[BUG] Confused by `noclobber`

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.33 (Claude Code)
• Operating System: macOS 15.5 (24F74)
• Terminal: Terminal App

Bug Description

Claude is unaware of noclobber settings and then gets confused when trying to write files with bash like echo foo > already-existing.txt. It spins its wheels a bit trying to solve the issue. If told to use >! instead of >, he gets it right, but I have to remind him of this virtually every session.

Steps to Reproduce

1. Put this in your zshrc: set -o noclobber
2. Write a file foo
3. Ask Claude to use bash to write to that file
4. Notice that you get an "file exists" error.
5. Notice Claude tries a few things and struggles to figure it out

Expected Behavior

Either Claude is aware of shell configuration and defaults to >! if necessary for the current configuration. Or, minimally, Claude recognizes file exists error and naturally knows about >! and tries again using that.

Actual Behavior

Claude spins his wheels until interrupted.

Additional Context

A workaround that seems to _usually_ work is to add this to your CLAUDE.md:

- NOCLOBBER is enabled in the zsh config. You must use >! to replace files.