CLAUDE_CODE_PROMPT_CACHE_TTL

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_PROMPT_CACHE_TTL is a Claude Code environment variable. Removed between v2.1.245 and v2.1.247, so current releases ignore it. 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_PROMPT_CACHE_TTL=<value>
claude

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

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

Release notes that mention it

• Claude Code Version Tracker: Undocumented Env Vars, Feature Gates & Models
• claude-code-env-vars-v2-1-245

Related variables

• CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT: Switches to a reduced system prompt, stripping out the non-essential guidance sections that bulk up the default prompt.
• CLAUDE_CODE_SYSTEM_PROMPT_GB_FEATURE: Names a GrowthBook feature flag whose value overrides the system prompt — but only when CLAUDE_CODE_REMOTE is set.
• CLAUDE_CODE_VERIFY_PROMPT: The verify flow was reworked; the standalone prompt override no longer maps to how verification runs.
• CLAUDE_CODE_APPEND_PROMPT_HEAD
• CLAUDE_CODE_FEDERATION_CACHE_DIR
• CLAUDE_CODE_GROWTHBOOK_KICK_ON_WARM_CACHE
• CLAUDE_CODE_HOST_PROMPT_SUPERSEDES_RECORD
• CLAUDE_CODE_MORNING_BRIEF_PROMPT

Frequently asked questions

All variables, searchable: Claude Code environment variables.