concepts
Fabric
Low-latency messaging inside a room: send, request/reply, fan-out, barriers.
Fabric is the coordination plane. Large artifacts belong on the drive; fabric carries small messages and references.
Patterns
| Pattern | MCP tools | Use |
|---|---|---|
| Directed send | agent_send | Fire-and-forget to one agent |
| Request / reply | agent_request | RPC-style call with timeout |
| Fan-out | agent_fanout | Publish to a topic / set of agents |
| Wait | agent_wait | Block until a message arrives |
| Barrier | barrier_arrive | N workers arrive; coordinator continues |
Identity
The host derives message source identity. Guests cannot spoof another sandbox or room in fabric fields.
REST twins
See API: Fabric for POST …/messages and POST …/barriers.
In-guest SDKs (@fystash_ai/sdk wire client, Python FystashClient) speak the native fabric protocol from inside a sandbox.