[BUG] Write file always fails with InputValidationError: file_path and content missing (v2.1.19–v2.1.20, macOS)

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?

Error: InputValidationError: Write failed due to the following issues:
The required parameter file_path is missing
The required parameter content is missing

What Should Happen?

Description

When using Claude Code on macOS, any attempt to write or modify a file consistently fails with an InputValidationError.

This issue occurs in both v2.1.19 and v2.1.20, suggesting it is not a regression introduced in a single release, but an existing bug across multiple versions.

As a result, file-writing functionality is effectively unusable.

------

Error Message

Error: InputValidationError: Write failed due to the following issues:
  The required parameter `file_path` is missing
  The required parameter `content` is missing

⎿ Error: InputValidationError: Write failed due to the following issues:
  The required parameter `file_path` is missing
  The required parameter `content` is missing

Error Messages/Logs

Steps to Reproduce

prompt:
writing the file

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.20

Platform

Other

Operating System

macOS

Terminal/Shell

Warp

Additional Information

_No response_