[BUG]: Frequent Parenthesis Errors in Lisp Code Generation

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

When working with Emacs Lisp code, Claude Code frequently introduces parenthesis errors - either missing closing parentheses or adding too many. This breaks the code and requires manual correction.

Impact

• Generated Lisp code fails to load/compile
• Requires manual debugging to find and fix paren mismatches
• Reduces confidence in automated edits for Lisp files

Actual Behavior

• Missing closing parens in function definitions, let bindings, conditionals
• Extra closing parens added during refactoring or edits
• Inconsistent validation of paren balance

Reproducibility

Frequent - occurs regularly when editing .el files

Suggested Fix

• Add parenthesis balance validation for Lisp/Scheme code before applying edits
• Use indentation analysis to verify nesting levels
• Implement a pre-check for s-expression validity

Environment

• File type: Emacs Lisp (.el)
• Platform: Linux

What Should Happen?

Expected Behavior

• All opening parentheses should have matching closing parentheses
• Parentheses count should be validated before applying edits
• Generated code should be syntactically valid

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Open an Emacs Lisp (.el) file
2. Ask Claude to modify or refactor a function (e.g., "add error handling to this function" or "refactor this let binding")
3. Review the generated code
4. Observe parenthesis mismatches - either missing closing parens or extra parens

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

claude --version

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_