[BUG] Excessive terminal BEL with Claude Code

Environment

• Platform (select one):
• [ ] Anthropic API
• [X] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.103 (Claude Code)
• Operating System: MacOS 15.6.1 (24G90) Sequoia
• Terminal: Terminal App

Bug Description

Claude Code beeps at me when it wants my attention, which is good; but it also beeps excessively when I switch from my Terminal window to some other window, and back.

I got rid of this behavior briefly with reset but then once I foregrounded Claude again, the problem came back.

Running od -tx2 on the command prompt initially displays just

^[[O^[[I^[[O^[[I

as I click out of the window, back in, back to my browser, back to the terminal. Typing ctrl-D reveals repeated sequences of

5b1b    1b4f    495b

I have many other Terminal windows open and none of them exhibit this behavior (not even one where I also ran claude briefly) but it seems clear to me that this is caused by Claude.

Steps to Reproduce

1. Run Claude. Background it. (Return with fg if you like.)
2. Click outside terminal window; hear annoying beep
3. Click inside Claude's terminal window; hear another

Originally I was guessing this only happens when you interact with Claude in a way which requires it to go away for a while and Do Its Thing, but after further experimentation I have updated this section.

Expected Behavior

Beep when you actually want my attention, but not all the time when I click between windows.

Actual Behavior

Beeps every time I switch to and from this terminal window

Additional Context

The problem seems to go away after you /exit Claude, but I want to be able to background it and do other stuff in the terminal between prompts.