Get started in 5 minutes

wasm-mcp is a read-only Model Context Protocol server over the WebAssembly specification. It exposes the instruction set, value/function types, spec sections, full-text search, and the proposal phase list as structured tools, so an AI agent can cite the spec precisely instead of guessing.

Option A — local (stdio)

No install needed; npx fetches and runs it.

Claude Code / Claude Desktop

Add to your project's .mcp.json (or the Claude Desktop config):

{
  "mcpServers": {
    "wasm": { "command": "npx", "args": ["wasm-mcp"] }
  }
}

Restart the client; the wasm server's 9 tools appear in the tool picker.

Any MCP client

npx wasm-mcp        # speaks MCP over stdio

Option B — hosted (HTTP)

Point any streamable-HTTP MCP client at the hosted Worker — nothing to install:

https://wasm-mcp.chicoxyzzy.workers.dev/mcp

It's anonymous (no auth) and IP-rate-limited. GET /health reports the pinned SHAs; see Deployment to host your own.

First calls

Once connected, try:

• spec_version — what commit is this data pinned to?
• instruction_get { "mnemonic": "i32.add" } — opcode, signature, anchors.
• instruction_get { "opcode": "0x0d" } — reverse-lookup by opcode.
• instruction_list { "category": "vec", "introduced_in": "3.0" } — what relaxed-SIMD instructions did Wasm 3.0 add?
• type_get { "name": "funcref" } — classification + sibling types.
• spec_search { "query": "trap" } — find clauses by text.
• section_get { "id": "memories", "spec": "js-api" } — read a JavaScript-embedding clause (the spec arg also takes web-api).
• proposal_list { "status": "finished", "affects": "core" } — what landed in the core spec.

The full surface, with every input field and more examples, is on the Tool reference.

What you can rely on

• Read-only & deterministic — same input, same output, over a pinned spec commit. No tool mutates anything or runs any Wasm.
• No network at request time — all data is baked in at build time.
• Honest provenance — every section/instruction answer carries the stable anchor and the rendered spec URL; spec_version reports the exact pinned commits.