wasm-mcp

Name: wasm-mcp
Author: xyzzylabs

by xyzzylabsversion 0.2.16i★ –iComputer or cloud

Registry nameio.github.xyzzylabs/wasm-mcp

Install

Overview

Description from the maker (original English)

Read-only MCP server for the WebAssembly spec: instructions, types, sections, search, proposals.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiVery new↓ 109/wk · ★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Computer or cloud
Transport: stdio, Streamable HTTP
Category: Search & AI memory

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on the maker’s server: what you ask it goes through their server.
The registry lists no key to fill in.

You need

Runs in the cloudNothing to install; it connects over the internet
npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

Open Settings → Connectors
Press Add custom connector
Paste the address below and press Add
If it asks you to sign in, sign in with the maker

https://mcp.xyzzylabs.ai/wasm/mcp

Or run it on your computer

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

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

Run this in your terminal

claude mcp add --transport http wasm https://mcp.xyzzylabs.ai/wasm/mcp

Or run it on your computer

claude mcp add wasm -- npx -y wasm-mcp

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "wasm": {
      "url": "https://mcp.xyzzylabs.ai/wasm/mcp"
    }
  }
}

Or run it on your computer

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

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

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "wasm": {
      "type": "http",
      "url": "https://mcp.xyzzylabs.ai/wasm/mcp"
    }
  }
}

Or run it on your computer

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "wasm": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "wasm-mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

ChatGPT connects only to servers on the internet:

Open ChatGPT on the web → Settings → Connectors (Apps)
Press Create or Add (some plans need Developer mode under Advanced first)
Paste the address below, give it a name and save
If it asks you to sign in, sign in with the maker

https://mcp.xyzzylabs.ai/wasm/mcp

Menu names can differ slightly by plan and over time.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

We have not read this server’s tool list yet; we check endpoints in rotation.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account xyzzylabs, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
… Not checked yet
Endpoint responds
Not checked yet; we check endpoints in rotation
… Not checked yet
Sign-in with OAuth
Not checked yet; we check endpoints in rotation
… Not checked yet
No hidden instructions in tool descriptions
Not checked yet; we read the tool list when we check the endpoint

Compared with others in Search & AI memoryi

More stars than 0% of the other 5718 servers in this category
Published to the registry more recently than 22% of the other 5718 servers in this category
Basic checks equal to or better than 100% of the other 5718 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is wasm-mcp safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

Either way works: install it on your computer or connect to the cloud version.

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.2.16) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Context7, Codebase Memory, Exa

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Context7

Feeds AI the latest docs for libraries and frameworks before it answers, so code it writes does not use outdated, removed functions.

by upstashWidely used↓ 972.7K/wk★ 64.2KUpdated 2 days ago

Computer or cloud

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Codebase Memory

Codebase knowledge graph for AI agents — 162 languages, sub-ms queries, 99% fewer tokens.

by DeusDataWidely used↓ 18K/wk★ 48.1KUpdated 22 days ago

Runs on your computer

Install

Exa

Connect AI agents to Exa for web search, content fetching, and multi-step research.

by exa-labsWidely used★ 5.2KUpdated 2 months ago

Runs in the cloud✓ exa.ai

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

wasm-mcp

Model Context Protocol server for the WebAssembly core specification. SHA-pinned, read-only, deterministic — safe to host as a public unauthenticated endpoint.

Not affiliated with, endorsed by, or sponsored by the W3C

WebAssembly Community Group or Working Group.

What it gives you

spec_version — the pinned upstream commit and package version.
instruction_get — opcode bytes, category, introducing version, stack type signature, validation + execution prose anchors / URLs, and trap conditions (traps + can_trap), by mnemonic (i32.add) or binary opcode (0x6a).
instruction_list — enumerate, filterable by category (numeric, vector, reference, parametric, variable, table, memory, control, ref, i31, struct, array, extern), introducing version, or prefix.
instruction_search — ranked free-text search across mnemonics, categories, and opcodes.
type_get — value types (number / vector / reference) and type forms (functype, limits, memtype, …) with defining prose.
section_get — one spec clause by id / anchor (structure, validation, execution, binary, text), with prose, cross-references, SpecTec formal-rule references, and the rendered URL.
section_list — navigate the clause tree by area or anchor prefix.
spec_search — full-text search across anchors, titles, and prose.
proposal_list — WebAssembly proposals and their phases (from the pinned WebAssembly/proposals repo), filterable by status, phase, champion, or affected spec.

section_get, section_list, and spec_search take a spec argument covering all three specs in the WebAssembly/spec repo: core (default), js-api (the JavaScript embedding API), and web-api (Web-platform integration). The instruction and type tools are core-only.

Contract

Every tool is:

Read-only. No state mutation, no writes outside an optional local cache.
Deterministic. Same input → same output, over the pinned spec commit recorded in vendor/PINNED.txt.
No execution. Never compiles, validates-by-running, instantiates, or runs any WebAssembly or arbitrary code. Validation and reduction rules are returned as data.
No auth, no secrets, no PII. Usable anonymously.
No network at request time. All spec data is fetched and indexed at build time and baked into the package.

Install (stdio, local)

npx wasm-mcp

Wire it into any MCP client by adding the server to its config (the launch command is the same everywhere; only the config file differs):

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

Hosted Worker

The Cloudflare Worker in worker/ exposes the same tool surface as the stdio package over streamable HTTP at a single unauthenticated endpoint, rate-limited per source IP (30 req / 60 s):

https://mcp.xyzzylabs.ai/wasm/mcp

GET /wasm/health reports status and the pinned SHAs; GET /wasm/privacy states the anonymous, no-storage posture. All spec data is bundled into the Worker, so it does pure in-memory lookups — no storage, no network at request time.

Releases & data refresh

The pinned commits live in vendor/PINNED.txt and are reported by spec_version. A scheduled GitHub Actions workflow (refresh.yml) SHA-diffs the upstream repos daily; when a pin moves it re-pins, bumps the patch version, and tags a release, which publishes the npm package (release.yml) and redeploys the Worker (deploy-worker.yml).

Maintainers:

npm publish uses Trusted Publishing (OIDC) — no NPM_TOKEN. Configure it once on npmjs.com (wasm-mcp → Settings → Trusted Publisher → GitHub Actions: org xyzzylabs, repo wasm-mcp, workflow release.yml).
Worker deploy needs CLOUDFLARE_API_TOKEN + CLOUDFLARE_ACCOUNT_ID, stored as environment secrets on the cloudflare GitHub Environment (not repo-wide) with a main + v* deployment rule — see Securing the deploy credentials.
For the refresh workflow's tag push to trigger release + deploy, add a WORKFLOW_PAT PAT (contents: write + workflows) — without it, refresh still re-pins and tags, but you run release / deploy manually. (Same secret name tc39-mcp uses, so one PAT — or an xyzzylabs org secret — can serve both repos.)

License

MIT — see LICENSE.

wasm-mcp

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Or run it on your computer

Or run it on your computer

Or run it on your computer

Or run it on your computer

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Search & AI memoryi

Common questions

Alternatives

Context7

Codebase Memory

Exa

README from the maker

wasm-mcp

What it gives you

Contract

Install (stdio, local)

Hosted Worker

Releases & data refresh

License