"Turn finished · no closing message" kept appearing over an agent that was
plainly still working, with output resuming a moment later.
isGenerating was set in exactly three places: sendPrompt, and the two reconnect
handshakes. So it answered "am I waiting for a reply I asked for", never "is
this conversation working". Every other way a turn begins left it false — a
commander waking on its own schedule, a queued prompt the server delivered,
another tab driving the same session, or a turn that started before this tab
was looking. The events still render, but buildRows reads isGenerating to
decide whether the last turn is finished, so a live turn was `complete` and the
moment it sat on a completed tool call with nothing said after it, the banner
fired. Same gap left the composer enabled mid-turn, and a message typed then
was not marked injected — which splits the live turn and prints the banner a
second way, the exact failure injected exists to prevent.
session:claude now sets it: the harness's own turn-start signal, and the only
one that arrives before any work does. tool:start sets it too, because
session:claude is not durable and a socket connecting mid-turn never receives
one, while a tool cannot start outside a turn.
Two candidates were measured rather than argued. A genuinely silent turn ending
earns the banner honestly, but 667 of 673 recorded turns end with
assistant:text immediately before result, so that is ~1% and cannot be it. And
a stale sync:live is real but rare: correlating every attach in the officer log
against the agent's own later output, 15 of 549 "not generating" attaches were
contradicted and one provably so. That residue is left alone — the tool:start
fallback now corrects it on the next event — and noted on the refresh card,
which is the same seam.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Officer-Session: f7a62308-0977-4cf4-aa29-c020853fd420
