[Bug] Claude Code performance degradation affecting Opus and Sonnet models

Bug Description
Sonnet is stuck in some kind of dunce-loop
I described a bug that it introduced, provided reasonably clear instructions and expectations, but it continues to go through the following loop:

• thinking for 15-30 minutes, never saying anything and not reporting the token count other than a few hundred tokens at beginning and end of these lengthy bouts of "thinking"
• It gets compacted, after which it continues "thinking" for a while
• Eventually it claims to have the "solution", which it proceeds to implement without asking for permission
• Its "solution" is literally the thing that I told it was the problem
• I call it out
• Again, it spends almost 30 minutes "thinking", and gets compacted
• It "thinks" for a while longer and eventually comes back with the "solution"
• It again does not ask for confirmation and just starts making changes
• The "solution" that it implemented was again to double down on the very thing it was supposed to be fixing
• I call it out, it starts thinking...

Environment Info

• Platform: linux
• Terminal: vte-based
• Version: 2.1.98
• Feedback ID: 7595e874-615e-48bd-8ee1-b6216920b0d5

Errors

[{"error":"Error: Request was aborted.\n    at JS$ (/$bunfs/root/src/entrypoints/cli.js:1248:11933)\n    at next (native:1:11)\n    at Rx7 (/$bunfs/root/src/entrypoints/cli.js:7840:9194)\n    at next (native:1:11)\n    at xx7 (/$bunfs/root/src/entrypoints/cli.js:7845:11444)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-10T10:36:48.107Z"},{"error":"Error: Request was aborted.\n    at JS$ (/$bunfs/root/src/entrypoints/cli.js:1248:11933)\n    at next (native:1:11)\n    at Rx7 (/$bunfs/root/src/entrypoints/cli.js:7840:9194)\n    at next (native:1:11)\n    at xx7 (/$bunfs/root/src/entrypoints/cli.js:7845:11444)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-10T11:10:56.508Z"}]