Agent chat: a long tool output that wraps past eight rows collapses with Show more by teamleaderleo · Pull Request #24463 · manaflow-ai/cmux

teamleaderleo · 2026-10-23T04:51:59Z

Leo's words (2026-10-22 21:28Z): "also the tool calling i think there should be more of like a "show more" type thing for long outputs or whatnot..."

Leo-ask: ask-c57e055a4e

What base already does

#23413 (merged 2026-10-21 15:59Z, after the 03960f5 nightly Leo's app runs) already collapses a tool block longer than eight lines:

its first eight lines show under a 28px bottom fade;
"Show all N lines" opens it in place, and "Show less" closes it;
the button is keyboard reachable, and Find in Chat opens the block.

That covers a call's output, a command's Shell block and an edit's diff.

The gap this fixes

The cap counted newlines only. Output wraps by default, so a result with a few long lines (a one-line JSON result, a minified log line) wrapped to dozens of rows with no cap and no toggle.

Change

A call's output and a Shell block whose few lines wrap past eight rows are now cut at eight rows the same way, with "Show more"; "Show less" closes them. Blocks cut by line count keep "Show all N lines".
The shipped look is Agent chat: tool blocks wrap or fade at the right edge, preview fades, no resize cursor over a docked chat #23413's, unchanged: same max-height, fade, button and strings.
"Show more" reuses the existing message.more string (21 locales, from cmux NEXT agent chat: long prompts collapse to ten lines with Show more; pasted blocks are chips #23431's long prompts). No new strings.
The new hook (useWrapsPast) lives in BlockParts.tsx. In ToolRow.tsx and ShellBlock.tsx only the usePreview inputs and the card's root attributes change; the <pre> lines that Agent chat: long lines in diff and command cards show a thin scrollbar at rest #23967 and Agent chat: tool results show their content, not the JSON envelope around it #24030 edit are untouched.

Before / after (synthetic gallery fixtures, `agent-pane.tool-output-collapse`, Linux Chromium)

Before (base `4c3b775`)	After, collapsed	After, Show more clicked

Light: . The line-cut case is unchanged:

Live before/after: scripts/gallery-compare.sh → /compare/tp-tool-output-showmore/ on the gallery host (tailnet).

Versions tried (gallery experiment `tool-output-collapse`, Compare arms)

fade-link (shipped): 8 rows, bottom fade, text link	six-bar: 6 rows, fade, full-width quiet bar	ten-chip: 10 rows, hard cut, corner chip	fifteen-link: 15 rows, fade, link

I picked fade-link because it is closest to Claude Code and the Codex app, which show a few lines and then a quiet "Show more" under the block. It is also the look #23413's line-cut blocks and #23431's long prompts already use, so the transcript keeps one collapse.

The chip covers the last visible line.
The bar is heavier than the row it serves.
Fifteen rows is a tall preview in a narrow pane.

The other arms stay in the gallery for comparison. Nothing changes for anyone by default beyond the wrapped-rows cut.

Performance

The collapse itself is CSS (the existing [data-preview="cut"] max-height, now var(--cv-preview-rows, 8)).
Rows are read only for a block that is drawn (an opened call), whose output has 8 or fewer lines, wraps, and has a line of 24 or more characters. A read is one scrollHeight plus one computed style, in a layout effect, when that block's own text, wrap or line count changes. No per-frame loop, and nothing per token for any other row.
Observer: one ResizeObserver on that block's own body, so a narrower or wider chat re-reads it. Stop condition and cleanup: it is disconnected when the block's text changes, when it stops wrapping or fits by line count, and when it unmounts.
No hot path changed for closed rows, so there is no before/after number.

Find

The text is drawn whole and only clipped, so Find counts it. A Find reveal bumps reveal, which opens the block, as for line-cut blocks (tested).

Tests

webviews/test/transcript-wrapped-output-preview.test.tsx covers:

cut with Show more, then Show less, with the control a real button that Find skips;
no toggle at 8 rows or fewer;
narrowing and widening re-read the block;
Wrap lines off is not cut;
the Shell block;
a Find reveal opens the block;
a whole block is never cut;
the experiment arm sets the rows;
the shipped arm still cuts at 8.

