refactor(TUI): improve command menu scroll and resize mechanics by nborges-aws · Pull Request #2467 · aws/agentcore-cli

nborges-aws · 2026-09-30T00:29:34Z

Description

PR has before and after videos of behavior, make sure to scroll to bottom of description

Improves TUI behavior with optimizations to scroll and resizing mechanics.

Problem:
The command menu had some rough edges with scroll/resize behavior:

AgentCore CLI banner took up majority of available space on small terminals
Menu items overflowed the available height without scrolling
Resizing left duplicate menu items & focus carets on screen
Rows wrapping caused line separators to distort, and distortion persisted on all resizing (including enlarging terminal again)
Ink repainted the TUI each time the terminal window changed by one pixel, causing flickering when resizing terminal

Before this PR:

Screen.Recording.2026-09-29.at.8.23.01.PM.mov

Changes:

Hide the AgentCore CLI banner below a minimum terminal size (80x30)
Render each option as one clipped terminal row, which prevents wrapping (which skews the scroll calculations)
Keep highlighted command visible when resizing
Reset the scroll window when filtering changes
Add resize gating to prevent flickering
- Defer rerender until size is stable for 100ms (prevents constant flickering while resizing)
- Redraw screen once upon final dimension

After this PR:

Screen.Recording.2026-09-29.at.8.28.45.PM.mov

Type of Change

Testing

How have you tested the change?

bun run test (x pass, 0 fail)
I ran npm run test:unit and npm run test:integ
I ran npm run typecheck
I ran npm run lint
If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Checklist

I have read the CONTRIBUTING document
I have added any necessary tests that prove my fix is effective or my feature works
I have updated the documentation accordingly
I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
My changes generate no new warnings
Any dependent changes have been merged and published

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the
terms of your choice.

agentcore-devx-automation · 2026-09-30T00:32:27Z

Claude Security Review: no high-confidence findings. (run)

agentcore-devx-automation

AgentCore Harness Review

Verdict: Looks good

Nice refactor. The createResizeGate design is clean — coalescing shrink events until the gesture settles addresses the wrap-and-repaint race that the old clearScreenOnNarrowing could only mitigate, and routing Ink's resize listeners through an in-process EventEmitter while proxying dimensions keeps Ink from seeing intermediate shrink sizes. The traces I walked (shrink, shrink→grow, grow→shrink, no-op cycle) all publish exactly once at the final dimensions, and the ERASE happens before the emit so Ink's listener repaints on a cleared screen.

A few non-blocking observations for your consideration:

useScrollWindow is now unused (src/components/scrollWindow.tsx:86-95). Since CommandMenuBody now derives windowStart from highlight on every render, the hook that persisted start across renders is dead code. Worth removing (or leaving with a comment) so future readers don't wonder which is canonical.
Intentional UX change in scroll behavior? The new windowStart = max(0, highlight - floor(menuHeight/2)) (RouterScreen.tsx:260) recenters on the highlight every render, whereas useScrollWindow previously kept the window stable and scrolled only enough to keep the highlight visible. On arrow-key navigation this means every keystroke past the midpoint shifts every row, versus the older "scroll only when leaving the viewport." If that's the intended UX given the commit message, fine — flagging in case it wasn't.
BANNER_ROWS = 4 in RouterScreen.tsx:19 duplicates structural knowledge of BrandBanner (3 logo rows + divider). Since you already export MIN_BANNER_COLUMNS/ROWS from BrandBanner.tsx, consider exporting the banner height there too so it can't drift.

Resize test (tui.test.tsx) exercises the settle+coalesce behavior well; the new RouterScreen test for banner hide/restore is a good addition.

codecov-commenter · 2026-09-30T00:37:37Z

Codecov Report

❌ Patch coverage is 96.77419% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.24%. Comparing base (3e54f0c) to head (c247255).

Files with missing lines	Patch %	Lines
src/tui/resize.ts	92.13%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #2467      +/-   ##
============================================
- Coverage     97.26%   97.24%   -0.03%     
============================================
  Files           615      615              
  Lines         43665    43804     +139     
============================================
+ Hits          42471    42596     +125     
- Misses         1194     1208      +14

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

tejaskash · 2026-09-30T00:38:06Z

  const { columns, rows } = useWindowSize();
+  const bannerVisible =
+    Boolean(banner) && !hideBanner && columns >= bannerMinColumns && rows >= bannerMinRows;
+  const contentRows = Math.max(0, rows - FRAME_ROWS - (bannerVisible ? bannerHeight : 0));


[P2] Could we account for wrapped breadcrumbs and descriptions when calculating contentRows? At 40×15, scrolling the root menu to update hides the selected command because FRAME_ROWS underestimates the header height.

