.sh`), enforces the
  500-line/5,000-token `SKILL.md` ceiling, sibling to `skill-frontmatter`. Both halves of that
  ceiling are blocking gates, not just the line count: `MAX_LINES=500`, and `MAX_WORDS=2770` as a
  word-count proxy for the 5,000-token limit (calibrated to the densest prose this repo measured,
  1.81 tokens per word, so a worst-case `SKILL.md` at the ceiling still lands under 5,000 tokens —
  `wc -w` is not BPE tokenization). Either one exceeded fails the hook. Both are
  inclusive: a file at exactly 500 lines or exactly 2,770 words passes, and only one past a ceiling
  fails. `skill-audit/scripts/validate.sh` enforces the same pair on the same inclusive terms, so
  the audit and the commit hook cannot disagree about whether a given `SKILL.md` is over size.
- `styles/KyberforgeTrial/` and `.vale.trial.ini` were deliberately not created — noted here so a
  future reader doesn't wonder if a trial tier was forgotten.
- The styles-portability question — whether `styles/` and `.vale.ini` should move into
  `plugins/lint/` so the prefilter also works for repos that install `kyberforge@holocron` as an
  external plugin, rather than living at this repo's root — was deliberately deferred, not fixed,
  in this pass. This repo-root placement remains intentional: this ADR's "File scope stays the
  same" framing is specific to Kyberforge's own authoring conventions in this repo, not a generic
  `lint`-plugin feature. Portability is a known limitation, tracked for a separate future session,
  not silently forgotten.

**What this ADR's implementation pass did:** synced and trialed `write-good`/`alex` against the
existing SKILL.md/agent-file corpus, cherry-picked the one low-noise rule above into
`styles/Kyberforge`, wrote `scripts/skill-size-check.sh` and its pre-commit hook, fixed the
resulting corpus violations, and landed the rule changes and corpus fixes as one atomic commit —
matching the enforcement model described above (no partial or opt-in state), with every rule at
`level: error` so that model is real rather than nominal.