[BUG] Bash tool pollutes user shell history with internal wrapper commands

[AdamDrewsTR]

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description:

Claude Code's Bash tool pollutes the user's ~/.bash_history with internal command wrapper markers, making shell history essentially unusable across all terminal sessions.

Environment:

• Claude Code version: v2.0.55
• Shell: bash
• OS: macOS (Darwin 23.6.0)

Issue:

When Claude Code executes bash commands, it wraps them with markers like: { echo BEGIN___COMMAND_OUTPUT_MARKER; cd /path && some_command; EC=$?; echo "BEGIN___COMMAND_DONE_MARKER$EC"; }

These wrapped commands are written to ~/.bash_history, causing:

1. Severe history pollution: 96% of history (480/500 lines) were Claude Code wrappers in my case
2. System-wide impact: All bash terminals share the same history file, so every terminal session is affected
3. Unusable history: Ctrl+R search and up-arrow navigation become nearly impossible

What Should Happen?

Expected behavior:

Claude Code's internal command execution should not write to user's personal shell history.

Suggested solutions:

1. Set HISTFILE=/dev/null before executing wrapped commands
2. Use set +o history to disable history recording for internal commands
3. Use a separate history file like ~/.claude_code_history
4. Unset HISTFILE temporarily during command execution

Workaround:

Users can add this to ~/.bashrc: export HISTIGNORE="BEGIN___COMMAND_OUTPUT_MARKER:BEGIN___COMMAND_DONE_MARKER"

And clean existing pollution with: grep -v "___BEGIN___COMMAND" ~/.bash_history > ~/.bash_history.clean && mv ~/.bash_history.clean ~/.bash_history

Impact: High - affects all Claude Code users with bash shells, severely degrades terminal UX

Error Messages/Logs

Steps to Reproduce

eproduction Steps:

1. Check your current bash history: wc -l ~/.bash_history grep -c "___BEGIN___COMMAND" ~/.bash_history
2. Note the baseline numbers.
3. Start a Claude Code session in any project: cd /path/to/any/project claude
4. Ask Claude Code to run several bash commands:

Run git status Run ls -la Run grep -r "function" src/ | head -10

4. Exit Claude Code and check history again: exit wc -l ~/.bash_history grep -c "___BEGIN___COMMAND" ~/.bash_history
5. Open a new bash terminal and press up-arrow or Ctrl+R: - You'll see Claude Code's wrapper commands instead of your actual command history - Example pollution: { echo BEGIN___COMMAND_OUTPUT_MARKER; cd /path && grep -r "function" src/ | head -10; EC=$?; echo "BEGIN___COMMAND_DONE_MARKER$EC"; }

Expected Result:

• Only actual user commands in ~/.bash_history
• Clean, usable command history across all terminals

Actual Result:

• ~/.bash_history filled with Claude Code wrapper commands
• In severe cases, 90%+ of history is pollution
• History search (Ctrl+R) and navigation (up-arrow) become unusable system-wide

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.0.55

Platform

Other

Operating System

macOS

Terminal/Shell

Other

Additional Information

No response

[AdamDrewsTR]

Comparison to Similar Tools:

GitHub Copilot CLI has its own history issues (https://github.com/github/gh-copilot/issues/65, https://github.com/github/gh-copilot/issues/99), but does NOT pollute user history with internal execution wrappers. Their issues involve:

• History corruption/deletion bugs
• Shell function wrapper compatibility problems

Claude Code's issue is unique: internal command execution mechanics leak into user's personal history and persist indefinitely.

Expected Behavior:

Claude Code's internal command wrappers should:

1. Never write to ~/.bash_history
2. Execute in a history-disabled context
3. Be invisible to the user's shell history across all terminals

Impact: Critical

• Affects 100% of Claude Code users with bash shells
• Pollution persists indefinitely, even when not actively using Claude Code
• Severely degrades terminal UX system-wide (history search, navigation)
• Can reach 90%+ pollution rate with regular Claude Code usage
• No automatic cleanup - requires manual intervention

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