AGENTS.md promises that docs and code stay strictly in sync, but the promise was verified by eyeball. Review caught drift twice — a cookbook example contradicting the type policy, and a README citing the wrong `registerAdapter` call. Out-of-sync docs are worse than no docs, and this codebase is built primarily by agents that follow gates far more reliably than prose (ADR 0007). Three classes are mechanically checkable: code blocks that no longer compile, the event-taxonomy table that duplicates the `interface Events` declarations, and hard-wrapped Markdown prose that violates the repo's one-line-per-paragraph convention.
1.**`doc-typecheck`** extracts every fenced ` ```ts ` block from `README.md`, `docs/**`, and `packages/*/README.md`, writes them to a temp project, and compiles with `tsc --noEmit`. The temp tsconfig copies only resolution-relevant options and the workspace `paths` map from `tsconfig.typecheck.json` (vendor → built `lib`, harness → `src`) — resolving vendor to `lib` is essential, or tsc type-checks raw vendor source and floods the run. A block that is a deliberate sketch opts out with an explicit ` ```ts ignore-check ` info string; the script reports the opt-out ratio and fails if it exceeds half, so the escape hatch can't quietly become the norm.
2.**`verify-event-taxonomy`** extracts the event names from the `interface Events` blocks across `packages/*/src` and from the taxonomy table in `docs/architecture.md`, and asserts the two sets match exactly. Verify, don't generate: the table keeps its hand-written Mode/Purpose columns; only the set of names is checked. (Landing this surfaced three events the table had been missing — `tools/change`, `llm/adapter-change`, `system-prompt/change`.)
3.**`verify-md-wrap`** parses each in-scope Markdown file (`README.md`, `docs/**`, `packages/*/README.md`, plus `AGENTS.md` / `packages/AGENTS.md`) with `mdast-util-from-markdown` + GFM and fails on any `paragraph` node spanning more than one source line, enforcing the AGENTS.md "Markdown is not hard-wrapped" convention. Same verify-don't-generate principle: it reports hard-wraps and never rewrites, so it adds no formatting churn.
All three run via a shared `doc-sync` package.json script that the lefthook pre-push hook and CI both invoke (ADR 0007: hooks and CI call the same scripts, so the gate fires locally before a push — not only after it). They run after `pnpm run typecheck` (which emits the vendor `lib/` that doc-typecheck resolves against). API-extractor golden reports (RFC 006 part 3) were deliberately **deferred** — low value for an internal monorepo where reviewers already see the source diff, and a heavy, finicky dependency.
- Doc drift in the checkable classes now fails the pre-push hook and CI instead of waiting for a reviewer to notice. This is an instance of ADR 0007's "mechanical gates over prose."
- Making doc snippets compile costs a few stub imports/`declare`s; the `ignore-check` ratio must stay low or the gate is theater (the ratio guard enforces this).
- The taxonomy check is name-only — a wrong Mode or Purpose column still needs human review. Generating the table from source was considered and rejected as more machinery than the problem warrants.
- API reports remain available to revisit if the packages are ever published externally.
