Model configuration

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Available models

For the model setting in Claude Code, you can either configure:

• A model alias
• A full model name
• For Bedrock, an ARN

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Model aliases

Model aliases provide a convenient way to select model settings without remembering exact version numbers:

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Setting your model

You can configure your model in several ways, listed in order of priority:

1. During session - Use /model <alias|name> to switch models mid-session
2. At startup - Launch with claude --model <alias|name>
3. Environment variable - Set ANTHROPIC_MODEL=<alias|name>
4. Settings - Configure permanently in your settings file using the model field.

Example usage:

# Start with Opus
claude --model opus

# Switch to Sonnet during session
/model sonnet

Example settings file:

{
    "permissions": {
        ...
    },
    "model": "opus"
}

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Special model behavior

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default model setting

The behavior of default depends on your account type.

For certain Max users, Claude Code will automatically fall back to Sonnet if you hit a usage threshold with Opus.

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opusplan model setting

The opusplan model alias provides an automated hybrid approach:

• In plan mode - Uses opus for complex reasoning and architecture decisions
• In execution mode - Automatically switches to sonnet for code generation and implementation

This gives you the best of both worlds: Opus’s superior reasoning for planning, and Sonnet’s efficiency for execution.

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Extended context with [1m]

For Console/API users, the [1m] suffix can be added to full model names to enable a 1 million token context window.

# Example of using a full model name with the [1m] suffix
/model anthropic.claude-sonnet-4-20250514-v1:0[1m]

Note: Extended context models have different pricing.

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Checking your current model

You can see which model you’re currently using in several ways:

1. In status line (if configured)
2. In /status, which also displays your account information.

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Environment variables

You can use the following environment variables, which must be full model names, to control the model names that the aliases map to.

Note: ANTHROPIC_SMALL_FAST_MODEL is deprecated in favor of ANTHROPIC_DEFAULT_HAIKU_MODEL.