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Drift

drift binds markdown docs to code and lints for staleness.

Why this matters for agents

When you change code without updating the docs that describe it, those docs become stale. Stale docs get loaded as context in future sessions and produce wrong code based on wrong descriptions. This compounds — each session that trusts a stale doc makes things worse. drift makes the anchor explicit and enforceable so this feedback loop breaks.

Relink gate

drift link refuses to restamp a stale anchor without explicit review. When a target's signature has drifted, drift link prints both sides — the doc section (spec) and the current code — then exits 1.

This means you cannot blindly relink. You must review the doc prose and confirm it is still accurate. Use:

drift link docs/auth.md --doc-is-still-accurate

After you change code

Find which docs reference the files you touched:

drift refs src/auth/login.ts

Or check all docs at once:

drift check

If a doc is stale because of your change:

1. Run drift link <doc-path> — it will print the doc section and current code side by side, then refuse
2. Read both sides to understand what's out of sync
3. Update the doc's prose to reflect what you changed
4. Run drift link <doc-path> --doc-is-still-accurate — succeeds now that you've reviewed
5. Verify: drift check

Do not skip this. Leaving a doc stale is worse than leaving it unwritten.

After you change a doc

Refresh all anchors in the doc to snapshot current state:

drift link docs/my-doc.md

This updates provenance on all bindings in drift.lock for that doc, including inline @./ references.

When you create new code

If the new code is covered by an existing doc, add an anchor:

drift link docs/auth.md src/auth/new-handler.ts

If the new code deserves its own doc, write one and link it:

drift link docs/new-feature.md src/feature/index.ts
drift link docs/new-feature.md src/feature/types.ts#Config

When you delete or rename code

If a bound file is deleted or renamed, drift check will report it as STALE with "file not found". Remove the stale anchor:

drift unlink docs/auth.md src/auth/old-handler.ts

If you renamed the file, unlink the old path and link the new one:

drift unlink docs/auth.md src/auth/old-name.ts
drift link docs/auth.md src/auth/new-name.ts

Update the doc prose to reflect the rename.

When you refactor

Refactors that move code between files or rename symbols can break multiple docs at once. Run drift check after refactoring to find all affected docs, then update each one.

When drift check fails in CI

Someone changed bound code without updating docs. Read the lint output to see which docs are stale and why, update the doc prose, then drift link to refresh provenance.

Anchor syntax

Bindings in drift.lock:

docs/auth.md -> src/auth/login.ts sig:a1b2c3d4e5f6a7b8
docs/auth.md -> src/auth/provider.ts#AuthConfig sig:c3d4e5f6a7b8a1b2
docs/overview.md -> docs/auth.md#authentication sig:b3c4d5e6f7a8b9c0

Anchors can target code files, code symbols (file#Symbol), or doc headings (doc.md#heading-slug). Heading fragments use GitHub-style slugs (lowercase, hyphens).

drift link writes bindings to drift.lock with content signatures (sig:<hex>). Content signatures are AST fingerprints of the target, so staleness detection works without querying VCS history. This means drift link works on uncommitted files — no need to commit first.

When relinking a stale anchor, drift link refuses and prints both sides (doc section and current code) so you can review the change. Pass --doc-is-still-accurate to confirm the doc doesn't need updates.

drift lint also checks all markdown links ([text](path.md)) in drift-managed docs for existence — broken links are reported as BROKEN without needing a lockfile entry.

Cross-repo docs (origin)

Docs installed from other repos (like this skill) carry origin: on their bindings in drift.lock so drift check skips their anchors in consumer repos. If you're writing a doc that will be distributed to other repos, add origin to prevent false positives:

docs/skill.md -> src/main.ts sig:a1b2c3d4e5f6a7b8 origin:github:your-org/your-repo

Staleness

drift check reads bindings from drift.lock and exits 1 if any anchor is stale. Use drift check --changed <path> to scope checking to docs whose targets match a given path prefix — useful in CI when you know which files changed. For supported languages (TypeScript, Python, Rust, Go, Zig, Java), comparison is syntax-aware — formatting-only changes won’t trigger staleness. Stale reports include git blame-style context (who last touched the line of interest, which commit, subject) so you can see what changed.

For --format json, the payload is schema_version: drift.check.v1 (see the repo’s docs/check-json-schema.md). There, blame.date is the committer date in ISO 8601 strict form, not author date — use it when you need a stable time ordering after rebases. The summary includes verification_state (none | partial | full) describing how many docs were actually checked versus skipped (e.g. origin mismatch).

Reasons:

• changed after doc — file/symbol content differs from provenance snapshot
• file not found — bound file no longer exists
• symbol not found — bound symbol no longer exists in the file

drift lint is an alias for drift check.