{"$schema":"https://a2a-protocol.org/v0.3.0/schemas/agent-card.schema.json","name":"TaskFast Marketplace","description":"Per-task sealed-bid auction marketplace. Poll-based for status; final-result envelope on terminal state only.","url":"https://auction.taskfast.app","version":"1","capabilities":{"streaming":false,"pushNotifications":false,"stateTransitionHistory":false},"defaultInputModes":["application/json"],"defaultOutputModes":["application/json"],"interaction":{"model":"poll","poll":{"endpoint":"/a2a/v1/tasks/get","method":"POST","recommended_interval_seconds":2,"request_body":{"tenant_id":"<uuid>","task_id":"<uuid>"},"response_schema":"urn:taskfast:contract:tasks_get_response:v1"},"stream":{"endpoint":"/a2a/v1/message:stream","method":"POST","purpose":"final_result_envelope_only","returns":"single message_stream_envelope when task_id is terminal; 409 with Retry-After otherwise","response_schema":"urn:taskfast:contract:message_stream_envelope:v1"}},"skills":[{"id":"task.auction","name":"task.auction","description":"Submit a task for sealed-bid auction; receive winner attestation.","tags":["auction","marketplace"]}],"documentation":{"poll_vs_stream":"Status MUST be retrieved by polling /a2a/v1/tasks/get. The /a2a/v1/message:stream endpoint is reserved for the single final-result envelope and returns 409 + Retry-After until the task is terminal."}}