# Anthropic
Anthropic uses API-key auth (`provider = "anthropic"`, `auth = "anthropic-api-key"`). For shared concepts such as credential storage and model selection, see [authentication and models](/authentication-and-models).
## Sign in
```text
/login anthropic
```
`/login anthropic` opens a masked API-key entry box in the [interactive TUI](/interactive-tui). Credentials are stored in the native OS credential store, not in config or transcripts.
## Sign out
```text
/logout anthropic
```
`/logout anthropic` deletes the stored Anthropic API key. If an environment override is still present, the provider stays available.
## Environment override
```bash
ANTHROPIC_API_KEY=...
```
Environment variables are CI/development escape hatches and override stored credentials. For normal interactive setup, prefer `/login`.
## Models
Anthropic can refresh its provider model list with `/refresh-model-list anthropic`. Switch to an Anthropic model with:
```text
/model anthropic/claude-sonnet-4-5
```
Or from the CLI, which also updates the persistent default:
```bash
rho --provider anthropic --auth anthropic-api-key --model claude-sonnet-4-5
```