# wasm-mcp (remote · mcp.xyzzylabs.ai)

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

- Trust score: 64/100 (medium)
- Change this week: +4
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `mcp.xyzzylabs.ai`: 64/100 (this document), [markdown](https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp.md), [page](https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp)
- npm · `wasm-mcp`: 72/100, [markdown](https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp-2.md), [page](https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp-2)

## Channel facts

- Endpoint: `https://mcp.xyzzylabs.ai/wasm/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.2.16`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 9 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 69/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 1592 tokens (~176/item across 9 items; 9 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Capabilities**: 20/100
  - Spec-recency check failed: implements MCP spec 2024-11-05; the latest is 2026-07-28.

## Install

### Claude

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

### Codex

```toml
[mcp_servers.xyzzylabs-wasm-mcp]
url = "https://mcp.xyzzylabs.ai/wasm/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "xyzzylabs-wasm-mcp": {
      "type": "remote",
      "url": "https://mcp.xyzzylabs.ai/wasm/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add xyzzylabs-wasm-mcp --url https://mcp.xyzzylabs.ai/wasm/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  xyzzylabs-wasm-mcp:
    url: "https://mcp.xyzzylabs.ai/wasm/mcp"
```

### Other

```json
{
  "mcpServers": {
    "xyzzylabs-wasm-mcp": {
      "type": "http",
      "url": "https://mcp.xyzzylabs.ai/wasm/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-03 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 63, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 62, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-28 (score 61, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 60, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 59)

First indexed and scored.

## MCP tools (9)

### `spec_version` (~29 tokens)

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

### `instruction_get` (~146 tokens)

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).

Input parameters:

- `mnemonic` (string): Instruction mnemonic, e.g. `i32.add`. Case-insensitive, exact.
- `opcode` (string): Binary opcode hex, e.g. `0x6a` or `0xfd 0x89 0x02`. Exact.

### `instruction_list` (~133 tokens)

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.

Input parameters:

- `can_trap` (boolean): Keep only instructions that can (true) / cannot (false) trap.
- `category` (string): Instruction category.
- `introduced_in` (string): Introducing version.
- `prefix` (string): Mnemonic prefix, e.g. `i32.`. Case-insensitive.

### `instruction_search` (~52 tokens)

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

Input parameters:

- `limit` (integer): Max hits.
- `query` (string, required): Search text.

### `type_get` (~77 tokens)

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

Input parameters:

- `name` (string, required): Type or type-form name. Case-insensitive, exact.

### `section_get` (~91 tokens)

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.

Input parameters:

- `id` (string, required): Clause id or anchor.
- `spec` (string): Which spec (default core).

### `section_list` (~128 tokens)

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`.

Input parameters:

- `anchor_prefix` (string): Id/anchor prefix.
- `max_level` (integer): Cap heading depth.
- `path` (string): Source path / prefix.
- `spec` (string): Which spec (default core).
- `titled_only` (boolean): Drop anchor-only blocks.

### `spec_search` (~82 tokens)

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.

Input parameters:

- `limit` (integer): Max hits.
- `query` (string, required): Search text.
- `spec` (string): Which spec (default core).

### `proposal_list` (~117 tokens)

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`.

Input parameters:

- `affects` (string): Affected spec (finished only).
- `champion` (string): Champion substring.
- `contains` (string): Name/champion substring.
- `phase` (integer): Numeric phase 0–5.
- `status` (string): Lifecycle status.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp#diagnostics

## Score history

- 2026-08-03: 64
- 2026-08-02: 63
- 2026-08-01: 63
- 2026-07-31: 63
- 2026-07-30: 62
- 2026-07-29: 61
- 2026-07-28: 61
- 2026-07-27: 60
- 2026-07-26: 59

## Links

- Remote endpoint: https://mcp.xyzzylabs.ai/wasm/mcp
- Repository: https://github.com/xyzzylabs/wasm-mcp
- Website: https://mcp.xyzzylabs.ai/wasm/
- Changelog RSS feed: https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp/changelog.json
- HTML version of this page: https://verifymcp.io/servers/xyzzylabs-wasm-mcp/wasm-mcp