Initial release.
- Envelope, fifteen-code error taxonomy, feature negotiation.
- Session lifecycle: hello / welcome / bye, heartbeats, ack, list_jobs.
- Job lifecycle: submit / accepted / event* / result | error / cancel.
- Subscribe across sessions with optional replay.
- Agent versioning (
name@version), inventory, default resolution. - Lease enforcement with optional
expires_atandcost.budget. - Event kinds: log, thought, tool_call, tool_result, status, metric, artifact_ref, delegate, progress, result_chunk.
- Streamed results via
JobContext.StreamResult. - Transports: in-memory, WebSocket (coder/websocket), stdio NDJSON.
- Middleware: nethttp, chi, otel.
arcpCLI withserveandsubmitsubcommands.