CHEAP — start here. Full-text search over the local SQLite index of the vault; it never downloads the whole vault. Matches title, summary, tags and body, folds diacritics, expands synonyms and accepts "quoted phrases". A bare commit sha looks up the notes that mention it. Excludes the archive and superseded notes unless you ask for them, and reports how many it hid.

MODERATE — one round trip to storage. Returns the note with an etag: first line; pass that etag back to write_file to refuse a write over someone else's change. Search first.

WRITE — validates the frontmatter against the vault schema and refuses the write if it does not hold. Stamps updated with today and fills date when missing. Pass expected_etag from read_file to make the write conditional.

WRITE — appends to a note and bumps updated. Creates the note when it is missing.

WRITE — moves or renames a note. Use close to archive finished work.

WRITE — deletes a note for good. Prefer close, which keeps it.

CHEAP — paths only, no metadata and no bodies. search answers context questions better.

WRITE — finishes a note: sets status complete (or superseded with superseded_by when merged_into is given) and moves it into the archive. Run it in the same pass as the last commit of the work; a note left open is what makes the vault drift.

WRITE — appends one dated line to the repo log, with the commits it produced. Run once at the end of a session per repo. Creates the log note when it is missing.

CHEAP — the session-start call. Returns the system notes covering the code at path, the open tasks for it, the reference notes and the tail of the repo log, in one answer. Use it before searching blind.

MODERATE — reads every note to report drift: broken frontmatter, missing required fields, missing area, unresolved wikilinks, orphans, stale open tasks, archived notes still marked active, duplicate stems and superseded targets that do not exist.