Set a Persistent Default Effort Level with CLAUDE_CODE_EFFORT_LEVEL

Claude Code defaults to medium effort, meaning extended thinking won't fire for most tasks. That's fine for everyday work — but if you always want more reasoning power, there are two ways to change this without passing a flag every time.

The quickest in-session approach is the /effort command. It sticks for the rest of that conversation:

/effort high
/effort max

But if you want a higher effort level to kick in every time Claude Code starts, set the environment variable in your global settings:

// ~/.claude/settings.json
{
  "env": {
    "CLAUDE_CODE_EFFORT_LEVEL": "max"
  }
}

This is the key distinction between --effort (a one-time CLI flag) and CLAUDE_CODE_EFFORT_LEVEL (a persistent default). The env var is applied at startup, so you never have to remember the flag again.

A few things worth keeping in mind: higher effort burns more tokens. max is intended for Opus models and gets expensive fast on long agentic runs. For most people, high makes a better persistent default, with max reserved for genuinely complex architectural or debugging sessions.

You can always override the default upward or downward for a specific session by passing --effort at startup or using /effort mid-conversation.

Pick your baseline once, and only override when the task demands it.

via @MaxGhenis