CLAUDE_CODE_INVESTIGATE_FIRST

Updated October 13, 2026 by Alex Sorokoletov

CLAUDE_CODE_INVESTIGATE_FIRST is a Claude Code environment variable: Instructs the agent to read and investigate before acting — enforcing "read before write." Converts an agent that might immediately start editing into one that first gathers context. Likely injected as a meta-instruction into the system prompt. Removed between v2.1.222 and v2.1.224, 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_INVESTIGATE_FIRST=<value>
claude

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

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

Release notes that mention it

• Claude Code v2.1.123 — Background Daemons, Agent Fleets, and CoWork Memory

Related variables

• CLAUDE_CODE_EXIT_AFTER_FIRST_RENDER: Exit after first UI render (testing).
• CLAUDE_SLOW_FIRST_BYTE_MS: Default 30,000ms.
• CLAUDE_CODE_CCR_FOLD_FIRST_TURN_RESCAN
• ANTHROPIC_BETAS: Comma-separated beta feature headers.
• ANTHROPIC_CUSTOM_HEADERS: Custom HTTP headers (newline-separated Key: Value).
• ANTHROPIC_FEDERATION_RULE_ID
• ANTHROPIC_ORGANIZATION_ID
• ANTHROPIC_WORKSPACE_ID

Frequently asked questions

All variables, searchable: Claude Code environment variables.