CLAUDE_CODE_NORMALIZE_PREFIX_CACHE

Updated November 6, 2026 by Alex Sorokoletov

CLAUDE_CODE_NORMALIZE_PREFIX_CACHE is a Claude Code environment variable: Set to false to disable prefix-cache normalization, or true to enable it at a 0.02 share when no server-side share is set; a server-side share between 0 and 1 takes precedence. Added in v2.1.319 and still present in v2.1.319. 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_NORMALIZE_PREFIX_CACHE=<value>
claude

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

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

Related variables

• CLAUDE_CODE_NORMALIZE_PREFIX_CACHE_VERIFY
• CLAUDE_CODE_FEDERATION_CACHE_DIR: Points at the directory holding the exchanged workload-identity-federation credential (default <config>/credentials/federation).
• CLAUDE_CODE_GROWTHBOOK_KICK_ON_WARM_CACHE: When set, triggers an early GrowthBook feature-flag fetch even when the cache is already warm.
• CLAUDE_CODE_MESSAGES_PROMPT_CACHE_TTL: Set to 5m to force the messages prompt cache to a five-minute lifetime.
• CLAUDE_CODE_PROMPT_CACHE_TTL: Sets the prompt cache TTL for the main conversation (interactive, -p, and SDK turns) to "5m" or "1h".
• ANTHROPIC_BETAS: Comma-separated beta feature headers.
• ANTHROPIC_CUSTOM_HEADERS: Custom HTTP headers (newline-separated Key: Value).
• ANTHROPIC_FEDERATION_RULE_ID

Frequently asked questions

All variables, searchable: Claude Code environment variables.