Oh god, that was hours ago and those outputs are long gone. I was using “auto” mode, and when I switched to a Claude “thinking” mode it was able to accept the error message. One other thing I noticed though is that clicking the “add to chat” button seemed to add the output to chat (the icon for the terminal lines appeared above the chat), the agent couldn’t find the lines. But if I pasted them in manually, it could.
Anyway, a few minutes ago I switched back to “auto” and it started accepting my error messages if I paste them in or run my tests from a prompt in the chat. So, the issue seems intermittent. No indication as to what has changed, besides the clock.