[Bug] Performance Degradation: Conversation Compaction Extremely Slow

Bug Description
Claude Code (Sonnet 4.5) has become extremely slow — even simple tasks like removing two fields (BondSubType) now take hours with “Compacting conversation…” stuck for a long time (context ~4k tokens), while the same operations used to run much faster before; what happened, and can it work faster again with the same quality as before?

Environment Info

• Platform: win32
• Terminal: null
• Version: 2.0.15
• Feedback ID: 32572d61-5237-4a4e-b89e-1ca6927804d1

Errors

[{"error":"AbortError: The operation was aborted\n    at abortChildProcess (node:child_process:725:27)\n    at EventTarget.onAbortListener (node:child_process:795:7)\n    at [nodejs.internal.kHybridDispatch] (node:internal/event_target:820:20)\n    at EventTarget.dispatchEvent (node:internal/event_target:755:26)\n    at abortSignal (node:internal/abort_controller:370:10)\n    at AbortController.abort (node:internal/abort_controller:392:5)\n    at Timeout._onTimeout (file:///C:/Users/s3ct/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3291:566)\n    at listOnTimeout (node:internal/timers:581:17)\n    at process.processTimers (node:internal/timers:519:7)","timestamp":"2025-10-15T12:57:19.388Z"}]