The tc39-mcp MCP server,
connected in one click.
Independent MCP server for the TC39 specs (ECMA-262 + ECMA-402): clauses, search, diffs, history. Connect the official tc39-mcp MCP server to Claude, ChatGPT, or Cursor through gate — one gateway URL, no config files, security-checked.
Free to start · No credit card · No hosting needed
Add tc39-mcp to your AI in one minute
Pick your client. Copy, paste, done — or let gate handle sign-ins and policies for you.
claude mcp add --transport http tc39-mcp https://mcp.xyzzylabs.ai/tc39/mcpRun in your terminal, then restart Claude Code.
tc39-mcp · https://mcp.xyzzylabs.ai/tc39/mcp
What your AI can do with tc39-mcp
Real prompts you can type the moment it's connected — no setup, no docs to read.
“Use “spec.about”: Self-description of this MCP server: package name + version, per-snapshot pin metadata (sha, fetched_at, biblio_commit, clause_count) for ev.”
“Use “clause.get”: Fetch a parsed TC39 clause as structured JSON. `spec` selects '262' (default) or '402'. `edition` defaults to 'latest'. `at: '<sha>'` pins t.”
“Use “clause.list”: List parsed spec clauses with optional filters (kind, section prefix, has_algorithm). `spec` selects '262' or '402'. `at: '<sha>'` queries a.”
“Use “spec.search”: Search the parsed spec by clause id / aoid / title (+ step text with `search_steps`). Aoid-exact ranks first. `at: '<sha>'` searches a histo.”
How secure is the tc39-mcp MCP server?
Every server in the gate directory has to pass the same four checks before your AI can touch it. Here's how tc39-mcp holds up.
Security grade A
gate scanned 17 tools on Oct 7, 2026 for prompt injection and risky tool definitions — nothing to flag.
Official endpoint
Operated by tc39-mcp (xyzzylabs.ai) at its documented MCP endpoint — not a third-party mirror or community re-host.
No sign-in needed
This server only exposes public data — no account and no credentials are involved when you connect.
Scanned before it goes live
gate checks every tool for prompt injection, hidden instructions, data-exfiltration hints, and over-broad permissions before the server is available through your gateway.
Watched for drift
If tc39-mcp adds or changes tools later, gate re-scans and alerts you — before your AI acts on the change.
Connected in three steps
Connect your gate
Add one gateway URL to Claude, ChatGPT, or any MCP client. One-time setup, about two minutes.
Pick tc39-mcp
Choose tc39-mcp in the gate directory. No sign-in needed.
Use it anywhere
tc39-mcp's tools are live in every AI client you've connected — with rules and logging built in.
Free to start · No credit card · No hosting needed
The actual tools tc39-mcp exposes
Fetched live from the official endpoint and re-checked daily by gate — not marketing copy.
spec.about — Self-description of this MCP server: package name + version, per-snapshot pin metadata (sha, fetched_at, biblio_commit, clause_count) for ev
clause.get — Fetch a parsed TC39 clause as structured JSON. `spec` selects '262' (default) or '402'. `edition` defaults to 'latest'. `at: '<sha>'` pins t
clause.list — List parsed spec clauses with optional filters (kind, section prefix, has_algorithm). `spec` selects '262' or '402'. `at: '<sha>'` queries a
spec.search — Search the parsed spec by clause id / aoid / title (+ step text with `search_steps`). Aoid-exact ranks first. `at: '<sha>'` searches a histo
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'
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
spec.tables — List or fetch parsed `<emu-table>` content. `{ id }` returns exactly that table (full columns + rows); otherwise list table summaries, optio
+ 9 more tools once connected
Who runs the tc39-mcp MCP server?
The tc39-mcp MCP server at a glance
https://mcp.xyzzylabs.ai/tc39/mcpQuestions, answered
Is there an official tc39-mcp MCP server?
Yes — tc39-mcp operates its own remote MCP server at mcp.xyzzylabs.ai. gate connects you to that official endpoint and adds security scanning, per-tool access rules, and an activity log on top.
How do I connect tc39-mcp to Claude or ChatGPT?
Add gate's gateway URL to your AI client once, then pick tc39-mcp in the directory. No account or sign-in is needed. From then on, tc39-mcp's tools are available in every client you've connected to gate.
Do I need to host anything?
No. tc39-mcp runs the server, and gate is fully managed. You just connect one URL — there's nothing to install, deploy, or maintain.
Is the tc39-mcp MCP server safe to connect?
It's the vendor's official endpoint, and gate scans its tools for prompt injection and hidden instructions before it goes live, re-checks it whenever it changes, and lets you allow, block, or require approval for every single tool.
Is it free?
Yes — you can get started with gate for free and connect tc39-mcp in minutes. No credit card required.
Connect more than just tc39-mcp
Every server below works through the same gateway URL — connect once, add tools anytime.
Squarespace DomainsDesignView →Set up tc39-mcp in: Claude · Claude Code · ChatGPT · Cursor · VS Code