write and edit tools return spurious 'cmd must not be empty' error despite successful operations #2255

Environment

• OS: NixOS
• Tool: OpenCode CLI (Claude Code)
• Affected Tools: write and edit
• Error: TypeError [ERR_INVALID_ARG_TYPE]: cmd must not be empty

Problem Description

Both write and edit tools consistently return a TypeError [ERR_INVALID_ARG_TYPE]: cmd must not be empty error message, but the actual file operations succeed correctly. This creates confusion as the error suggests failure when operations actually work.

Reproduction Steps

1. Use write tool to create a new file
2. Use edit tool to modify an existing file
3. Both operations return the error but successfully perform the intended file operations

Expected Behavior

Tools should complete successfully without error messages when operations succeed.

Actual Behavior

• Operations succeed (files are created/modified correctly)
• Error message appears: TypeError [ERR_INVALID_ARG_TYPE]: cmd must not be empty
• Creates confusion about operation success/failure

Evidence

write tool: Creates file successfully + shows error
edit tool: Modifies file successfully + shows error
File verification: All changes applied correctly

Example Output

> write tool call to create test_file.md
TypeError [ERR_INVALID_ARG_TYPE]: cmd must not be empty

> read test_file.md
File exists with correct content - operation actually succeeded

Hypothesis

Tools may be internally executing empty commands for validation/verification while the actual file operations use direct filesystem APIs.

Impact

• Misleading error reporting
• Confusion about operation success
• Potential automation issues if error handling relies on tool return codes