Auto-compact stopped working in v2.1.62+ (regression from v2.1.50)

Bug Report: Auto-compact regression

Summary: Auto-compact (trigger: auto) stopped firing completely in v2.1.62 and v2.1.63. It worked reliably in v2.1.50 and earlier. Sessions now run all the way to 0 tokens remaining without auto-compact triggering.

Version regression data

Pulled from session JSONL files (~/.claude/projects/.../), looking at compact_boundary events:

| Version | Date | Auto compact triggers | Manual compact triggers |
|---------|------|-----------------------|------------------------|
| v2.1.39 | Feb 12 | 2 | 0 |
| v2.1.49 | Feb 23 | 12 | 0 |
| v2.1.50 | Feb 23 | 7 | 0 |
| v2.1.62 | Feb 28 | 0 | 3-5 |
| v2.1.63 | Feb 28 | 0 | 0-2 |

In v2.1.49/2.1.50, auto-compact fired correctly and logged events like:

{
  "type": "system",
  "subtype": "compact_boundary",
  "content": "Conversation compacted",
  "compactMetadata": {
    "trigger": "auto",
    "preTokens": 169714
  }
}

In v2.1.62/2.1.63, no trigger: auto events appear at all. Only trigger: manual events (user-initiated via Ctrl+R) appear.

Configuration

~/.claude/settings.json:

{
  "env": {
    "CLAUDE_CODE_MAX_OUTPUT_TOKENS": "64000",
    "CLAUDE_AUTOCOMPACT_PCT_OVERRIDE": "75"
  }
}

This setting was working correctly in v2.1.50 - auto-compact fired at ~167k-180k tokens (roughly 75-90% of 200k context window). In v2.1.62+ it never fires at all, causing sessions to hit the context ceiling.

Environment

• Platform: Windows 11 Pro
• IDE: Antigravity IDE
• Model: claude-sonnet-4-6
• Current version: v2.1.63

Impact

Without auto-compact, long sessions (common for multi-step coding tasks) run to 0 context remaining, forcing a session restart and losing conversational context. Previously auto-compact would seamlessly extend sessions.

Workaround

Manually compact with Ctrl+R before context is exhausted.