[shoedog]

Summary

Lane G C2c2e sub-slice E1 (order E2→E3→E4→E1→E5→E6): automatic fallback never silently moves a retained provider conversation to a different agent. Owner narrowed the rule on 2026-11-01 (not "permanent"): same-agent model switching on a warm session (#266) and operator/workflow-initiated cross-provider handoff with a transcript (#267) remain allowed in principle as separate features.

• executor.rs: ColdOwnershipV1 typed marker required by run_local_chain, minted only when no dispatcher is present; the existing dispatcher refusal (BindUnsupported when a dispatcher meets frozen authority) is what enforces exclusion. Comment-level change apart from the marker plumbing.
• Tests through the executor dispatcher seam with a real retained binding: a retained conversation reused across nodes and across invocations refuses on every declared rejection cause with zero successor preparation, polling or accounting rows (accounting attached, so the zero-row checks can fail), exact binding state per cause; positive control: same admission and accounting without the dispatcher activates the chain; a cold envelope-context control stays eligible.
• No production warm-workflow support added; production A2A/MCP selection still disabled.

Verification

• Implementer (Claude Code Sonnet 5.5): workspace 6,373 passed / 0 failed / 13 ignored; fmt, clippy, hygiene clean; wire SHA equals base. The new tests are already-passing controls on base (the refusal pre-existed); removing the refusal turns the retained tests RED.
• Host: fmt, clippy (a2a-bridge, bridge-workflow, -D warnings) clean; fallback_workflow 163/163; bridge-workflow 260/260; uncapped_order_and_wire_control byte-identical to base.
• Review: gpt-6.1-sol + Opus 5.5 (Opus synth) APPROVE round 1. Its material finding (retained-refusal tests ran without accounting, so zero-row checks could not fail) plus two minor items were fixed in a targeted test/comment round; orchestrator diff check.

🤖 Generated with Claude Code

https://claude.ai/code/session_017izEynabPeSUBT573AtvaZ