CLAUDE_CODE_TWO_STAGE_CLASSIFIER

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_TWO_STAGE_CLASSIFIER is a Claude Code environment variable: Added in v2.1.72 as an opt-in flag for two-stage intent classification. Its removal after just two versions suggests the feature graduated out of flag-gating — either enabled by default or folded into the main routing path without a toggle. Removed between v2.1.245 and v2.1.247, so current releases ignore it. 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_TWO_STAGE_CLASSIFIER=<value>
claude

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

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

Release notes that mention it

• Claude Code v2.1.74 — 2 New Environment Variables: Frame Timing & Session End Hooks
• Claude Code v2.1.72 — 6 New Environment Variables: Brief Mode, Cron Control & Two-Stage Classifier

Related variables

• CLAUDE_CODE_CLASSIFIER_SUMMARY: Carries the output of a prompt classifier as a structured summary.
• CLAUDE_CHROME_CLASSIFIER_FLOOR
• CLAUDE_PREVIEW_CLASSIFIER_FLOOR
• CLAUDE_STAGE_FILE_ROOT
• ANTHROPIC_BETAS: Comma-separated beta feature headers.
• ANTHROPIC_CUSTOM_HEADERS: Custom HTTP headers (newline-separated Key: Value).
• ANTHROPIC_FEDERATION_RULE_ID
• ANTHROPIC_ORGANIZATION_ID

Frequently asked questions

All variables, searchable: Claude Code environment variables.