# Claude Code: how to change the model with /model or --model

> Switch models mid-session, at launch, with an environment variable or in settings, and find out which one wins when they disagree.

URL: https://claudegpt.si/news/claude-code-how-to-change-model  
Published: 2026-10-29T06:50:44.115Z  
Author: ClaudeGPT Si Newsroom  
Section: Guides  
Topics: Claude Code, Anthropic, Claude, Settings  
Publisher: ClaudeGPT Si

## Key takeaways

- Type /model in a session, or launch with claude --model <alias>, to switch models.
- A model set with --model, ANTHROPIC_MODEL or the model setting follows a fixed priority, and project or managed settings can override your choice.
- Aliases include opus, sonnet, haiku, fable, best and opusplan, and the 1M-context variants sonnet[1m] and opus[1m].

Claude Code how to change model: type `/model` during a session and pick one, or start Claude Code with `claude --model <name>`. Both are documented in the [Claude Code model configuration docs](https://code.claude.com/docs/en/model-config), which also cover the environment variable and settings file routes. Which one wins depends on where you set it, and that is where most people get stuck.

This guide is for anyone who uses Claude Code in a terminal and wants to switch between models like Opus, Sonnet and Haiku, or make a choice stick. The details below were read from the official docs on October 29, 2026. Model names and defaults change, so check the docs if something here looks off. If you haven't set Claude Code up yet, start with [how to install it](https://claudegpt.si/news/claude-code-how-to-install).

## The five ways to set the model

The docs list them from highest priority to lowest:

| Priority | Method | How long it lasts |
| --- | --- | --- |
| 1 | `/model <alias or name>` in a session | Switches now. Also saved as your default, unless you choose otherwise |
| 2 | `claude --model <alias or name>` | That session only |
| 3 | `ANTHROPIC_MODEL=<alias or name>` | Sessions launched with the variable set |
| 4 | The `model` field in a settings file | Every session that reads the file |
| 5 | `ANTHROPIC_DEFAULT_MODEL=<alias or name>` | Default for new sessions, only if nothing above picks a model |

`ANTHROPIC_DEFAULT_MODEL` needs Claude Code v2.1.236 or later.

## How to change the model during a session

Run `/model` with no argument to open the picker, or give it a name:

```text
/model sonnet
```

In the picker, `Enter` switches and saves the choice as your default for new sessions, by writing the `model` field in your user settings. Press `s` instead to switch for this session only.

You can also switch without clearing what you've typed. The interactive mode docs list `Option+P` on macOS and `Alt+P` on Windows and Linux for this. On macOS, your terminal must treat Option as Meta for that shortcut to work.

One cost to know about: each model has its own prompt cache, so the first request after a switch re-reads the whole conversation without the cache, according to the [settings docs](https://code.claude.com/docs/en/settings).

## How to start Claude Code on a specific model

Use the `--model` flag. It takes an alias or a full model name, and it overrides both the `model` setting and `ANTHROPIC_MODEL`:

```bash
claude --model opus
```

To pin an exact version, use the full name, such as `claude --model claude-sonnet-5`. The flag applies only to the session you start with it.

## How to set a default model

For a default that survives restarts, use one of these.

**Settings file.** Add a `model` field to a settings file:

```json
{
  "model": "opus"
}
```

The file you pick sets who it applies to:

| File | Applies to |
| --- | --- |
| `~/.claude/settings.json` | You, in every project |
| `.claude/settings.json` | Everyone in the project, if committed |
| `.claude/settings.local.json` | You, in this one project |

The docs give an example of the local file at work. If your team's shared file sets one model and you want another, put yours in `.claude/settings.local.json` and only your sessions change.

**Environment variable.** Export it before launching:

```bash
export ANTHROPIC_MODEL=opus
claude
```

`ANTHROPIC_MODEL` beats the `model` key in any settings file. `ANTHROPIC_DEFAULT_MODEL` does the opposite: it applies only when no file sets `model`.

**One session without saving.** Pass settings inline:

```bash
claude --settings '{"model": "claude-opus-5-5"}'
```

## Model aliases you can use

As of October 29, 2026, the docs list these aliases:

| Alias | What it gives you |
| --- | --- |
| `default` | Clears your override and returns to the default for your account |
| `best` | The model `fable` resolves to where available, otherwise the same as `opus` |
| `fable` | Fable, for the hardest and longest-running tasks |
| `sonnet` | The latest Sonnet, for daily coding |
| `opus` | The latest Opus, for complex reasoning |
| `haiku` | Haiku, fast and light, for simple tasks |
| `sonnet[1m]`, `opus[1m]` | Those models with a 1M token context window |
| `opusplan` | Opus in plan mode, then Sonnet when it executes |

On the Anthropic API, `opus` maps to Opus 5.5, `sonnet` to Sonnet 5.5 and `haiku` to Haiku 5.5. On Amazon Bedrock and Google Cloud's Agent Platform, `sonnet` maps to Sonnet 4.5 and `haiku` to Haiku 4.5. On Microsoft Foundry, `opus` maps to Opus 4.6. To change what an alias points to, set `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL` or `ANTHROPIC_DEFAULT_HAIKU_MODEL`.

The docs say Fable is not the default on any plan. Pick it with `/model fable` or `claude --model fable`. Its usage may bill to usage credits, and interactive sessions show a consent prompt first.

## Change the effort level too

Effort is separate from the model. Set it with `/effort`, `claude --effort <level>` or the `CLAUDE_CODE_EFFORT_LEVEL` variable. Levels run from `low` to `max`, depending on the model. According to the docs, the default is `high` on most models and `medium` on Opus 5.5, Sonnet 5.5 and Haiku 5.5. Run `/effort auto` to clear a level you saved.

## Why your model keeps changing back

If a new session starts on a model you didn't pick, check these, all from the docs:

- A project or managed setting is overriding your `/model` choice. Project and managed settings reapply on each launch.
- `ANTHROPIC_MODEL` is exported in your shell and beats the settings file.
- Your organization restricts models with `availableModels`. A blocked choice is rejected in `/model`, or replaced at startup with a warning.
- You pressed `s` in the picker, so the choice was for one session only.
- Your user settings file is read-only, so `/model` could not save. The change applies now and is gone next session.

Run `/status` to see which settings files loaded, and `claude doctor` to list entries Claude Code rejected.

## Where to go next

If you are comparing tools before you commit to one, see [Claude Code vs Codex](https://claudegpt.si/news/claude-code-vs-codex). For what usage costs, see [Is Claude Code free](https://claudegpt.si/news/is-claude-code-free).

## Frequently asked questions

### How do I change the model in Claude Code?

Type /model in a session to open the picker, or /model sonnet to switch directly. To start on a model, run claude --model opus.

### How do I set a default model in Claude Code?

Add a model field to ~/.claude/settings.json, for example "model": "opus". Picking a model with Enter in the /model picker also saves it there.

### What does ANTHROPIC_MODEL do in Claude Code?

It sets the model for sessions launched with it and applies over the model key in any settings file. The --model flag overrides it.

### Why does Claude Code start on a different model than I picked?

A project or managed setting, an exported ANTHROPIC_MODEL, an organization allowlist, or a session-only choice made with s in the picker can all override it. Run /status to see which settings files loaded.

## Sources

- [Model configuration](https://code.claude.com/docs/en/model-config), Anthropic
- [Settings files and precedence](https://code.claude.com/docs/en/settings), Anthropic
- [CLI reference](https://code.claude.com/docs/en/cli-reference), Anthropic
- [Interactive mode](https://code.claude.com/docs/en/interactive-mode), Anthropic