[BUG] Background color bleed in terminal from chalk usage

Thanks for the report! Are you able to reproduce this issue?

Yeah, it happens every time.

macOS (lines 290-302): Uses AppleScript to launch Terminal.app
  applescript = f"""
  tell application "Terminal"
      activate
      do script "{script_path.absolute()} {self.workspace_path.absolute()}"
      set custom title of front window to "{self.terminal_title}"
  end tell
  """
  subprocess.run(["osascript", "-e", applescript], check=True, capture_output=True, text=True)

After the terminal is launched, we automatically copy some instructions to clipboard and then run claude

     # Try to copy instructions to clipboard automatically
     echo ""
     echo "Preparing agent instructions..."

     # Check if pbcopy is available (macOS)
     if command -v pbcopy &> /dev/null && [ -f "PASTE_ME_INTO_CLAUDE.txt" ]; then
         cat PASTE_ME_INTO_CLAUDE.txt | pbcopy
         echo ""
         echo "[OK] Instructions copied to clipboard!"
         echo "[!] Just paste (Cmd+V) when Claude Code starts"
         echo ""
         echo "Starting Claude Code in 3 seconds..."
         sleep 3
     else
         # Show manual copy instructions
         echo ""
         echo "================================================================"
         echo "    📋 COPY THIS INTO CLAUDE CODE:                           "
         echo "================================================================"
         echo ""
         cat PASTE_ME_INTO_CLAUDE.txt | head -20
         echo ""
         echo "... [Full content in PASTE_ME_INTO_CLAUDE.txt]"
         echo ""
         echo "👆 Open PASTE_ME_INTO_CLAUDE.txt for full instructions"
         echo "📋 Copy the contents and paste into Claude Code"
         echo ""
         echo "Press Enter when ready to start Claude Code..."
         read -n 1
     fi

     # Start Claude Code
     echo ""
     echo "Starting Claude Code..."
     claude

I have the same issue with multiple CLI tools that use colored background. My guess it that Claude Code just needs to always reset the terminal colors after showing any terminal output.

Seeing a similar issue every time I run claude code.

<img width="1725" alt="Image" src="https://github.com/user-attachments/assets/c0e8b878-c433-4a21-9e4d-ffe16e8efb91" />
<img width="1723" alt="Image" src="https://github.com/user-attachments/assets/ad6a9623-055d-4548-9829-d69728818c34" />
<img width="1720" alt="Image" src="https://github.com/user-attachments/assets/c9a1b98e-a467-4326-97fe-4cd4e25cbd9e" />

Seeing this too - combination of red and white sometimes randomly disappears

same

same

same

Issue appears consistently inside a GNU Screen (https://www.gnu.org/software/screen/) session.

same with pterm (go)

<img width="1970" height="2154" alt="Image" src="https://github.com/user-attachments/assets/1ebcf7dd-8a29-4cae-8ffb-45a3e924f75b" />

<img width="1204" height="292" alt="Image" src="https://github.com/user-attachments/assets/2fef9dde-95e5-4cb7-857d-93ccd82d928e" />

Same issue happens in Claude Code terminal on Windows:

Description: When Claude executes code blocks (e.g., running Laravel tests with php artisan test), the terminal output changes color but the background color remains stuck in that color even after the command completes.

Example:

Claude runs: php artisan test --filter "some test"
Terminal output shows in green background when tests complete successfully
After test completion, terminal background remains green instead of returning to default

Expected Behavior: Terminal background should reset to default color after command execution completes.
Current Behavior: Background color persists, making subsequent terminal output difficult to read.

I can also reproduce in gnu screen

Also a problem for me. Makes claude nearly unusable.

As a workaround, ask claude to run "tput sgr0" and it will reset it. Obviously the app should do this or something similar directly, but for anyone experiencing this, that will fix it.

I use an ugly workaround for now. I created a PostToolUse:Bash hook that runs the following script

#!/usr/bin/env bash

tput sgr0 >&2
echo "COLORS HAVE BEEN FIXED" >&2
exit 1 # ensures that stderr is shown to user only

+1. Makes it nearly unusable in my macOS terminal app :/

Same here

+1

Same running testing tools from Composer or NPM (like phpstan or unit tests):

<img width="1515" height="535" alt="Image" src="https://github.com/user-attachments/assets/a2c894aa-4087-4a8f-b454-899e16454b1c" />

<img width="1442" height="632" alt="Image" src="https://github.com/user-attachments/assets/30cfb911-286b-4b90-ab36-8f326b71c2cb" />

Yes, getting it on my side as well. This bug should be very easy to fix. And is affecting readability a lot.

Same issue when running tests.

Same here running tests.

Did someone get the solution?

<img width="390" height="108" alt="Image" src="https://github.com/user-attachments/assets/d523c17c-c1c8-4072-957b-bfda848779e0" />
I think I'm seeing this too.

This is consistently reproducible with gnu-screen on macos. I've tried everything to match up terminal emulation and background color erase between the two---to no avail. /opt/homebrew/bin/claude is minified, which would be time consuming to debug and patch.

The only work around I've found is to not use claude in a screen session or to disable colors when using screen with:

FORCE_COLOR=0 claude

At least Claude >2.0 seems to reset the color once a new prompt is submitted.

At least Claude >2.0 seems to reset the color once a new prompt is submitted.

90% better than what it was. I think they definitely took this into account for version 2.

At least Claude >2.0 seems to reset the color once a new prompt is submitted.

I noticed. It is a whole lot better than "forever bleeding until a patch is done" that did a "reset" of the background. The bleeding remained even after closing CC. I was doing a reset manually with color 07 command. And sometimes copy pasting the code from console to text editor to read, since the white/gray over green background was killing my eyes. Fortunately, I completed that project already.

This issue has been inactive for 30 days. If the issue is still occurring, please comment to let us know. Otherwise, this issue will be automatically closed in 30 days for housekeeping purposes.

This is absolutely still occurring, and it's EXTREMELY annoying. From what I can tell, no one at Anthropic has ever tested this?

For me, its on linux.

<img width="767" height="700" alt="Image" src="https://github.com/user-attachments/assets/1adc93fc-171f-4183-bfbd-154dfb321922" />

This is basically unusable. I have to continuously resize the terminal to actually be able to read what the damn thing is saying.

fwiw it is not happening on tmux for me

Hmmmm, interesting. I'm running this in screen. If I do not use screen, I don't get the color garbage.

This is still occurring with screen

yep... wanted to use screen to continue the work while I move home and got the issue!

I have this issue:

https://github.com/anthropics/claude-code/issues/20459

seems similar but a little different.

<img width="1887" height="1121" alt="Image" src="https://github.com/user-attachments/assets/9d6426fd-5f59-4ade-a874-869a10decb12" />

This issue has been preventing me from upgrading to newer versions. I would love to use the latest version with colors enabled, but unfortunately, due to this color bleeding bug, I've had to remain on version 2.1.2.

I understand the team has many priorities, but it would be greatly appreciated if this could be addressed when possible — especially since the fix appears to be relatively straightforward (adding proper reset sequences). Thank you for your work on Claude Code.

still happening with screen on linux

Any updates or workarounds on this?