feat: add 'showFullOutput' command and related functionality

[B143KC47]

Summary

• Add showFullOutput command (Ctrl+O) to reveal full tool outputs that were previously truncated/saved to disk.
• Rendering tweaks show all lines when enabled and add UI hints where output was hidden.
• Tool messages load and display saved output files inline when full output is requested.

Details

• New UI state flag, key binding, description, category, and key matcher for showFullOutput; default toggle added to
  AppContainer with refresh to force re-render.
• AnsiOutput/ToolResultDisplay respect the toggle by removing height limits; MaxSizedBox hints updated with Ctrl+O
  guidance.
• ToolGroupMessage reads outputFile contents and shows them in a bordered block when full output is on; otherwise
  shows the path with a prompt to toggle.
• Test utilities and key matcher tests updated for the new command.

Related Issues

• Ability to see full shell command output Ability to see full shell command output #13809

How to Validate

• Run the CLI and trigger a command that produces truncated output saved to a file (e.g., a long shell or tool
  response).
• While viewing the tool message, press Ctrl+O to toggle full output on: saved file contents should render inline with
  “Full Output” header; hidden-line hints should disappear.
• Toggle Ctrl+O off: view returns to truncated mode with hidden-line hints and file path notice.
• Confirm Markdown toggle still works independently and other key bindings remain unchanged.

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

[google-cla]

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View this failed invocation of the CLA check for more information.

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[gemini-code-assist]

Summary of Changes

Hello @B143KC47, 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 significantly improves the user experience by allowing users to view the complete output of CLI tools directly within the terminal interface. By introducing a showFullOutput command (bound to Ctrl+O), it addresses the limitation of truncated outputs and provides a seamless way to access full logs and results that were previously saved to external files, enhancing debugging and information retrieval.

Highlights

• New Command showFullOutput (Ctrl+O): Introduces a new command to toggle the display of complete tool outputs that were previously truncated or saved to disk.
• Enhanced UI for Outputs: Adjusts rendering to remove height limits when full output is enabled and provides clear UI hints (e.g., "(Ctrl+O to show all)") where output was previously hidden.
• Inline File Content Display: Enables tool messages to dynamically load and display the contents of saved output files directly within the UI when the showFullOutput command is active.

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[gemini-code-assist]

Code Review

This pull request introduces a new showFullOutput command (Ctrl+O) that allows users to toggle the display of full tool outputs, which were previously truncated or saved to disk. The changes include updating keybindings, managing the new UI state in AppContainer, adjusting rendering logic in AnsiOutput and ToolResultDisplay to remove height limits when full output is enabled, and modifying ToolGroupMessage to load and display saved output files inline. Additionally, MaxSizedBox now provides a UI hint for the new command, and relevant test utilities have been updated. The implementation appears sound and directly addresses the described functionality.

[bdmorgan]

Hi @B143KC47, 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-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. You can easily reopen this PR once you have linked it to an issue.

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, see the GitHub Documentation.

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