CLAUDE_CODE_EFFORT_LEVEL
Updated by Alex Sorokoletov
CLAUDE_CODE_EFFORT_LEVEL is a Claude Code environment variable: Reasoning effort: low, medium, or high (default). Controls adaptive thinking depth [4]. Removed in v2.1.284, so current releases ignore it. It is listed in the official reference.
| Status | Removed in v2.1.284 |
|---|---|
| Added | Present since v2.1.69 or earlier |
| Category | Models and thinking |
| Official docs | Listed |
How to set it
For one session, export it in the shell that starts Claude Code:
export CLAUDE_CODE_EFFORT_LEVEL=<value>
claudeTo apply it to every session, add it to the env object of a settings file:
// ~/.claude/settings.json
{
"env": {
"CLAUDE_CODE_EFFORT_LEVEL": "<value>"
}
}Release notes that mention it
- Claude Code v2.1.76 — 3 New Environment Variables: MCP Elicitation and Worktree Improvements
- Claude Code v2.1.70 — 3 New Environment Variables and 1 Removed
- 83 Undocumented Claude Code Environment Variables (v2.1.19)
Related variables
CLAUDE_CODE_ALWAYS_ENABLE_EFFORT: Force-enable reasoning effort level regardless of other settings.CLAUDE_EFFORT: Set thinking effort level at spawn time without the interactive /effort picker.CLAUDE_CODE_MAX_EFFORT_REMINDERANTHROPIC_CUSTOM_MODEL_OPTIONANTHROPIC_CUSTOM_MODEL_OPTION_DESCRIPTIONANTHROPIC_CUSTOM_MODEL_OPTION_NAMEANTHROPIC_CUSTOM_MODEL_OPTION_SUPPORTED_CAPABILITIESANTHROPIC_DEFAULT_FABLE_MODEL
Frequently asked questions
What does CLAUDE_CODE_EFFORT_LEVEL do?
Reasoning effort: low, medium, or high (default). Controls adaptive thinking depth [4]
Which Claude Code version has CLAUDE_CODE_EFFORT_LEVEL?
Removed in v2.1.284, so current releases ignore it.
How do I set CLAUDE_CODE_EFFORT_LEVEL?
Export it before starting Claude Code (export CLAUDE_CODE_EFFORT_LEVEL=value), or add it to the "env" object in ~/.claude/settings.json to apply it to every session.
All variables, searchable: Claude Code environment variables.