Doc Sync

doc-sync

Documentation rots because it is written once and edited by hand. This skill keeps it true to the repo with a simple rule: automate the snapshot, human-curate the narrative. Those are two different kinds of document and they must be treated differently — collapsing them is how doc-sync tools either go stale or quietly mangle carefully-written prose.

The two kinds of doc

• Snapshot docs — a STATUS.md, PROGRESS.md, or "current state" section. These answer "what exists right now?". They decay every working session and are safe to regenerate from facts. doc-sync rewrites these.
• Curated docs — a vision / "why" doc, an architecture / "how" doc, a README narrative. These are deliberate prose that change rarely. doc-sync never rewrites them unprompted — it only flags discrepancies and proposes edits for the user to approve. Auto-editing prose is how you degrade the best writing in the repo.

If you are unsure which bucket a doc is in, ask. When in doubt, treat it as curated (flag-only) — the cost of a missed flag is lower than the cost of garbling prose.

How the user configures it

Look for configuration in this order; if none exists, ask the user which docs are snapshot vs curated and offer to write a .doc-sync.json.

1. .doc-sync.json at the repo root:

   {
     "snapshot": ["STATUS.md"],
     "curated": ["docs/VISION.md", "ARCHITECTURE.md"],
     "facts": {
       "components": "grep -nE 'id=\"' src/registry.ts",
       "phases": "STATUS.md"
     }
   }
   

   facts.components is any read-only command that lists the project's registered units (compositions, routes, plugins, services — whatever this project enumerates). Omit it if the project has no such registry.
2. Inline markers — a doc containing <!-- doc-sync: snapshot --> near the top is treated as a snapshot; <!-- doc-sync: curated --> as curated.
3. Defaults — STATUS.md / PROGRESS.md are snapshot; VISION*, ARCHITECTURE*, DESIGN*, PRD*, SPEC*, README* are curated. A PRD or spec is a special case of curated: it's a proposal that turns true as the project gets built, so flag when its stated status (e.g. "not started", a build-order step, a Status: line) no longer matches what's shipped — and reconcile it with the snapshot doc — but propose the edit rather than rewriting the spec.

Workflow

1. Gather live facts (read-only only)

Never mutate the repo while gathering. Collect whatever the project actually has:

• Registered units — run the project's facts.components command, or infer it (e.g. grep the route/registry/manifest file). Count and name them.
• Branch + merge state — git branch, git branch --merged <default>, git status -sb, git log --oneline -15. Distinguish merged vs open branches.
• Build / phase state — read the snapshot doc's own phase list and check each claim against reality (does the code/dir it references exist?).
• Optional sanity — a typecheck / lint / test command if the project has a fast one, to mark "green" honestly.

2. Regenerate the snapshot doc

Rewrite the snapshot doc to match the facts. Update tables, the branch/backlog section, phase ticks, and the "Last updated" date to today. Preserve the doc's existing structure and voice — you are refreshing values, not redesigning the file.

3. Flag drift in curated docs (do not rewrite)

Compare each curated doc against the facts — e.g. does an architecture doc's component table still match what's registered? Do the phases agree? List the specific discrepancies and proposed edits, then ask before applying any. Apply only what the user approves.

4. Refresh exported twins

If a doc has an exported version generated from it — a PDF, an HTML page, a slide deck — a stale export is as misleading as a stale doc. After the source changes, regenerate the twin so the two match. Use the project's own build command if it has one (e.g. a docs/md2pdf.py, a make docs, a pandoc invocation); if it doesn't, flag the exports that are now out of date rather than guessing at a tool. Don't regenerate a twin for the snapshot doc unless the project clearly publishes one — snapshots churn, and a PDF of a thing that changes every session is just noise.

5. Land the changes

Commit the snapshot refresh, any approved curated edits, and the regenerated exports. Follow the repo's own workflow — match its branch/PR conventions; don't push if the project protects its default branch and the user hasn't asked.

The honesty bar (non-negotiable)

The whole point is a doc you can trust. Overclaiming destroys that faster than staleness does. Hold these distinctions in every edit, and prefer the weaker verb when unsure:

Examples:

• built ≠ deployed — code exists vs it's live for users.
• committed ≠ merged — on a branch vs on the default branch.
• wired ≠ working ≠ shipped — connected vs verified vs released.
• passing locally ≠ passing in CI.
• designed ≠ implemented.

If a claim can't be backed by a fact you gathered, soften it or drop it. A status doc that admits "not started" where true is worth more than one that rounds up.

Why it's split this way

A snapshot doc is a function of the repo state — regenerating it is correct and cheap. A vision or architecture doc is authored intent — a model rewriting it on every sync would slowly flatten its meaning. Keeping the human in the loop for prose, and only for prose, is what makes this safe to run often.