Affixio MCP

Local stdio MCP server that wraps the affixio SDK. It gives agents a signed yes or no record that an action happened on the host.

The SDK stays as it is: install with npm i affixio. This package only adds a local MCP front end for catalog listings and platform wraps.

Run it with npx @affixio/mcp. PII never leaves the host: tool arguments are hashed, never stored, and proving runs offline on the machine.

Install

npm i -g @affixio/mcp
affixio-mcp

Or without installing:

npx -y @affixio/mcp

Check it works:

affixio-mcp probe

Client config

Claude Desktop config file, Examples dir has ready files:

{
  "mcpServers": {
    "affixio": {
      "command": "npx",
      "args": ["-y", "@affixio/mcp"],
      "env": {
        "AFFIX_API_KEY": "local_operator",
        "AFFIX_MCP_HOME": "${HOME}/.affix-mcp"
      }
    }
  }
}

Cursor uses the same mcpServers shape. Copy examples/claude-desktop-mcp.json or examples/cursor-mcp.json.

Tools

Only three tools ship. No identity, age, KYC, MRZ, passport, licence, vehicle, admin, OAuth, or cloud passthrough. Those stay on the Hub MCP.

• attest_action: action plus optional outcome, context hash, policy id. Returns a signed action attestation with timestamp, action id, ML-DSA-65 signature, and proof id.
• verify_action: attestation or receipt in, valid true or false plus reason out.
• gate_tool_call: tool name plus args hash or summary plus policy in, allow or deny plus signed decision out. Call before privileged agent tool calls.

Env config

• AFFIX_API_KEY: licence key, defaults to local_operator for offline use
• AFFIX_API_BASE: override API base, unset means SDK default
• AFFIX_MCP_HOME: state dir, defaults to ~/.affix-mcp
• AFFIX_MCP_AGENT_ID: default agent id
• AFFIX_MCP_ALLOWED_TOOLS: comma list, empty means any tool may attest
• AFFIX_MCP_MAX_AMOUNT: optional numeric cap, denies above it
• AFFIX_MCP_CURRENCY: currency code, default GBP
• AFFIX_MCP_BLOCKED_PATTERNS: comma list, default sk_live_, AKIA, PRIVATE KEY

Security

Local first. Proving runs offline via the affixio SDK in HMAC mode, signed ML-DSA-65. Gate decisions are fail closed: unknown tools, over-limit amounts, blocked arg patterns, and malformed proofs all deny. Raw tool args never persist; the record keeps a sha256 digest only.

Dev

npm install
npm test
npm run probe

License

Apache-2.0. See LICENSE.