The Stall offers 301 component tools for research, public data and audio, plus free payment recovery. Per-tool scope applies; MCP ping is also free. Discovery is free, and paid execution follows the actual payment challenge.
Browse enabled components, declared prices and raw input/output contracts at /catalog, or the OpenAPI 3.1 spec at /openapi.json. Commercial descriptors distinguish reviewed limits from unknown legacy semantics; a declared schema is not proof of a verified outcome.
GET /cap/:name — an unpaid request returns an HTTP 402 with an x402 payment challenge in the body. Submit the on-chain USDC payment described in the challenge and retry the same request with the payment attached to receive the response.
Point an MCP-compatible client at /mcp (Streamable HTTP) or /sse (SSE). Discovery, MCP ping and payment recovery are free; paid component calls require their actual payment challenge. The MCP server card mirrors tools/list and retains raw-contract references and input-projection limitations. A2A supports payment recovery only, not component execution.