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title: Complexity Source MCP emoji: 📚 colorFrom: indigo colorTo: purple sdk: docker app_port: 7860 pinned: false short_description: Read-only sources and fantasy entity cards for AI systems.

Complexity Source MCP

Read-only Model Context Protocol server that gives an AI access to verifiable sources and a managed fantasy knowledge catalog instead of asking it to fill missing facts from memory.

The server is built with the official @modelcontextprotocol/sdk and exposes ten tools:

• read_web_source — public HTML, JSON, XML, and text sources;
• read_github_source — one GitHub repository file at an explicit ref;
• read_local_source — one UTF-8 file inside an allowed root;
• search_local_sources — bounded filename and content search;
• read_image_source — PNG, JPEG, GIF, or WebP for vision-capable clients;
• list_source_policy — active roots, limits, and provenance policy.
• search_fantasy_catalog — search canonical fantasy entity cards;
• get_fantasy_entity — read one card and its direct relations;
• trace_fantasy_relations — traverse a bounded entity relation graph;
• fantasy_catalog_status — aggregate catalog readiness and counts.

Every retrieved source carries its canonical URI, retrieval timestamp, and SHA-256 fingerprint. Text is paginated instead of silently discarded.

Fantasy catalog

The included Aethoria seed is an original, internally consistent fantasy dataset. It contains structured cards for worlds, locations, factions, characters, creatures, artifacts, quests, and events. Relations between cards let an agent answer questions that require several facts without inventing missing lore.

MongoDB is the storage layer. Configure an administrative environment and seed the catalog once:

cp .env.example .env
# Set MONGODB_URI in .env.
npm run seed:fantasy

The Docker image seeds these cards idempotently at startup when MONGODB_URI is configured. The HTTP/MCP surface exposes only read-only catalog tools. There is deliberately no public ingestion tool: visitors cannot add or modify cards.

Security boundary

• All MCP tools are annotated read-only.
• Local paths are restricted to SOURCE_ROOTS; symbolic-link escapes fail.
• Loopback, link-local, private network, and cloud metadata URLs are blocked.
• SOURCE_ALLOWED_HOSTS can restrict web access to an explicit hostname list.
• Credential-like files (.env, private keys, package credentials) are refused.
• Downloads are limited to 8 MiB and text calls to 50,000 characters.
• No tool can create, edit, move, or delete content.
• MongoDB credentials stay server-side and are never returned by MCP tools.

This server provides source material. It does not guarantee that the connected model will interpret the material correctly, so the UI should retain and show the returned provenance beside generated answers.

Install and run

git clone https://github.com/Complexity-ML/complexity-source-mcp.git
cd complexity-source-mcp
npm install

SOURCE_ROOTS=/absolute/path/to/your/sources npm start

npm start uses MCP over stdio, which is the normal transport for a local AI client. An optional loopback HTTP transport is available for local development:

SOURCE_ROOTS=/Users/boris/Dev npm run start:http

It listens on http://127.0.0.1:8790/mcp. Set PORT or HOST to override the listener.

Hugging Face Space

The repository is directly deployable as a Hugging Face Docker Space. The container listens on port 7860 and exposes:

• GET / — readiness and server metadata;
• POST /mcp — MCP Streamable HTTP requests.

The hosted container deliberately restricts local-file tools to the empty public-sources directory. Web and GitHub source tools remain available, and private-network URLs remain blocked.

After deployment, configure AI LAB with:

SOURCE_MCP_URL=https://YOUR-SPACE.hf.space/mcp

Free Spaces can sleep while idle. AI LAB therefore treats source grounding as an optional service and reports its live connection state in the Agent panel. Configure MONGODB_URI as a Space secret and MONGODB_DATABASE as a variable before seeding. If the Space is private, also configure SOURCE_MCP_TOKEN as a secret in the website deployment; AI LAB sends it as a Bearer token.

MCP client configuration

{
  "mcpServers": {
    "complexity-sources": {
      "command": "node",
      "args": [
        "/absolute/path/to/complexity-source-mcp/src/cli.js"
      ],
      "env": {
        "SOURCE_ROOTS": "/absolute/path/to/your/sources"
      }
    }
  }
}

Multiple source roots use the operating-system path separator (: on macOS and Linux). For example:

SOURCE_ROOTS="/path/to/papers:/path/to/code"

Optional environment variables:

• GITHUB_TOKEN — read private GitHub sources using the token's own scopes;
• SOURCE_ALLOWED_HOSTS — comma-separated web host allowlist;
• PORT and HOST — HTTP development transport only.
• MONGODB_URI — server-side MongoDB connection string;
• MONGODB_DATABASE — catalog database name (defaults to complexity_fantasy).

Never commit a GitHub token. Prefer a fine-grained, read-only token limited to the repositories the AI is allowed to inspect.

Verify

npm test
npm run smoke

The smoke test connects an official MCP client to the server through the official in-memory transport, lists the tools, and calls the policy tool.