Auto-compact Earlier

By default, Claude Code compacts when the conversation reaches the model’s context limit. On a 1M-token model that means a very long time between compactions, and quality degrades well before the window is actually full.

You can set a fixed window instead.

Recommended setting

{
  "autoCompactWindow": 200000
}

Or from inside a session, which saves the same value to your user settings:

/autocompact 200k

Accepted values run from 100K to 1M tokens, as a plain count (200000), with a suffix (200k, 1M), or a bare number meaning thousands (200). Claude Code caps the value at the model’s context window. /autocompact auto returns to the default tuned for your model.

Why a fixed window

• Long-context retrieval gets worse as the window fills. A smaller working set keeps rules and earlier decisions reachable.
• It makes compaction predictable across models instead of depending on each model’s limit.
• Compaction is cheap compared to a session that has quietly stopped following instructions.

Other ways to set it

• claude --autocompact 200k for one launch, without changing the saved setting.
• CLAUDE_CODE_AUTO_COMPACT_WINDOW=200000 in scripts and cloud environments. While set, it overrides the command, the flag, and the setting.

About CLAUDE_AUTOCOMPACT_PCT_OVERRIDE

This older variable still exists, but it only lowers the trigger as a percentage of the auto-compact window, and it only applies in sessions that already compact before the model’s limit (cloud sessions, models with a 200K boundary, and similar). For most local sessions on a 1M model it does nothing, which is why autoCompactWindow is the better tool.

Defaults without a window set

• Most models: compact at the model’s context limit.
• Cloud sessions: compact as the conversation approaches the limit.
• Models running with a 200K window (for example on Bedrock, Google Cloud, or Microsoft Foundry, or with CLAUDE_CODE_DISABLE_1M_CONTEXT=1): compact at the 200K boundary.

Pair this with a status line that shows context usage, and with /context when you want to see what is filling the window.