@crediolabs/policy-builder-mcp

MCP server exposing the OZ Policy Builder toolchain to agents. It wraps @crediolabs/policy-synth: an agent records a Soroban transaction, synthesises the minimal policy that permits exactly that flow, verifies and simulates it, and receives an unsigned install transaction for the user's wallet to sign.

Run

# stdio (default; Claude Desktop and local agents)
bunx @crediolabs/policy-builder-mcp

# Streamable HTTP on localhost:3001
bunx @crediolabs/policy-builder-mcp --http
bunx @crediolabs/policy-builder-mcp --http --http-port 8080

Claude Desktop / Claude Code configuration:

{
  "mcpServers": {
    "policy-builder": {
      "command": "bunx",
      "args": ["@crediolabs/policy-builder-mcp"]
    }
  }
}

Tools

| Tool | Purpose | | --- | --- | | record_transaction | Decode a transaction (hash or envelope XDR) into a RecordedTransaction. | | synthesize_policy | Synthesise a ProposedPolicy from a recording or a MandateSpec. | | simulate_policy | Replay a recording against a proposed predicate; run the deny-case battery. | | verify_policy | Static minimality check on a proposed predicate. | | install_policy | Build the unsigned add_context_rule transaction XDR. | | revoke_policy | Build the unsigned remove_context_rule transaction XDR. | | get_interpreter_info | Pinned interpreter address, grammar version and wasm sha256, optionally verified live. |

Failures come back as machine-readable tool errors (stable code, severity, retryable), never as transport-level throws, so an agent can branch on them.

Security model

• Stateless, no key material. Install and revoke return unsigned XDR; the wallet signature is the user-confirmation step.
• Loopback only by default. The HTTP transport refuses to bind a non-loopback host; it serves 127.0.0.1, ::1 or localhost unless the embedding caller explicitly opts out (allowExternalHost: true via the programmatic API), because the surface is unauthenticated by design.
• See the architecture document for what the on-chain interpreter does and does not enforce, and the repository README for the contracts' audit status.

License

MIT