drawcommons-ledger-mcp

Read-only MCP server for a public audit ledger. Zero dependencies (Python standard library only, stdio transport). No accounts, no API keys, no write path.

Beta. The ledger currently holds 4 structural samples with fake IDs, not real records, and the governing protocol is published for comment but not yet in force. Cite these numbers only with that caveat attached.

Run

uvx drawcommons-ledger-mcp                  # or: pip install drawcommons-ledger-mcp

Client configuration (Claude Desktop / Cursor / Claude Code):

{
  "mcpServers": {
    "ledger": {
      "command": "uvx",
      "args": ["drawcommons-ledger-mcp"]
    }
  }
}

Point it at another deployment with --base https://your-host (or LEDGER_BASE).

Tools

ledger_verify does not trust the server's ok. It fetches the entries and the export, recomputes sha256(prev_hash + "\n" + canonical(entry)) for every entry on the calling machine, checks that each prev_hash links to the previous hash, and recomputes the anchor from the exported bytes. Verdicts: agree, chain_broken (with the first bad index), server_disagrees (the server's own numbers contradict the entries it served).

A tool that merely repeats the upstream conclusion turns an upstream error into "verified". That is the one thing this package exists to avoid.

Boundaries

1. Read-only, one address. The base URL is fixed at launch; tool arguments cannot change it (otherwise the server becomes an open proxy on the caller's machine).
2. Bytes, not facts. A complete hash chain only proves the bytes you fetched match what was chained. Someone can record a false entry honestly, and the chain stays valid.
3. Beta. Fields may change with the ledger version, which is why no outputSchema is declared: declaring one would promise the fields never grow or shrink.

Source, tests and the Chinese-language docs: https://github.com/leigui-888/drawcommons/tree/main/repo/examples/04-mcp-server

License

Apache-2.0 (full text: https://github.com/leigui-888/drawcommons/blob/main/repo/LICENSE). The data the API returns is CC-BY-4.0: attribution required, commercial use allowed.