Updated this PR. We now are measuring the breadcrumb headers actual rendered height, including wrapped breadcrumbs and descriptions.This value is subtracted when calculating contentRows. Added a regression test to cover this case as well

tejaskash · 2026-09-30T00:38:07Z

+
+  const publish = (clear: boolean) => {
+    const changed = columns !== pendingColumns || rows !== pendingRows;
+    if (!changed) return;


[P2] Could we force a full repaint after a shrink, even if the final size matches the cached one? Resizing 100×40 → 100×15 → 100×40 with 25ms between changes skips all output here, leaving the header and selection missing until another state change.

Good callout. Updated PR so we force Ink’s cache to be invalidated when a shrink gesture lands at its original dimensions. We then follow with a repaint to the actual final size. Added a regression test covering this exact scenario

AlexanderRichey · 2026-09-30T00:44:10Z

+          addListener("prependOnceListener", event, listener);
+      }
+      if (property === "off" || property === "removeListener") {
+        return removeListener;


It looks like this is only used in tests. If so, can it be put in a test util file? That would make the intent clearer.

Oh wait, it's used in the root.

agentcore-devx-automation · 2026-09-30T00:50:10Z

Claude Security Review: no high-confidence findings. (run)

agentcore-devx-automation · 2026-09-30T00:59:39Z

Claude Security Review: no high-confidence findings. (run)

refactor(TUI): improve command menu scroll and resize mechanics

518b779

github-actions Bot added the size/m PR size: M label Sep 30, 2026

agentcore-devx-automation Bot added agentcore-harness-reviewing AgentCore Harness review in progress claude-security-reviewing Claude Code /security-review in progress labels Sep 30, 2026

agentcore-devx-automation Bot removed the claude-security-reviewing Claude Code /security-review in progress label Sep 30, 2026

agentcore-devx-automation Bot reviewed Sep 30, 2026

View reviewed changes

agentcore-devx-automation Bot removed the agentcore-harness-reviewing AgentCore Harness review in progress label Sep 30, 2026

tejaskash reviewed Sep 30, 2026

View reviewed changes

AlexanderRichey reviewed Sep 30, 2026

View reviewed changes

nborges-aws added 3 commits September 29, 2026 20:46

refactor(tui): centralize banner height

ba8306e

fix(tui): account for wrapped headers

c8fb280

fix(tui): repaint after restored resize

9ec340f

github-actions Bot added size/m PR size: M and removed size/m PR size: M labels Sep 30, 2026

agentcore-devx-automation Bot added the claude-security-reviewing Claude Code /security-review in progress label Sep 30, 2026

agentcore-devx-automation Bot removed the claude-security-reviewing Claude Code /security-review in progress label Sep 30, 2026

AlexanderRichey previously approved these changes Sep 30, 2026

View reviewed changes

test(tui): avoid platform-sensitive resize timing

c247255

nborges-aws dismissed AlexanderRichey’s stale review via c247255 September 30, 2026 00:57

github-actions Bot added size/m PR size: M and removed size/m PR size: M labels Sep 30, 2026

agentcore-devx-automation Bot added the claude-security-reviewing Claude Code /security-review in progress label Sep 30, 2026

agentcore-devx-automation Bot removed the claude-security-reviewing Claude Code /security-review in progress label Sep 30, 2026

AlexanderRichey approved these changes Sep 30, 2026

View reviewed changes

nborges-aws merged commit 95ba6ee into refactor Sep 30, 2026
18 checks passed

nborges-aws deleted the optimize-small-terminals branch September 30, 2026 01:07

Navigation Menu

refactor(TUI): improve command menu scroll and resize mechanics - #2467

refactor(TUI): improve command menu scroll and resize mechanics#2467
nborges-aws merged 5 commits into
refactorfrom
optimize-small-terminals

nborges-aws commented Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot left a comment

Uh oh!

codecov-commenter commented Sep 30, 2026 •

edited

Loading

Uh oh!

tejaskash Sep 30, 2026

Uh oh!

nborges-aws Sep 30, 2026

Uh oh!

tejaskash Sep 30, 2026

Uh oh!

nborges-aws Sep 30, 2026

Uh oh!

AlexanderRichey Sep 30, 2026

Uh oh!

AlexanderRichey Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Conversation

nborges-aws commented Sep 30, 2026

Description

Type of Change

Testing

Checklist

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot left a comment

Choose a reason for hiding this comment

AgentCore Harness Review

Uh oh!

codecov-commenter commented Sep 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

tejaskash Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

nborges-aws Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

tejaskash Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

nborges-aws Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

AlexanderRichey Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

AlexanderRichey Sep 30, 2026

Choose a reason for hiding this comment

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

agentcore-devx-automation Bot commented Sep 30, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

codecov-commenter commented Sep 30, 2026 •

edited

Loading