CLAUDE_CODE_AUTO_MODE_COMPACT_THREAD_RULE

Updated October 23, 2026 by Alex Sorokoletov

CLAUDE_CODE_AUTO_MODE_COMPACT_THREAD_RULE is a Claude Code environment variable. Added in v2.1.299 and still present in v2.1.310. It is not in the official reference.

How to set it

For one session, export it in the shell that starts Claude Code:

export CLAUDE_CODE_AUTO_MODE_COMPACT_THREAD_RULE=<value>
claude

To apply it to every session, add it to the env object of a settings file:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_AUTO_MODE_COMPACT_THREAD_RULE": "<value>"
  }
}

Related variables

• CLAUDE_CODE_AUTO_COMPACT_WINDOW: Controls the token window threshold at which automatic context compaction kicks in.
• CLAUDE_CODE_AUTO_MODE_PRIOR_ASSISTANT_CONTEXT: Feeds prior assistant turns into the decision, so the classifier can see the reasoning behind an edit.
• CLAUDE_CODE_AUTO_MODE_SIBLING_CONTEXT: Includes sibling files (or sessions) when classifying.
• DISABLE_AUTO_COMPACT: Disable automatic compaction only (manual /compact still works).
• CLAUDE_AFTER_LAST_COMPACT: Request only conversation logs after last compaction.
• CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS: Sets the minimum conversation size, in tokens, before idle compaction runs.
• DISABLE_CLAUDE_CODE_SM_COMPACT: Disable session memory compaction.
• DISABLE_COMPACT: Disable all compaction (manual + auto).

Frequently asked questions

All variables, searchable: Claude Code environment variables.