Low-Context Execution Packet

Use branch stage/d3-09-backend-architecture.

Design only. Do not implement production services.

docs/HERMES_BACKEND_ARCHITECTURE.md must contain these sections:

1. Selected bridge protocol and evidence from D3-08
2. Pi service layout and file paths
3. Inbound listener lifecycle
4. Raw packet/log parser
5. Message schema
6. Hermes handoff rules
7. Process registry
8. Kill command sequence
9. Outbound broadcast format
10. Logging and observability
11. Failure modes and recovery
12. Implementation checklist for D3-10

Minimum message schema:

{
  "version": 1,
  "session_id": "rg40-default",
  "message_id": "uuid-or-monotonic-id",
  "source": "commander",
  "kind": "command",
  "created_ms": 0,
  "body": "text",
  "trace": {}
}

Minimum outbound string format, unless D3-08 proves a better one:

STR|<message_id>|<sender>|<escaped message>

Kill design must specify:

• how parent and children are grouped
• first graceful signal
• final SIGKILL
• timeout between signals
• log line proving cleanup

Include Mermaid flowcharts for both normal command flow and kill flow.