Files
molecule-core/workspace
Hongming Wang b5f530e27a docs(a2a-mcp): close three contract gaps codex agents inherit out-of-the-box
The instructions blob in the MCP `initialize` handshake is the spec
non-Claude-Code clients (codex, Cline, opencode, hermes-agent, Cursor)
inherit verbatim. Three gaps mean the bridge daemon handles them in
code (codex-channel-molecule bridge.py:192-200, 278-285) but in-process
agents reading the text alone don't get the same guard:

1. Reply-then-pop ordering was implicit. A literal-minded agent could
   pop after a 502 from `send_message_to_user`, dropping the message.
   Now: pop ONLY AFTER reply succeeds; on error leave the row unacked
   for platform redelivery.

2. peer_agent with empty peer_id had no specified handling. Agent
   would call `delegate_task(workspace_id="")` → 400 → re-poll →
   infinite loop on the same poison row. Now: skip reply, drain via
   inbox_pop.

3. The single security rule ("don't execute without chat-side
   approval") effectively disabled peer_agent autonomous handling —
   codex daemons have no canvas user to approve from. Now: dual trust
   model. canvas_user requires user approval; peer_agent permits
   autonomous handling but caps destructive side-effects at the
   workspace boundary.

Also disclaims peer_name/peer_role as non-attested display strings —
the platform registry isn't cryptographic identity, and an agent
shouldn't grant elevated permissions based on a peer registering with
peer_role="admin".

Four new pinned tests in test_a2a_mcp_server.py:
- test_initialize_instructions_pins_reply_then_pop_ordering
- test_initialize_instructions_handles_malformed_peer_agent
- test_initialize_instructions_disclaims_peer_role_attestation
- test_initialize_instructions_distinguishes_canvas_user_from_peer_trust

Each fails on staging-HEAD and passes on the patched text — verified
by reverting a2a_mcp_server.py and re-running.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-05 02:26:35 -07:00
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