Observed / Not run

Ran on huge-blue at f3474b1:
- the new file plus transcript-block-overflow, transcript-output-copy, permission-edit-diff, agent-pane-edited-card-expand and the shell tests: 57 pass, 0 fail;
- gallery agent-pane-entries, manifest, play and play-names tests: pass;
- vp fmt --check and vp lint on the changed files: clean;
- type check: no errors in changed files;
- acpmux-protocol check: pass.
Base findings, not from this PR:
- gallery-coverage fails the same way at 4c3b775;
- vp fmt --check flags src/pages/settings/components/HostSections.tsx;
- CI reds are release-notary, Guard status and cmux-next checks (NO-SWIFTUI allowlist, Swift type-scale baseline, perf_gate_unlit). They are the same reds as Agent chat: tool results show their content, not the JSON envelope around it #24030.
Not run: no Swift change, so no app compile is needed.

Changelog

Fixed: A long tool output whose lines wrap past eight rows now collapses with Show more in agent chats.

Agent session: cosmic-gray

🤖 Generated with Claude Code

…ses with Show more A tool block already showed its first eight lines under a fade with Show all N lines (#23413), but it counted newlines only: a one-line JSON result or a minified log line wrapped to dozens of rows with no cap and no toggle. Those are now cut at eight rows too, with Show more, and Show less closes them. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Agent-Session: https://cmux.com/deeplink/agent?harness=claude&session=01a16030-bf28-7072-b1f6-b83bbd0beacc&host=cosmic-gray

github-actions · 2026-10-23T04:52:11Z

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review f3474b1: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr24463 -f ref=tp-tool-output-showmore -f platform=macos -f backend_mode=local

Probably yours: accent-glass-invariants.test.ts fails here but not on main's latest full suite. Seen on other PRs too (likely flaky): agent-pane-adopted-tool-calls.test.ts, composer-type-scale.test.ts, composer-type-scale.test.ts and 4 more.

CI failed on f3474b1a74 (run 39903556961 attempt 1): 1 code, 1 unknown.

Job	Verdict	Why
web / react-apps-check (1)	code	a web test failed
web / react-apps-check	unknown	no known signature; failed step: `Check webview test shards`

Failures:

new in this PR accent-glass-invariants.test.ts no orange or system accent and no opaque glass on 1845 gallery stages: failed (job)
seen on other PRs agent-pane-adopted-tool-calls.test.ts the adopted turn's Worked for opens to its commands and edited files: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer new-chat draws its text on the type scale: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer footer-essentials draws its text on the type scale: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer footer-full-access draws its text on the type scale: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer footer-essentials-new-chat draws its text on the type scale: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer agent-home draws its text on the type scale: failed (job)
seen on other PRs composer-type-scale.test.ts agent-pane.composer agent-home-path draws its text on the type scale: failed (job)

Matched log lines

web / react-apps-check (1): (fail) no orange or system accent and no opaque glass on 1845 gallery stages [337761.25ms]

Not re-run automatically: web / react-apps-check (1), web / react-apps-check are not machine failures.

Written by scripts/ci/classify_failures.py (ci-failure-attribution.yml); signatures are its SIGNATURES table. A machine verdict is the runner's fault, not this PR's; yours means the failing file is one this PR changes, also red on main that main's latest full suite fails the same way, seen on other PRs that it failed on another pull request's run lately.

red: cmux-next checks (god files, concurrency, crash safety, l10n); NEW: red check: Checks job structure (+2 more) is not red on the base 740e58f; do not merge until green; see lane-rules
red: web / Web status; no finished base run on 740e58f to compare; do not merge until green; see lane-rules
red: web / react-apps-check; no finished base run on 740e58f to compare; do not merge until green; see lane-rules
red: web / react-apps-check (1); no finished base run on 740e58f to compare; do not merge until green; see lane-rules

Gallery before/after for f3474b1: 16 states rendered, 1 images differ, 1643 more touched states not rendered. Images are in the run's artifact, not on this public PR.

gh run download 39903557002 -R manaflow-ai/cmux -n gallery-advisory-24463-f3474b1a74657b2ea1418e2439323579906cf0ce (then read gallery-review.json)

States

State	Theme	Status	Diff	Picked by
`agent-pane.chat-find-bar/empty`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/empty`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/matches`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/matches`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/next-match`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/next-match`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/no-results`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.chat-find-bar/no-results`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/last-turn`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/last-turn`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/toolbar`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/toolbar`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/tree-selection`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/tree-selection`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/open-file-error`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/open-file-error`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/escape`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/escape`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/review-file`	Apple System Colors	changed	0%	own `conversation.css`
`agent-pane.diff-panel/review-file`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/stage-hunk`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/stage-hunk`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/more-lines`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.diff-panel/more-lines`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/file`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/file`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/folder`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/folder`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/outside-lock`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/outside-lock`	Apple System Colors	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/outside-text`	Apple System Colors Light	unchanged	0%	own `conversation.css`
`agent-pane.path-chip/outside-text`	Apple System Colors	unchanged	0%	own `conversation.css`

