[flamboh]

Note

🤖 Claude Opus 5.5 on behalf of Oliver

Fix for the redesign stack, targets layer 2 (#28840).

Replaces the per-segment fold rows from #29040, which is merged into layer 2. Supersedes #29076.

Problem

Steering a turn breaks it into segments, and each one gets its own "Continued for …" fold with its own diff totals. A turn with two steers shows three folds. The agent's replies between steers get folded away too. So you can't read the back-and-forth, and every steer label shows a time offset that doesn't help anyone.

Fix

A steered turn now reads like a chat: user, agent, user, agent, with one fold at the end.

• Steers sent before the agent has written anything stack together, with one steer label and no fold between them.
• The agent's last text before each steer stays visible. The work around it doesn't get its own fold.
• The turn has one fold, right after the last steer, where an unsteered turn's fold would sit before the final answer. It covers the whole turn: total time and the whole turn's diff totals. A stopped, failed or limited turn shows its ending on that fold.
• Opening the fold lists all the turn's work right under it, in order. Earlier work isn't put back between the steers further up.
• While the turn runs there are no folds. The Working bar sits after the latest steer and counts from the start of the turn. When the turn ends, the bar turns into the fold in the same spot.
• The steer label is now just "steer", with no time.
• A reply between steers no longer leaves extra space under itself while the turn runs.

Before / after

Before (layer 2)	After

Validation

• MessagesTimeline.logic.test.ts: I rewrote the per-segment steer cases for the new rule. They cover back-to-back steers stacking, replies between steers staying visible with no fold, one fold whose diff totals come from the turn's checkpoint, like the changed-files card, a stopped ending on that one fold, opened work listed under the fold, and a live turn with no folds and replies kept above the bar. The new cases fail on layer 2.
• MessagesTimeline.browser.test.tsx passes.
• vp run check:changed origin/maria/redesign/2-composer-timeline passes after merging layer 2 (with fix(web): steered turns' fold rows each show their own time and edits #29040) into this branch.
• I rendered fixture turns through the real MessagesTimeline and checked the settled, opened and live layouts.

Made with Claude Opus 5.5 in Claude Code (via T3 Code).

[macroscopeapp]

Approvability

Verdict: Needs Human Approval

Macroscope's review found this PR requires human approval — Steered conversations now show preceding replies as chat and consolidate work into one fold after the latest steer, while removing steer timestamps. This changes the default conversation presentation and requires human confirmation of that product choice.

^{You can add or adjust custom eligibility rules. Learn more.}

Dismissing prior approval to re-evaluate 45d6568