Auto-compact not triggering at CLAUDE_AUTOCOMPACT_PCT_OVERRIDE threshold

Description

CLAUDE_AUTOCOMPACT_PCT_OVERRIDE=30 is set via settings.json env, confirmed active in the environment. Sessions consistently reach 31-34% context usage without auto-compaction triggering. Manual /compact works fine.

Environment

• Claude Code 2.1.131 (also observed on 2.1.128, 2.1.129)
• Platform: WSL2 (Ubuntu), Linux 6.6.87.2-microsoft-standard-WSL2
• Model: claude-opus-4-6[1m] (1M context)
• Settings: "env": {"CLAUDE_AUTOCOMPACT_PCT_OVERRIDE": "30"}

Expected behavior

Auto-compact should trigger when context reaches ~30% (300K tokens of 1M window).

Observed behavior

Context reaches 31-34% across multiple sessions without auto-compact firing. The env var is read correctly (confirmed via binary analysis — iF7() reads CLAUDE_AUTOCOMPACT_PCT_OVERRIDE and passes it as testPctOverride to rZ6()), but the $d_ check at end-of-turn does not trigger compaction.

Possible cause

Binary analysis of 2.1.131 shows a pfH($) gate in $d_ that was not present in earlier versions. This gate checks pfH($) && !yD$($,q) — if pfH evaluates truthy for the current model and yD$ (which checks if auto-compact window source is "env" or "settings") returns false, compaction is skipped. The env var path should make yD$ return true, but the interaction with pfH may be preventing this.

Reproduction

1. Set CLAUDE_AUTOCOMPACT_PCT_OVERRIDE=30 in settings.json env
2. Use claude-opus-4-6[1m] model
3. Run a session until context reaches 30%+
4. Observe that auto-compact does not trigger (status line shows ctx% increasing past 30%)
5. Manual /compact works normally