TC39 Specs (ECMA-262 + ECMA-402)

Fetch a parsed TC39 clause as structured JSON: metadata, signature, algorithm steps, notes, cross-refs, and outward citations to external specs (Unicode, IETF, WHATWG). spec selects '262' (default) or '402'. edition defaults to latest (current stable release on both specs — es2026 today).

List parsed spec clauses with optional filters (kind, section prefix, has_algorithm). Returns lightweight rows {id, aoid, title, number, kind, algorithms}; follow up with clause.get for detail. spec selects '262' or '402'.

Return the section tree (table of contents) for a parsed (spec, edition). depth caps tree depth (1 = top-level only). under anchors at a specific clause id so you get just its descendants. Each node carries { id, number, title, kind, children }.

Fetch one TC39 proposal by slug (exact) or name (case-insensitive). Returns { slug, name, stage, authors, champions, url, test262_flag, source_file }. Slug is canonical — use what proposal.list returns directly.

List TC39 proposals from a parsed proposals index sourced via the loader chain (local cache → hosted Worker → bundled fallback); the index is fetched on first use and cached locally. Filter by stage ('0'|'1'|'2'|'2.7'|'3'|'finished'|'inactive'|'active'), champion (substring), or contains (name/slug substring). Returns lightweight rows; follow up with proposal.get. No auth, no subprocess.

Return self-description of this MCP server: package name + version, per-snapshot pin metadata (sha, fetched_at, biblio_commit, clause_count) for every supported (spec, edition), plus test262 + proposals index headers when present. Lets callers verify freshness and reproducibility without loading the parses themselves.

For a clause id, return its outgoing references (clauses it cites) and/or incoming references (clauses that cite it — the back-reference index the parse alone doesn't expose). Direction: 'in' | 'out' | 'both' (default). Outgoing also carries an external category: the clause's citations to external specs (Unicode, IETF, WHATWG) as resolvable URLs. Set include_cross_spec: true to also resolve outgoing references from ECMA-262 → ECMA-402 (or vice versa).

Clause-level diff across any two editions of one spec. Defaults: from='latest', to='main' (working draft). Reports status (identical / modified / added / removed / missing-from-both) plus a field-level diff: title, signature, step count, per-step reworded indices, notes, crossrefs. spec selects '262' or '402'.

Run spec.search across both ECMA-262 and ECMA-402 in one call and interleave results by score. Each hit is tagged with the spec it came from. Useful when you don't know which spec defines the symbol (e.g. Canonicalize is 262, CanonicalizeLocaleList is 402).

Query standalone <emu-grammar> productions from the spec's lexical / syntactic grammar (§11-15 in 262). Three modes: { nonterminal: 'X' } returns every production for X; { contains: 'Y' } returns productions whose RHS or non-terminal name contains Y; neither returns a list of all non-terminals with their production counts. Set include_sdo:true to also surface SDO-attached grammar headers.

Recent commits in the vendored spec checkout that touched a clause's id="..." token. Uses git pickaxe (-S) so it catches clause creation, deletion, and edits to the opening tag reliably; interior-text-only edits won't show. Returns SHA, date, author, subject per commit. spec selects '262' or '402'.

Index Syntax-Directed Operations by the grammar production they handle. SDOs are abstract operations (Evaluation, BoundNames, etc.) with one <emu-alg> per production. Default by='production' returns { [production]: [{ sdo, id, title }] }; by='sdo' returns { [sdo title]: [productions] }. filter substring-narrows keys; spec selects '262' or '402'.

Search the parsed spec by clause id / aoid / title (and step text when search_steps is true). Returns lightweight hits ranked by match quality — the entry point when you don't know the exact clause id. spec selects '262' or '402'. Follow up with clause.get.

List every (spec, edition, sha, fetched_at) snapshot this server has parsed. Use to discover what historical SHAs you can query via at: "<sha>", or to verify reproducibility across server versions. Optional spec / edition filters.

Resolve spec notation like [[Prototype]] (internal slot), %Object.prototype% (well-known intrinsic), or ~number~ (sigil enum) to the clauses that mention or define it. Hits ranked by occurrence count + section-prefix bumps for the canonical definition location. spec selects '262' or '402'.

List or fetch parsed <emu-table> content. Pass id to get one table with full columns + rows; omit id to list tables (lightweight summaries) optionally filtered by caption/id substring. Authoritative source for the well-known intrinsics table (id='table-well-known-intrinsic-objects'), well-known symbols, completion record fields, etc. spec selects '262' or '402'.

Enumerate the well-known intrinsics (%X% notations) used in the spec, with each one's probable defining clause (chosen by a title-substring heuristic — see matched_on per hit). For the canonical 262 well-known intrinsics table, read clause.get { id: 'sec-well-known-intrinsic-objects' } directly.

Fetch one test's source + parsed front-matter by path within the vendored tc39/test262 checkout. Pairs with test262.search — the paths it returns plug in here directly. Returns { source, front_matter, test262_sha, url } or { hint } if the path can't be resolved.

Search tc39/test262 for tests matching a free-text query and/or an esid (clause id, prefix-matched). test262 covers both ECMA-262 and ECMA-402. Served from a parsed test262 index sourced via the loader chain (local cache → hosted Worker → bundled fallback); the index is fetched on first use and cached locally. If no layer can produce the index the result is empty + a hint explaining the one-time local build. No auth, no subprocess.