respec-mcp

A stdio Model Context Protocol server that wraps ReSpec rendering and adds repo-local profile discovery, so AI agents can scaffold, preflight, validate, and build W3C-style documents — Community Group reports, final reports, and explainers for TAG early design review — using policies that live in the spec repository itself, not in the MCP server.

Status: incubating. See the inline W3C discussion that led to this package being extracted from ReSpec core.

Why a separate package

ReSpec is consumed as a library by many projects. Bundling an MCP server and its ~30 transitive dependencies (Express, Hono, jose, pkce-challenge, ...) into every ReSpec install punishes every consumer for a feature only a few use. Keeping the MCP as its own package lets ReSpec stay lean and lets this server iterate on profile/policy design and security hardening independently.

What it does

Five tools over stdio:

Two MCP resources:

• respec-mcp://authoring-guide — guidance for LLMs producing W3C/CG reports.
• respec-mcp://profile/{profile_id} — resolved profile JSON.

Install

npm install -g respec-mcp

Or run without installing:

npx -y respec-mcp --repo-root /path/to/spec-repo

Quick start

1. In your spec repo, add respec-mcp.config.json:

   hljs language-json

   Copy

   {
     "default_profile": "example-cg",
     "profile_directory": "respec-mcp/profiles",
     "source_root": "reports/source",
     "build_root": "reports/build"
   }
   

2. Add a profile at respec-mcp/profiles/example-cg.json:

   hljs language-json

   Copy

   {
     "profile_id": "example-cg",
     "allowed_statuses": ["CG-DRAFT", "CG-FINAL"],
     "default_status": "CG-DRAFT",
     "default_source": "reports/source/index.html",
     "status_templates": {
       "CG-DRAFT": "respec-mcp/templates/cg-draft.html"
     },
     "required_sections": ["Abstract", "Introduction"],
     "required_links": ["https://www.w3.org/community/example/"],
     "forbidden_phrases": ["W3C Recommendation"]
   }
   

3. Point an MCP client at it:

   hljs language-json

   Copy

   {
     "mcpServers": {
       "respec-mcp": {
         "command": "npx",
         "args": ["-y", "respec-mcp", "--repo-root", "/path/to/spec-repo"],
         "transport": "stdio"
       }
     }
   }
   

Two complete worked examples ship in the repo:

• examples/example-cg/ — Community Group report.
• examples/example-explainer/ — W3C explainer skeleton following TR/explainer-explainer/.

Wiring into MCP clients

All snippets below use npx -y respec-mcp (works once the package is on npm). For local development before publishing, swap "command": "npx", "args": ["-y", "respec-mcp", ...] for "command": "node", "args": ["/absolute/path/to/respec-mcp/bin/respec-mcp.js", ...].

Replace /path/to/spec-repo with the absolute path to your W3C / CG spec repo (the one containing respec-mcp.config.json).

Claude Code (~/.claude/settings.json)

Add a respec-mcp entry under mcpServers:

{
  "mcpServers": {
    "respec-mcp": {
      "command": "npx",
      "args": ["-y", "respec-mcp", "--repo-root", "/path/to/spec-repo"]
    }
  }
}

Reload with /mcp or restart Claude Code.

Codex CLI (~/.codex/config.toml)

[mcp_servers.respec-mcp]
command = "npx"
args = ["-y", "respec-mcp", "--repo-root", "/path/to/spec-repo"]
enabled = true

Cline (VS Code extension saoudrizwan.claude-dev)

Edit ~/.config/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json (or use Cline's MCP Servers → Configure UI):

{
  "mcpServers": {
    "respec-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "respec-mcp", "--repo-root", "/path/to/spec-repo"],
      "disabled": false,
      "autoApprove": [
        "respec_list_profiles",
        "respec_preflight",
        "respec_validate"
      ],
      "timeout": 300
    }
  }
}

Only the read-only tools are auto-approved. respec_scaffold and respec_build write to disk and will prompt.

Roo Code (VS Code extension rooveterinaryinc.roo-cline)

Edit ~/.config/Code/User/globalStorage/rooveterinaryinc.roo-cline/settings/mcp_settings.json. Same shape as Cline, except Roo spells the transport type with a hyphen in its HTTP variant — for stdio the type key is still "stdio":

{
  "mcpServers": {
    "respec-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "respec-mcp", "--repo-root", "/path/to/spec-repo"],
      "disabled": false,
      "autoApprove": [
        "respec_list_profiles",
        "respec_preflight",
        "respec_validate"
      ],
      "timeout": 300
    }
  }
}

Verifying the handshake

From a terminal, send an initialize + tools/list over stdio:

printf '%s\n%s\n' \
  '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{},"clientInfo":{"name":"probe","version":"0"}}}' \
  '{"jsonrpc":"2.0","id":2,"method":"tools/list"}' \
  | npx -y respec-mcp --repo-root /path/to/spec-repo

You should see serverInfo.name: "respec-mcp" and the five tools listed.

Security

Tool inputs in MCP are LLM-controlled and can be influenced by prompt injection from document content. This server defends against that:

• Path containment. Every path input is resolved through a resolveWithinRoot check and rejected if it escapes the configured --repo-root.
• URL restriction. source accepts only relative paths or file:// URLs inside the repo root. http(s), data:, javascript: are rejected so Puppeteer never navigates to attacker-controlled URLs.
• No client-side repo_root override. The CLI flag is the boundary; the tool schema does not accept repo_root.
• Prototype pollution hardening. overrides, template_defaults, and respec_defaults are merged with key filters that drop __proto__, constructor, and prototype.

See docs/SECURITY.md for the full model.

Docs

• docs/USAGE.md — CLI flags, tool recommendations, client config.
• docs/PROFILES.md — profile and config schema.
• docs/SECURITY.md — trust boundaries and guarantees.
• docs/AUTHORING_GUIDE.md — LLM authoring guide for W3C / Community Group reports.

Docker

docker build -t respec-mcp:local .
docker run --rm -i -v /path/to/spec-repo:/workspace respec-mcp:local

The image runs as a non-root user and bakes --disable-sandbox into the ENTRYPOINT so Chromium starts cleanly.

Development

npm install
npm run test:unit          # fast, no Puppeteer
npm test                   # unit + integration (needs Chromium)

Provenance

This package was extracted from speced/respec#5168. Thanks to @marcoscaceres for the review that reshaped this into a standalone package, and to the PM-KR Community Group for the real-world report authoring workflow that motivated the design.

License

MIT. Integrates with ReSpec (W3C Software and Document License).