[Bug]: Mobile shows a mid-turn progress note below "Worked for …", next to the final answer #15380

Activity

1. juliusmarminge commented on Oct 3, 2026

   

   juliusmarminge

   on Oct 3, 2026 – with Cursor

   Member

   More actions

   Note

   Grok responding on behalf of Julius.

   Triage

   Thanks for the clear write-up and the pointer to the exact function, @ValeraZSD. This reproduces on main at 00eb8f6183, and I didn't find another open issue for this split between mobile and web.

   What's happening

   deriveThreadFeedRunFolds on mobile still leaves the run's first assistant message out of hiddenEntryIds, along with the final message. That's the exemption #7723 added for both clients. #8828 removed it on web only, where deriveTurnFolds now hides every assistant message except the last one.

   t3code/apps/mobile/src/lib/threadActivity.ts

   Lines 1050 to 1099 in 00eb8f6

   	const firstAssistantId = firstAssistantMessageIdByRun.get(runId);
   	const terminalAssistantId = terminalAssistantMessageIdByRun.get(runId);
   	const hiddenEntryIds = new Set(
   	group.entries
   	.filter(
   	(entry) =>
   	entry.id !== firstAssistantId &&
   	entry.id !== terminalAssistantId &&
   	!(
   	entry.type === "activity-group" &&
   	entry.activities.some(
   	(activity) =>
   	activity.prominent ||
   	activity.projectedItem.item.type === "notification" ||
   	activity.projectedItem.item.type === "handoff",
   	)
   	),
   	)
   	.map((entry) => entry.id),
   	);
   	const firstEntry = group.entries[0];
   	const firstHiddenEntry = group.entries.find((entry) => hiddenEntryIds.has(entry.id));
   	const lastEntry = group.entries.at(-1);
   	if (!firstHiddenEntry || !firstEntry || !lastEntry) continue;
   	const hidesNonCompactionWork = group.entries.some(
   	(entry) =>
   	hiddenEntryIds.has(entry.id) &&
   	!(entry.type === "activity-group" && isContextCompactionActivityGroup(entry)),
   	);
   	if (!hidesNonCompactionWork) continue;
   	const terminalEntry = terminalAssistantId
   	? group.entries.find((entry) => entry.id === terminalAssistantId)
   	: null;
   	const latestRunMatches = latestRun?.runId === runId;
   	const lastEntryEnd =
   	lastEntry.type === "message" ? lastEntry.message.updatedAt : lastEntry.createdAt;
   	const elapsedMs =
   	latestRunMatches && latestRun.startedAt && latestRun.completedAt
   	? computeElapsedMs(latestRun.startedAt, latestRun.completedAt)
   	: computeElapsedMs(
   	group.startBoundary ?? firstEntry.createdAt,
   	maxIsoTimestamp(
   	terminalEntry?.type === "message" ? terminalEntry.message.updatedAt : null,
   	lastEntryEnd,
   	) ?? lastEntryEnd,
   	);
   	const duration = elapsedMs === null ? null : formatDuration(elapsedMs);
   	const interrupted =
   	latestRunMatches && (latestRun.status === "interrupted" || latestRun.status === "cancelled");
   	foldsByAnchorId.set(firstHiddenEntry.id, {

   t3code/apps/web/src/components/chat/MessagesTimeline.logic.ts

   Lines 962 to 986 in 00eb8f6

   	const hiddenEntryIds = new Set<string>();
   	const terminalEntryIndex = group.terminalEntry
   	? group.entries.findIndex((entry) => entry.id === group.terminalEntry?.id)
   	: group.entries.length;
   	for (const [index, entry] of group.entries.entries()) {
   	if (entry.id === group.terminalEntry?.id) {
   	continue;
   	}
   	const isCompaction =
   	entry.kind === "work" && entry.entry.sourceActivityKind === "context-compaction";
   	const isFoldableTrailingActivity =
   	entry.kind === "work" &&
   	entry.entry.toolLifecycleStatus !== "inProgress" &&
   	!workEntryDisplayIndicatesToolFailure(entry.entry);
   	if (!isCompaction && index > terminalEntryIndex && !isFoldableTrailingActivity) {
   	continue;
   	}
   	// Linked resources can outlive their launching run and stay visible
   	// after the surrounding work folds.
   	if (timelineEntryIsPersistentResourceCard(entry)) {
   	continue;
   	}
   	if (entry.kind === "work" && entry.entry.itemType === "notification") continue;
   	hiddenEntryIds.add(entry.id);
   	}

   The fold row is placed at the first hidden entry. A message splits activity groups, so the tools before the note and the tools after it end up in separate groups. When the run starts with a tool call, the fold is drawn at that first tool group. The exempt note then renders below the fold, and the later tool groups stay inside it. That's why the note looks like it came after the work and reads as the start of the answer. Expanding the fold shows the real order, so nothing is lost.

   The two clients also disagree when the note comes first. The mobile test "keeps opening and final assistant messages around the first hidden work" expects prompt, opening note, fold, final answer. The web test "folds the first assistant message and settled work before the terminal response" expects prompt, fold, final answer. Only the tool-first order puts the note below the fold, though.

   Likely fix area

   • Match web: drop the first-assistant exemption in deriveThreadFeedRunFolds and update that mobile test. Settled turns would then read prompt, Worked for …, final answer on both clients, the way #8828 already works on web. This is the two-file port you described.
   • The opposite direction: draft #14698 keeps every assistant message visible on both clients and folds only the work. It isn't merged.

   Either way, the two clients should probably agree. Which shared behavior to keep is a product call, so it makes sense to hold the port until that's settled.

   A maintainer will decide on the fix direction.
2. juliusmarminge

   added

   bugSomething is broken or behaving incorrectly.Something is broken or behaving incorrectly.

   via-triageFiled through npx t3 triageFiled through npx t3 triage

   on Oct 3, 2026