tc39-mcp

Name: tc39-mcp
Author: xyzzylabs

MCP serverMCP

Independent MCP server for the TC39 specs (ECMA-262 + ECMA-402): clauses, search, diffs, history.

by xyzzylabsrepository ↗homepage ↗v0.6.4MIT

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Evidence

Everything here was measured by our prober or read from a registry. Nothing is self-reported.

30-day availability109/109 checks ok

when	check	result	http	latency	detail
2 h ago	mcp initialize	ok	200	148 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
9 h ago	mcp initialize	ok	200	120 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
15 h ago	mcp initialize	ok	200	153 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
22 h ago	mcp initialize	ok	200	62 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
28 h ago	mcp initialize	ok	200	70 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
34 h ago	mcp initialize	ok	200	73 ms	server tc39-mcp 0.6.5 · protocol 2024-11-05 · 17 tools
2 d ago	mcp initialize	ok	200	91 ms	server tc39-mcp 0.6.4 · protocol 2024-11-05 · 17 tools
2 d ago	mcp initialize	ok	200	63 ms	server tc39-mcp 0.6.4 · protocol 2024-11-05 · 17 tools
2 d ago	mcp initialize	ok	200	86 ms	server tc39-mcp 0.6.4 · protocol 2024-11-05 · 17 tools
3 d ago	mcp initialize	ok	200	81 ms	server tc39-mcp 0.6.3 · protocol 2024-11-05 · 17 tools

Tools observed via MCP handshake

spec.about — Self-description of this MCP server: package name + version, per-snapshot pin metadata (sha, fetched_at, biblio_commit, clause_count) for every supported (spec,
clause.get — Fetch a parsed TC39 clause as structured JSON. `spec` selects '262' (default) or '402'. `edition` defaults to 'latest'. `at: '<sha>'` pins to a historical main
clause.list — List parsed spec clauses with optional filters (kind, section prefix, has_algorithm). `spec` selects '262' or '402'. `at: '<sha>'` queries a historical main sna
spec.search — Search the parsed spec by clause id / aoid / title (+ step text with `search_steps`). Aoid-exact ranks first. `at: '<sha>'` searches a historical main snapshot.
proposal.list — List TC39 proposals from the static index (tc39/proposals). Filter by spec ('262'|'402'), stage ('0'|'1'|'2'|'2.7'|'3'|'finished'|'inactive'|'active'), champion
proposal.get — Fetch one TC39 proposal by slug (exact) or name (case-insensitive).
spec.grammar — Query grammar productions captured from the spec's `<emu-grammar>` blocks. `{ nonterminal }` returns every production for that non-terminal (exact match); `{ co
spec.tables — List or fetch parsed `<emu-table>` content. `{ id }` returns exactly that table (full columns + rows); otherwise list table summaries, optionally narrowed by a
spec.sdo_index — Index Syntax-Directed Operations by the grammar production they're defined on. `by: 'production'` (default) groups SDOs under each production; `by: 'sdo'` group
clause.outline — Return the section tree (table of contents) for a parsed (spec, edition). `depth` caps how deep the tree descends (1 = top-level only); `under` limits the tree
spec.global_search — Run spec.search across both ECMA-262 and ECMA-402 in one call and interleave hits by score. Each hit is tagged with the spec it came from. Use it when you don't
spec.snapshots — List the live (spec, edition, sha, fetched_at) snapshots the hosted Worker is serving from R2. Filter by `spec` ('262'|'402') or `edition` (e.g. 'main', 'es2026
spec.symbol_resolve — Resolve spec notation like `[[Prototype]]` (internal slot), `%Object.prototype%` (well-known intrinsic), or `~number~` (sigil enum): return clauses that mention
spec.well_known_intrinsics — Enumerate the well-known intrinsics in a spec with their probable defining clauses. Driven from the canonical §6.1.7.4 WKI table when present (ECMA-262), else a
spec.diff — Clause-level diff of one clause across two editions of a spec. Reports identical / modified / added / removed plus a field-level breakdown (title, signature, st
spec.crossrefs — 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 d
test262.search — Search the tc39/test262 conformance suite from its indexed front-matter. `query` AND-matches whitespace tokens (case-insensitive) across each test's description

Declared by sources

What the publisher says

Attributed to the source that supplied each field. Treated as claims, not facts.

No long description beyond the summary.

ecmascriptecma262ecma402tc39intljavascript-specspecificationlanguage-specmcpmodel-context-protocol

kind Official MCP Registry

name Official MCP Registry

license npm registry

repoUrl Official MCP Registry

summary Official MCP Registry

version Official MCP Registry

description Official MCP Registry

homepageUrl Official MCP Registry

publisherName Official MCP Registry

Provenance

Where this record came from

Every source is kept verbatim. Field changes are logged as events.

npm registrytc39-mcp

first seen 1 mo ago · fetched 17 d agoopen ↗

Official MCP Registryio.github.xyzzylabs/tc39-mcp

first seen 1 mo ago · fetched 34 h agoopen ↗

Field history (12 recent events)

34 h ago · declared · version → "0.6.4"
1 mo ago · declared · version → "0.6.3"
1 mo ago · observed · packageFacts → {"name":"tc39-mcp","registry":"npm","publishedAt":"2026-09-08T12:49:51.269Z","latestVersion":"0.6.3","weeklyDownloads":1
1 mo ago · declared · homepageUrl → "https://mcp.xyzzylabs.ai/tc39"
1 mo ago · declared · repoUrl → "https://github.com/xyzzylabs/tc39-mcp"
1 mo ago · declared · summary → "Independent MCP server for the TC39 specs (ECMA-262 + ECMA-402): clauses, search, diffs, history."
1 mo ago · declared · description → "Independent MCP server for the TC39 specs (ECMA-262 + ECMA-402): clauses, search, diffs, history."
1 mo ago · declared · repoUrl → null
1 mo ago · declared · summary → "Unofficial MCP server for the TC39 specs (ECMA-262 + ECMA-402) — SHA-pinned clauses, AOID-aware search, in+out cross-re
1 mo ago · observed · packageFacts → {"name":"tc39-mcp","registry":"npm","publishedAt":"2026-08-07T00:57:54.805Z","latestVersion":"0.6.2","weeklyDownloads":9
1 mo ago · declared · description → "Unofficial MCP server for the TC39 specs (ECMA-262 + ECMA-402) — SHA-pinned clauses, AOID-aware search, in+out cross-re
1 mo ago · declared · publisherName → "xyzzylabs"

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