MCP.Market

wasm-mcp server

online · 100% uptime
by xyzzylabs·io.github.xyzzylabs/wasm-mcp·v0.2.16·2 stars
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Read-only MCP server for the WebAssembly spec: instructions, types, sections, search, proposals.

A92/100grade A
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Safety scan
A92/100

full report

Adoption
Growing

2 stars

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wasm-mcp tools (9)

write = sends, deletes, buys or posts
  • instruction_getFree

    Fetch one WebAssembly instruction by mnemonic (`i32.add`) or binary opcode (`0x6a`, multi-byte `0xfd 0x89 0x02`): opcode bytes, category, introducing version, stack type signature, validation/execution anchors + URLs, and `traps` (runtime trap conditions with canonical names; empty + `can_trap:false` when it never traps).

  • instruction_listFree

    Enumerate WebAssembly instructions, filterable by `category`, `introduced_in` (1.0|2.0|3.0), mnemonic `prefix`, and `can_trap` (only trapping / only non-trapping). Rows (incl. `can_trap`) sorted by opcode.

  • instruction_searchFree

    Ranked free-text search across instruction mnemonics, categories, and opcode hex. Returns hits with a `matched_on` field.

  • proposal_listFree

    List WebAssembly proposals + phases. Filter by `status` (phase-0…phase-5, finished, inactive), `phase` (0–5), `champion`, `affects` (core|js-api|web-api), or `contains`.

  • section_getFree

    Fetch one spec clause by id or anchor across `core` / `js-api` / `web-api` (`syntax-numtype`, `valid-unreachable`, `modules`, `streaming-modules`, …): title, prose, cross-references, SpecTec formal refs, and rendered URL.

  • section_listFree

    Navigate the clause tree of a spec (`core` / `js-api` / `web-api`), filterable by source `path` (`syntax`, `valid`, `exec`, `binary`, `text`, `appendix`), `anchor_prefix`, `titled_only`, and `max_level`.

  • spec_searchFree

    Full-text search across clause anchors, titles, and prose of a spec (`core` / `js-api` / `web-api`). Ranked anchor-exact > title > anchor > prose, with snippets for body matches.

  • spec_versionFree

    Return this server's package version plus the pinned upstream commit SHA(s) the bundled data was indexed from.

  • type_getFree

    Look up a value type (`i32`, `funcref`, `v128`, …) or type form (`functype`, `limits`, `memtype`, …): classification, sibling members, defining clause prose, formal refs, and URL.

Public scan report

scanner v0.1.9 · 2026-09-26 · same rubric, same numbers if you re-run it

no findings
  • Code scan49 source files scanned25/25
  • Live reliabilityremote reachable in 329ms20/20
  • Tool poisoning9 tool descriptions checked15/15
  • Auth qualityopen endpoint, read-only tools10/15
  • Maintenancelast push 3 days ago15/15
  • Maintainer identityregistry namespace matches repository owner7/10
Overall 92/100. Components that don't apply are left out of the denominator. Any critical finding is an F.RubricAppeal a findingJSON

How wasm-mcp compares

Against every graded Web search MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score
92/100
higher than 90% of 3,470 Web search servers
Tools
9
the typical Web search server has 5
Tools that change things
0%
typical: 0%. Fewer write tools means less an agent can break
Uptime
100%
of our recent checks; the typical remote Web search server answers 100%
Response time
154 ms
faster than 78% of 2,238 Web search servers
GitHub stars
2
more than 70% of 1,786 Web search servers

What its tools let an agent do: 9 read

Install wasm-mcp in Claude Code, Cursor or VS Code

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

What the publisher says

From the wasm-mcp repository's README, as published. We do not edit it. Read it on GitHub

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

stack type signature, validation + execution prose anchors / URLs, and trap conditions (traps + can_trap), by mnemonic (i32.add) or binary opcode (0x6a).

  • spec_version — the pinned upstream commit and package version.
  • instruction_get — opcode bytes, category, introducing version,

vector, reference, parametric, variable, table, memory, control, ref, i31, struct, array, extern), introducing version, or prefix.

  • instruction_list — enumerate, filterable by category (numeric,

categories, and opcodes.

  • instruction_search — ranked free-text search across mnemonics,

forms (functype, limits, memtype, …) with defining prose.

  • type_get — value types (number / vector / reference) and type

validation, execution, binary, text), with prose, cross-references, SpecTec formal-rule references, and the rendered URL.

  • section_get — one spec clause by id / anchor (structure,

pinned WebAssembly/proposals repo), filterable by status, phase, champion, or affected spec.

  • 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

sectionget, sectionlist, 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:

local cache.

  • Read-only. No state mutation, no writes outside an optional

commit recorded in vendor/PINNED.txt.

  • Deterministic. Same input → same output, over the pinned spec

instantiates, or runs any WebAssembly or arbitrary code. Validation and reduction rules are returned as data.

  • No execution. Never compiles, validates-by-running,

indexed at build time and baked into the package.

  • No auth, no secrets, no PII. Usable anonymously.
  • No network at request time. All spec data is fetched and

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:

Shortened. The full README is on GitHub.

Nothing above is checked by us. What we check is on the safety report.

wasm-mcp: common questions

Is wasm-mcp server safe?
Yes, by our scan: it is graded A (92/100). Read the wasm-mcp safety report
How do I install wasm-mcp?
It runs remotely at mcp.xyzzylabs.ai. Add it to Claude Code, Cursor, VS Code or Claude Desktop with the snippets above, or call it through the mcp.market gateway without installing anything.
Does wasm-mcp need an API key?
Not as far as the registry entry and our scan can tell: no credentials are declared or required.
Is wasm-mcp maintained?
The last commit was 42 days ago (2026-09-23). The latest release is v0.2.16.
Is wasm-mcp up?
100% of our last 28 checks got an answer. We check remote servers about four times a day.
What can I use instead of wasm-mcp?
Servers from other publishers that do the same job: jDocmunch MCP server.
How does wasm-mcp compare with other Web search MCP servers?
safety score 92/100 (higher than 90% of 3,470 Web search servers); tools 9 (the typical Web search server has 5); tools that change things 0% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.

Alternatives to wasm-mcp

Same job from other publishers: the closest match first, then the best rated.

  • jDocmunch MCP
    Section-level doc search for .md, .rst, .adoc, .ipynb, .html, .yaml, .json, and OpenAPI specs.
    A