[Bug] Context compaction triggered prematurely at 83% remaining with 1M context window

Bug Description
compaction triggered at 83 percent context remaining, despite 1m context window size.. clearly something with the threshold didnt scale to 1m and is left at 256k

Environment Info

• Platform: darwin
• Terminal: kitty
• Version: 2.1.75
• Feedback ID: 988f4302-9bbe-4282-8e8c-eaa13cb44a93

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/eyal/.local/share/claude/versions/2.1.75 (expected in multi-process scenarios)\n    at XvT (/$bunfs/root/src/entrypoints/cli.js:2416:2025)\n    at gbq (/$bunfs/root/src/entrypoints/cli.js:2416:1169)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-13T22:41:03.651Z"}]