[Bug] Prompt cache invalidation causing excessive token consumption on minor edits

Bug Description
Subject: Excessive token burn and logic regression in latest session. Issue: Claude Code consumed ~30% of my 5-hour quota in just 10 minutes for minor edits. Cache Invalidation: The tool seems to be re-reading the entire context window every turn despite minimal changes. Logic Errors: Claude failed to prioritize correct units (e.g., suggested 'Kilogram' instead of 'Gram' for '100 g' input) and UI overlaps on dropdowns. Efficiency: I had to manually guide it to fix basic CSS/logic issues that should have been trivial. Please investigate why the prompt caching is failing so aggressively in this session.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.114
• Feedback ID: f3e9c4ee-0ae3-4104-9976-5aa0a59d6829

Errors

[{"error":"Error: Failed to delete keychain entry: security: SecKeychainSearchCopyNext: The specified item could not be found in the keychain.\n    at Jwq (/$bunfs/root/src/entrypoints/cli.js:253:283620)\n    at async Apq (/$bunfs/root/src/entrypoints/cli.js:406:898)\n    at async iE6 (/$bunfs/root/src/entrypoints/cli.js:406:796)\n    at async hq_ (/$bunfs/root/src/entrypoints/cli.js:2727:2084)\n    at async ZDH (/$bunfs/root/src/entrypoints/cli.js:2752:5698)\n    at async <anonymous> (/$bunfs/root/src/entrypoints/cli.js:2776:3358)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-20T15:31:27.913Z"},{"error":"AxiosError: timeout of 5000ms exceeded\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:115:13344)\n    at emit (node:events:92:22)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:114:3321)\n    at request (/$bunfs/root/src/entrypoints/cli.js:117:2467)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-20T16:30:18.300Z"},{"error":"Error: Request was aborted.\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:3448)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-20T16:30:57.959Z"}]