# Connect a model

One API key in the environment connects Anthropic or OpenAI, and your key never reaches a settings file, a log, or the session record.

Eva talks to Anthropic and OpenAI, so a key is the whole setup.

```bash
export ANTHROPIC_API_KEY=sk-ant-...
eva
```

That is it. There is no login step, no config file to edit, and no account.
For OpenAI models, export `OPENAI_API_KEY` instead and pick one:

```bash
export OPENAI_API_KEY=sk-...
eva --model openai/gpt-5.4
```

A local model behind Ollama, or any OpenAI-compatible endpoint, is one config
entry away — [providers](/configure/providers) shows it.

## Where your key goes, and where it does not

**Your key never reaches a settings file, a log, or the session record.** Eva
reads it from the environment at the moment it opens a request and holds it
nowhere else.

This matters because a session record is a file on your disk that you may
share, copy into an issue, or hand to another tool. It never contains a
credential.

## Choose a different model

Set it for one run with a flag:

```bash
eva --model anthropic/claude-sonnet-5
```

Or set it inside a session with a command:

```
/model anthropic/claude-sonnet-5
```

`/model` with no argument shows the current model and offers the ones Eva
knows about. See [models](/configure/models).

## What Eva costs

Eva reports what a provider says a request cost, and marks an estimate as an
estimate. [Cost and usage](/use/cost) explains the difference, and why Eva
refuses to guess.

Next: [your first run](/first-run).


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This page as HTML: https://docs.evafactory.co/connect-a-model
Every page as one markdown index: https://docs.evafactory.co/llms.txt