B7. `msg.model || DEFAULT_MODEL` declared every session without an explicit model to be
claude-code, and the parity doc recorded only the visible half of what that cost.
The durable false cut-off is real: endTurnIfAgentIsGone asked the claude sidecar about a
key it had never held, was told false, and wrote "the agent went away" into a turn that
was running fine. It survives reload, because surviving reload is what that row is for.
The same default also handed the session to adoptOrphanedSession as a claude one, which
subscribes it to that sidecar bus and pins session.model — so an opencode turn output
never arrived, and stopping it called killClaude on a key that sidecar never had. A stop
button that silently does nothing.
decideResume makes both rules explicit: the server record beats the client claim, and an
unknown harness stays unknown — no adoption, no cut-off check, just the replay. Silence
is the safe failure when the wrong answer is written durably.
DEFAULT_MODEL stays in handleAttach and is now commented as to why: that path reached its
sessionId by asking the claude sidecar to resolve a claudeSessionId, so only claude could
have answered.
First test in api/chat, which had none. websocket.ts has no seam to drive the handler
through, so the decision is extracted and tested; the wiring around it is not covered.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
pastilhasandClaude Opus 5
d9a3513cb5