[BUG] Intermittent "required parameter missing" error on tool calls (Read, Edit, Bash)

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?

Describe the bug
Tool calls (Read, Edit, Bash) intermittently fail with "InputValidationError: required parameter is
missing",
even though the parameters were correctly provided. Retrying the same call usually succeeds.

To Reproduce

1. Call the Read tool with a valid file_path
2. Observe the error: "The required parameter file_path is missing"
3. Call the same tool with the same parameters again
4. It succeeds

Expected behavior
Tool calls should reliably pass parameters without intermittent failures.

Environment

• OS: macOS Darwin 24.6.0
• Shell: zsh
• Model: claude-opus-4-6 / claude-sonnet-4-6

Additional context
Affects Read, Edit, and Bash tools. Write tool was not affected during testing.

What Should Happen?

Tool calls (Read, Edit, Bash) should reliably execute with the provided parameters
every time they are invoked. The parameters passed by the model should always be
correctly received and processed by the tool handler — no intermittent drops.

Error Messages/Logs

Error Messages / Logs
  InputValidationError: Read failed due to the following issue:
  The required parameter `file_path` is missing

  InputValidationError: Edit failed due to the following issues:
  The required parameter `file_path` is missing
  The required parameter `old_string` is missing
  The required parameter `new_string` is missing

  InputValidationError: Bash failed due to the following issue:
  The required parameter `command` is missing

Steps to Reproduce

Steps to Reproduce

1. Start a Claude Code session (claude-opus-4-6 or claude-sonnet-4-6)
2. Ask Claude to perform any file operation (e.g., "read this file", "edit this line")
3. Claude invokes the Read / Edit / Bash tool with valid parameters
4. Observe: tool fails with "required parameter is missing" error
5. Claude retries the exact same tool call with the same parameters
6. Observe: tool succeeds on the second (or third) attempt

Affected tools: Read, Edit, Bash
Not affected: Write (consistently succeeded in testing)
Frequency: Intermittent — roughly 1 in 3 calls fails on first attempt

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.80 (Claude Code)

Platform

Other

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_