Extremely narrow tracebacks

[strawgate]

Description

Rich tracebacks are extremely narrow

Example Code

Version Information

latest

[strawgate]

/marvin can you widen the tracebacks please

[marvin-context-protocol]

Claude finished @strawgate's task —— View job • claude/issue-1861-20250918-2218 • Create PR ➔

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✅ Fixed Rich traceback width issue

Todo List:

• Set up development environment
• Examine the traceback screenshot to understand the issue
• Search codebase for Rich traceback configuration
• Add console width setting to settings.py
• Update logging.py to use the width setting
• Update cli.py console to use the width setting
• Run validation commands (pre-commit, pytest)
• Commit and push changes
• Provide PR creation link

What I Fixed

The issue was that Rich Console objects were created without a width parameter, causing them to auto-detect a very narrow terminal width which made tracebacks extremely hard to read.

Changes Made

1. Added new setting rich_console_width in src/fastmcp/settings.py with a default of 120 characters
2. Updated logging configuration in src/fastmcp/utilities/logging.py to use the width setting
3. Updated main initialization in src/fastmcp/__init__.py to pass the width setting to logging
4. Updated CLI console in src/fastmcp/utilities/cli.py to use the same width setting for consistency

Usage

The default width is now 120 characters, which should provide much more readable tracebacks. Users can customize this by setting the FASTMCP_RICH_CONSOLE_WIDTH environment variable to their preferred width.

All tests pass and the code follows the repository's formatting standards.

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[strawgate]

/marvin do you think we could use shutil.get_terminal_size() wrapped in a try catch and default to like 100 if it fails?

[marvin-context-protocol]

Claude finished @strawgate's task —— View job • claude/issue-1861-20250919-0107 • Create PR ➔

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✅ Implemented dynamic terminal size detection

Todo List:

• Set up development environment
• Examine current implementation
• Modify settings to use shutil.get_terminal_size() with try-catch fallback to 100
• Update any related code that uses the setting
• Run validation commands (pre-commit, pytest)
• Commit and push changes
• Provide PR creation link

What I Implemented

Perfect suggestion! I've implemented dynamic terminal width detection using shutil.get_terminal_size() with a fallback to 100 characters (as you suggested) instead of a fixed width setting.

Changes Made

1. Added get_terminal_width() function in src/fastmcp/utilities/logging.py:11-20 that:

   • Uses shutil.get_terminal_size().columns to detect actual terminal width
   • Catches OSError and ValueError exceptions
   • Falls back to 100 characters if detection fails

2. Updated Rich Console instances to use dynamic width:

   • src/fastmcp/utilities/logging.py:55 - Main logging console
   • src/fastmcp/cli/cli.py:35 - CLI console
   • src/fastmcp/utilities/cli.py:235 - Utility CLI console

Benefits

• Dynamic adaptation - Automatically adjusts to any terminal width
• Robust fallback - Uses 100 chars when detection fails (headless environments, etc.)
• Better UX - No more extremely narrow tracebacks, but also won't be too wide on small terminals
• No configuration needed - Works out of the box without environment variables

All validation passes: ✅ pre-commit ✅ pytest (2671 tests passed)

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[dwaipayan05]

When FastMCP is deployed to Cloudwatch Console, the Rich Tracebacks continue to be as narrow. Would be nice to have this configurable or have it as big as the normal logging width. Is that not possible ? It's hard to read through these narrow tracebacks.

[strawgate]

The traceback fix landed two weeks ago and is only present in v2.12.5 -- can you confirm you're running 2.12.5 and 2.13.0 and can you share a screenshot?

Also replying to closed issues makes it harder to get help -- if you are running the latest version please open a new issue with the screenshot