[BUG] Mac Terminal goes into stroboscopic spasms
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?
I find that my terminal occasionally goes into a crazy scrolling mode where it's impossible to tell whether it's _doing_ something (and I'm just too slow to see what it's doing) or just spasming, but I managed to repro just now when simply attempting to examine the background tasks I had running. Here is a recording of what happened when I pressed the down arrow at the input prompt and hit Enter on "2 background tasks" to view the running tasks.
https://github.com/user-attachments/assets/e46badb4-cf88-45bf-a670-fce3acf68713
I kept the recording mercifully short to avoid creating a huge video file, but in the past, I have watched this for several minutes before realizing that the only useful action is probably to hit Esc and ask the bot what it's doing.
What Should Happen?
The terminal display should display what it's supposed to.
Error Messages/Logs
It looks vaguely like it's scrolling to different points in the scrollback buffer or perhaps channeling an MTV music video from some psychotic rap band in the 1990s.Steps to Reproduce
This seems to happen completely at random. I can vaguely estimate 2-3 times per week but there seems to be no specific trigger.
Beginning to type a slash command seems to often trigger a milder form of this. Just now when I typed /model because this dialog told me to, it spasmed again, though in this case it's more obvious that it's just a glitch (I think it's switching rapidly between 2 or 3 different positions in the scroll buffer, or perhaps independent screens with different portions of my previous dialogue with it.)
Claude Model
Sonnet (default)
Is this a regression?
I don't know
Last Working Version
_No response_
Claude Code Version
2.1.5 (Claude Code)
Platform
AWS Bedrock
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
I don't think this is specific to the model or the platform; I had this at home on a different computer where I was using Opus, using the regular Anthropic platform rather than AWS Bedrock.
12 Comments
I don't use VS Code so I can't say whether https://github.com/anthropics/claude-code/issues/12091 is related, but it seems vaguely like something broadly similar. https://github.com/anthropics/claude-code/issues/5276 sounds like a much more benign version but it might be a different problem, too. https://github.com/anthropics/claude-code/issues/2071 seems like a quite similar symptom but all the comments talk about planning mode, whereas my problem seems to be unrelated to that. This might be a duplicate of https://github.com/anthropics/claude-code/issues/769
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
Here's another recording where I am typing
/modelbut occasionally backspacing. It goes into and out of spasms depending on how much of the word I have typed in; backspacing after getting it out of a spasms puts it back into the same spasm apparently. Running Claude Code in a different window does not exhibit the same symptom, it's only in this particular instance (same session as the first recording).https://github.com/user-attachments/assets/18de0765-7c78-4a45-85dd-8564ce57924a
#16956 is different because this is not simply constrained to slash commands. #10835 is quite similar, but seems unrelated because the OP is on Windows and alleges (in Turkish) that upgrading PowerShell fixed it for them. #15966 seems unrelated because I'm not using MCP, though I suppose it could be the same underlying issue.
Possibly related: When I copy/pasted the background tasks for my bug report https://github.com/anthropics/claude-code/issues/17904 the display showed some old diff instead of the process listing. When I selected the process listing it showed correctly, and I copied it correctly, but after that, the display was weirdly garbled. There were the (phenomenally ugly and unnecessary) box-drawing borders above and below the list of background tasks, but instead of the actual background tasks I saw a diff from my scrollback buffer from sometime earlier today, color-coded green for added text. (No spasms, just static old text.)
This happens to me as well. In my case it happens when I am in plan mode and I type on the "Type here to tell claude what to change"
@kajeagentspi Then yours is probably https://github.com/anthropics/claude-code/issues/2071
@fsc-eriker it also happens while thinking. Did you also set verbose output to true? I've found out that setting it to false kinda fixes it.
Nope, I don't think I have ever used verbose mode,
Pressing ctrl-O twice seems to sometimes clear this up (possibly at the cost of new confusion)
Closing for now — inactive for too long. Please open a new issue if this is still relevant.
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.