[BUG] Tool usage output no longer shows executed command in versions > 1.0.123

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?

Starting with version 1.0.124, tool usage output no longer displays the actual command/parameters that were executed. Users only see the command result output, making it impossible to monitor what actions Claude is taking.

What Should Happen?

Tool usage output should display both:

1. The command/tool that was executed (with parameters)
2. The result/output of that execution

This was the behavior in version 1.0.123 and earlier.

Error Messages/Logs

No error messages - this is a display regression where information is missing from the UI.

Steps to Reproduce

1. Install Claude Code version 1.0.124 or later
2. Ask Claude to run any tool (e.g., Bash tool with ls command)
3. Observe that only the command output is shown
4. Compare with version 1.0.123 where both command and output were visible

Claude Model

Sonnet (default)

Is this a regression?

Yes

Last Working Version

1.0.123

Claude Code Version

1.0.126

Platform

Anthropic API

Operating System

macOS and Linux (LMDE 6) - tested on both

Terminal/Shell

Various (affects all terminals)

Additional Information

Impact: High - Without visibility into tool execution, users cannot monitor or debug Claude's actions effectively.

Affected Tools: All tools including:

• Built-in Bash tool
• MCP tools
• Other native tools

Workaround: Downgrade to version 1.0.123 using claude install 1.0.123

Testing: Confirmed working in 1.0.123, broken in 1.0.124, 1.0.125, and 1.0.126.

This regression significantly impacts the transparency and debuggability of Claude Code sessions.