fix: character truncation in raw markdown mode

[jackwotherspoon]

Summary

• Fix raw markdown mode (option+m) truncating 1-2 characters at the right edge of each line
• Subtract the 2-character prefix width (✦ ) from terminalWidth before passing it to MarkdownDisplay in both GeminiMessage and GeminiMessageContent

Problem

When toggling raw markdown mode, text at the right edge of the terminal gets truncated (e.g., "remaining" becomes "remaini"). This happens because MarkdownDisplay receives the full terminalWidth but the parent layout already reserves 2 characters for the ✦ prefix. Raw markdown mode then calculates maxWidth = terminalWidth - 1 (for code block padding), but only terminalWidth - 2 characters are actually available, causing overflow and truncation.

Rendered markdown is unaffected because <Text wrap="wrap"> respects the flex container's actual width. Raw markdown mode uses an explicit width={maxWidth} on a Box, which overflows the container.

Changes

• GeminiMessage.tsx — pass terminalWidth - prefixWidth instead of terminalWidth to MarkdownDisplay
• GeminiMessageContent.tsx — same fix

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-cli]

Hi @jackwotherspoon, thank you so much for your contribution to Gemini CLI! We really appreciate the time and effort you've put into this.

We're making some updates to our contribution process to improve how we track and review changes. Please take a moment to review our recent discussion post: Improving Our Contribution Process & Introducing New Guidelines.

Key Update: Starting January 26, 2026, the Gemini CLI project will require all pull requests to be associated with an existing issue. Any pull requests not linked to an issue by that date will be automatically closed.

Thank you for your understanding and for being a part of our community!

[gemini-code-assist]

Summary of Changes

Hello @jackwotherspoon, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a visual bug in the raw markdown display mode where text was being cut off at the right edge of the terminal. The fix ensures that the available width for rendering markdown content correctly accounts for a fixed-width prefix, preventing truncation and improving the readability of raw markdown output.

Highlights

• Bug Fix: Resolved an issue where raw markdown mode (option+m) truncated 1-2 characters at the right edge of each line in the terminal display.
• Display Logic Adjustment: Modified the terminalWidth calculation in GeminiMessage and GeminiMessageContent to subtract the 2-character prefix width (✦ ) before passing it to the MarkdownDisplay component.

Changelog

• packages/cli/src/ui/components/messages/GeminiMessage.tsx
  • Adjusted the terminalWidth prop passed to MarkdownDisplay to correctly account for the prefix width.
• packages/cli/src/ui/components/messages/GeminiMessageContent.tsx
  • Modified the terminalWidth prop passed to MarkdownDisplay to subtract the prefix width.

Activity

• The author, jackwotherspoon, validated the changes on MacOS.

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[gemini-cli]

Hi there! Thank you for your contribution to Gemini CLI.

To improve our contribution process and better track changes, we now require all pull requests to be associated with an existing issue, as announced in our recent discussion and as detailed in our CONTRIBUTING.md.

This pull request is being closed because it is not currently linked to an issue. Once you have updated the description of this PR to link an issue (e.g., by adding Fixes #123 or Related to #123), it will be automatically reopened.

How to link an issue:
Add a keyword followed by the issue number (e.g., Fixes #123) in the description of your pull request. For more details on supported keywords and how linking works, please refer to the GitHub Documentation on linking pull requests to issues.

Thank you for your understanding and for being a part of our community!

[jacob314]

Please add a snapshot test to verify the new behavior is good. Give it an example with an 80 char line or something to verify that truncation happens at the right points.

[gemini-code-assist]

Code Review

This pull request correctly fixes a character truncation issue in raw markdown mode by accounting for the prefix width when calculating the available terminal width. The included review comments suggest clamping the calculated width to a minimum of zero, which prevents potential rendering issues or crashes in the edge case of a very narrow terminal window, thereby improving the robustness of the fix.

[github-actions]

Size Change: +82 B (0%)

Total Size: 24.3 MB

ℹ️ View Unchanged

Filename	Size	Change
./bundle/gemini.js	24.3 MB	+82 B (0%)
./bundle/sandbox-macos-permissive-open.sb	890 B	0 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB	0 B
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB	0 B
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB	0 B
./bundle/sandbox-macos-strict-open.sb	4.82 kB	0 B
./bundle/sandbox-macos-strict-proxied.sb	5.02 kB	0 B

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