CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS is a Claude Code environment variable: Sets the minimum conversation size, in tokens, before idle compaction runs. The value is floored at 100,000 and defaults to 200,000 when unset. Idle compaction itself is controlled by a feature gate with off, log, and compact modes and fires at 90% of the threshold by default. Added in v2.1.290. Added in v2.1.290 and still present in v2.1.294. It is listed in the official reference.

How to set it

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

export CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS=<value>
claude

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

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

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-290

Related variables

• CLAUDE_CODE_FILE_READ_MAX_OUTPUT_TOKENS: Max tokens for file read output.
• CLAUDE_CODE_IDLE_TOKEN_THRESHOLD: Works alongside CLAUDE_CODE_IDLE_THRESHOLD_MINUTES to gate when the idle-return prompt appears.
• CLAUDE_CODE_MAX_CONTEXT_TOKENS: Sets an explicit ceiling on the context window size used during a session.
• CLAUDE_CODE_MAX_OUTPUT_TOKENS: Maximum output tokens; validated per-model.
• MAX_MCP_OUTPUT_TOKENS: Max tokens for MCP tool output.
• MAX_THINKING_TOKENS: Likely controlled via API settings now.
• CLAUDE_BG_SOCKET_TOKENS_PATH
• CLAUDE_CODE_TOTAL_TOKENS_REMINDER

Frequently asked questions

All variables, searchable: Claude Code environment variables.