_{Pick other states with a Gallery: entry.id, entry.id/variant line in the PR body.}

teamleaderleo · 2026-10-23T04:52:57Z

Owned by transcript-parity on cosmic-gray · session

teamleaderleo · 2026-10-23T04:52:57Z

Owned by nx-chat on big-red · took over from session 01a16030

blacksmith-sh · 2026-10-23T04:55:06Z

Found 25 test failures on Blacksmith runners:

Failures

Test	View Logs
`---/---`	View Logs
`---/---`	View Logs
`---/---`	View Logs
`---/---`	View Logs
`/tmp/tmp4dxkl_4l/summary-missing.json (live):/summary-missing.json (live):`	View Logs
`/tmp/tmp_z8bb0df/summary-fail.json (live):/summary-fail.json (live):`	View Logs
`[tabs] debug.tab_switch timed 0 of 40 switches/` `[tabs] debug.tab_switch timed 0 of 40 switches`	View Logs
`[tabs] debug.tab_switch timed 0 of 40 switches/` `[tabs] debug.tab_switch timed 0 of 40 switches`	View Logs
`[tabs] the window draws no frames/[tabs] the window draws no frames`	View Logs
`[tabs] the window draws no frames/[tabs] the window draws no frames`	View Logs

...and 15 more test failures. View all on Blacksmith: run 39903556961, run 39903556998, run 39903556878

^{Need help on this PR? Tag @codesmith-bot with what you need.}

teamleaderleo · 2026-10-23T04:59:03Z

cmux-next guards / nightly-guards / workflow-guard-tests / release-notary is red on 12 of 17 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

teamleaderleo · 2026-10-23T04:59:15Z

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › Checks job structure is red on 9 of 11 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

teamleaderleo · 2026-10-23T04:59:26Z

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › No new SwiftUI (macOS UI is AppKit) is red on 9 of 11 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

teamleaderleo · 2026-10-23T05:01:06Z

Bead cx-rkgqg created for this PR by the cmux coordinator.

Four looks for a long tool output's collapse (8 rows + fade + link, the shipped one; 6 + fade + bar; 10 + hard cut + chip; 15 + fade + link), compared in the new agent-pane.tool-output-collapse gallery entry. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Agent-Session: https://cmux.com/deeplink/agent?harness=claude&session=01a16030-bf28-7072-b1f6-b83bbd0beacc&host=cosmic-gray

teamleaderleo · 2026-10-23T05:09:00Z

cmux-next / cmux-next checks (god files, concurrency, crash safety, l10n) › Script tests (pin-cmux-tui, embed-cef, ensure-cef store) is red on 8 of 13 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

teamleaderleo · 2026-10-26T02:29:18Z

Orphaned: no activity for 69 h, and no lane holds a lease on it. The orphan sweep could not merge feat-cmux-next in: conflicts in webviews/src/agent-session/acpmux/conversation/ShellBlock.tsx, webviews/src/agent-session/acpmux/conversation/ToolRow.tsx, webviews/src/agent-session/acpmux/conversation/conversation.css, webviews/src/experiments/registry.ts. Listed for a lane to resolve.

teamleaderleo · 2026-10-26T05:30:54Z

Stale (13d, conflicts); rebuild fresh from feat-cmux-next if still wanted

teamleaderleo · 2026-10-27T14:58:20Z

Stale (13d, conflicts); rebuild fresh from feat-cmux-next if still wanted. Added to nx-chat stale backlog.

teamleaderleo added the risk:normal Risk tier (docs/ci/risk-tiers.md) label Oct 23, 2026

teamleaderleo mentioned this pull request Oct 23, 2026

cmux NEXT session rail grows with content #24574

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teamleaderleo closed this Oct 26, 2026

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Agent chat: a long tool output that wraps past eight rows collapses with Show more - #24463

Agent chat: a long tool output that wraps past eight rows collapses with Show more#24463
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What base already does

The gap this fixes

Change

Before / after (synthetic gallery fixtures, agent-pane.tool-output-collapse, Linux Chromium)

Versions tried (gallery experiment tool-output-collapse, Compare arms)

Performance

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Tests

Observed / Not run

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Before / after (synthetic gallery fixtures, `agent-pane.tool-output-collapse`, Linux Chromium)

Versions tried (gallery experiment `tool-output-collapse`, Compare arms)

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