Claude Skills Silently Override Instructions: Undocumented Pitfalls Exposed

A Reddit user digging into Claude Skills found multiple silent behaviors that override explicit instructions, with no documentation in skill-creator. Here's what they uncovered.

Key Pitfalls in Claude Skills

• ask_user_input_v0 hard limits: The tool enforces a maximum of 3 questions and 4 options per question. If a skill requests more, Claude silently compacts them. No error is raised.
• File write inconsistency: On Code/Desktop, Write silently overwrites existing files. On Claude.ai, create_file refuses to overwrite. Same instruction, opposite behavior.
• Relative paths in references/ are broken: The officially recommended references/ pattern doesn't resolve relative paths from the skill's directory on any platform.
• Silent fallback for missing tools: If a skill references a tool that doesn't exist on the running platform, Claude falls back to prose without any error or warning.

Practical Fixes

The author's fix: update skills to ask multiple rounds when more input is needed, bypassing the ask_user_input_v0 limits. For file operations, always use Write on Code/Desktop and create_file with platform checks on Claude.ai. Avoid relative paths in references/; use absolute paths or inline content instead.

Community-Shared Repo

Findings are being collected in a GitHub repository: github.com/livlign/claude-skills-pitfalls. Contributions welcome.

Who Should Care

Anyone building or maintaining Claude Skills, especially those relying on user input flows or cross-platform behaviors.