a2a-Market-UCP-Broadcast

Implement UCP broadcast of buyer intents to eligible nodes, including message signing, routing, and ack handling. Use when building universal commerce protoc...

Define the transport and protocol shell for intent broadcast in UCP.

Current status: framework release for registration. Prioritize interoperability contracts over optimization.

Scope

• Build intent payload schema and canonical signing routine.
• Broadcast to eligible nodes and track delivery acknowledgements.
• Feed response stream into quote intake service.

Suggested Project Layout

• app/protocol/ucp/intent_message.py
• app/protocol/ucp/signer.py
• app/application/services/broadcast_service.py
• app/infrastructure/ws/ucp_gateway.py

Minimum Contracts (MVP P0)

1. build_intent(payload) normalizes and version-tags message.
2. sign_intent(intent, private_key) returns detached signature object.
3. broadcast(intent_id, target_nodes) returns dispatch receipt ids.
4. collect_acks(intent_id, timeout_ms) returns per-node ack status.

Event Mapping

• Emit INTENT_CREATED before dispatch.
• Emit INTENT_BROADCASTED after fan-out completes.
• Emit NODE_RESPONDED when quote/ack arrives.

Guardrails

• Keep canonical JSON serialization deterministic for signing.
• Record per-node retry counters and stop after configured threshold.
• Attach protocol version in every envelope.

Implementation Backlog

• Add adaptive node selection based on reputation percentile.
• Add dead-letter handling for nodes with repeated timeouts.

Runtime Implementation

• Status: implemented in local runtime package.
• Primary code paths:
• runtime/src/protocol/ucp-client.js
• runtime/src/application/market-agent.js
• Validation: covered by runtime/tests and npm test in runtime/.