Real-server runtime observations (synthetic data; Chromium web client, 1280x800, dark theme).
Both servers started with T3CODE_DEV_SEED=0. Replay (dev) uses the real ACP adapter.
Same interaction: complete multi-turn; select todo-list live; settle; un-settle; select multi-turn.

Before 0a333a69e781be3208224006d344a5fb39355e76
Capability error toast visible: true
Saved model from real CLI thread show: todo-list
Next real CLI send --wait: {"status": "completed", "reply": "todo list fixture complete", "error": null}
Persisted next-run record (ordinal | model selection | status): 2|{"instanceId":"devReplay","model":"todo-list"}|completed

After 21d76f81a835d589f24066d7e06f8279db91e4de
Capability error toast visible: false
Saved model from real CLI thread show: multi-turn
Next real CLI send --wait: {"status": "completed", "reply": "first fixture turn complete", "error": null}
Persisted next-run record (ordinal | model selection | status): 2|{"instanceId":"devReplay","model":"multi-turn"}|completed

The composer locally displays the attempted pick even when the base server rejects it; that label is not evidence of persistence.
No unit tests were used as proof.