tc39-mcp

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.

{
  "type": "object",
  "properties": {},
  "additionalProperties": false
}

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 snapshot (only valid for edition='main'); omit to query the live snapshot.

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "at": {
      "type": "string",
      "description": "Optional historical SHA pin (hex, 4-40 chars). Only valid when edition='main'; released editions have no per-SHA history to address."
    }
  },
  "required": [
    "id"
  ]
}

List parsed spec clauses with optional filters (kind, section prefix, has_algorithm). `spec` selects '262' or '402'. `at: '<sha>'` queries a historical main snapshot.

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "at": {
      "type": "string"
    },
    "kind": {
      "type": "string"
    },
    "section": {
      "type": "string"
    },
    "has_algorithm": {
      "type": "boolean"
    },
    "limit": {
      "type": "number"
    }
  }
}

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.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "at": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    },
    "search_steps": {
      "type": "boolean"
    }
  },
  "required": [
    "query"
  ]
}

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 (substring), or contains (name/slug substring).

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "stage": {
      "type": "string"
    },
    "champion": {
      "type": "string"
    },
    "contains": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}

Fetch one TC39 proposal by slug (exact) or name (case-insensitive).

{
  "type": "object",
  "properties": {
    "name": {
      "type": "string"
    }
  },
  "required": [
    "name"
  ]
}

Query grammar productions captured from the spec's `<emu-grammar>` blocks. `{ nonterminal }` returns every production for that non-terminal (exact match); `{ contains }` filters by RHS / name substring; neither lists all non-terminals + their production counts. `include_sdo` folds in SDO-attached productions (off by default).

{
  "type": "object",
  "properties": {
    "nonterminal": {
      "type": "string"
    },
    "contains": {
      "type": "string"
    },
    "include_sdo": {
      "type": "boolean"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}

List or fetch parsed `<emu-table>` content. `{ id }` returns exactly that table (full columns + rows); otherwise list table summaries, optionally narrowed by a `filter` substring over the caption or id.

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string"
    },
    "filter": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}

Index Syntax-Directed Operations by the grammar production they're defined on. `by: 'production'` (default) groups SDOs under each production; `by: 'sdo'` groups productions under each SDO title. `filter` narrows to keys containing a substring (case-insensitive).

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "by": {
      "type": "string",
      "enum": [
        "production",
        "sdo"
      ]
    },
    "filter": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}

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 to descendants of one clause id.

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "depth": {
      "type": "number"
    },
    "under": {
      "type": "string"
    }
  }
}

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 know which spec defines a symbol. `search_steps` also matches algorithm step text.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string"
    },
    "search_steps": {
      "type": "boolean"
    },
    "limit": {
      "type": "number"
    }
  },
  "required": [
    "query"
  ]
}

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'). Historical SHA-pinned copies are reachable via `at:` on clause.get / spec.search but aren't enumerated here.

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    }
  }
}

Resolve spec notation like `[[Prototype]]` (internal slot), `%Object.prototype%` (well-known intrinsic), or `~number~` (sigil enum): return clauses that mention or define it, ranked by occurrence with a bump for definition-y sections.

{
  "type": "object",
  "properties": {
    "notation": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  },
  "required": [
    "notation"
  ]
}

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 `%X%` prose scan (e.g. ECMA-402). `filter` narrows by bare-name substring.

{
  "type": "object",
  "properties": {
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "filter": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}

Clause-level diff of one clause across two editions of a spec. Reports identical / modified / added / removed plus a field-level breakdown (title, signature, step count, reworded step indices, notes, crossrefs). `from` defaults to the latest stable release, `to` to main.

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "from": {
      "type": "string"
    },
    "to": {
      "type": "string"
    }
  },
  "required": [
    "id"
  ]
}

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). The reverse index is AOID-densified from step text. `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).

{
  "type": "object",
  "properties": {
    "id": {
      "type": "string"
    },
    "spec": {
      "type": "string",
      "enum": [
        "262",
        "402"
      ]
    },
    "edition": {
      "type": "string"
    },
    "direction": {
      "type": "string",
      "enum": [
        "in",
        "out",
        "both"
      ]
    },
    "include_cross_spec": {
      "type": "boolean"
    },
    "limit": {
      "type": "number"
    }
  },
  "required": [
    "id"
  ]
}

Search the tc39/test262 conformance suite from its indexed front-matter. `query` AND-matches whitespace tokens (case-insensitive) across each test's description + path; `esid` prefix-matches the front-matter esid. Returns ranked hits (path, GitHub url at the indexed SHA, esid, description, features, flags), capped at `limit` (default 20). Supply at least one of `query` / `esid`.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string"
    },
    "esid": {
      "type": "string"
    },
    "limit": {
      "type": "number"
    }
  }
}