> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mutual-dissent.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment Variables

> Environment variables for API keys and configuration

Environment variables are applied after `config.toml` and take precedence over file-based values.

## API Keys

| Variable             | Provider                        |
| -------------------- | ------------------------------- |
| `OPENROUTER_API_KEY` | OpenRouter (universal fallback) |
| `ANTHROPIC_API_KEY`  | Anthropic direct API            |
| `OPENAI_API_KEY`     | OpenAI direct API               |
| `GOOGLE_API_KEY`     | Google direct API               |
| `XAI_API_KEY`        | xAI direct API                  |
| `GROQ_API_KEY`       | Groq direct API                 |

## Precedence

For each provider, key resolution follows this order:

1. Environment variable (highest priority)
2. `[providers]` section in `~/.mutual-dissent/config.toml`
3. Empty string — request will fail at runtime

`OPENROUTER_API_KEY` also sets the top-level `api_key` field for backward compatibility.

## Minimal Setup

Only one key is required to run debates — `OPENROUTER_API_KEY` routes all five default models through OpenRouter:

```bash theme={null}
export OPENROUTER_API_KEY=sk-or-...
dissent ask "Your query here"
```

## Direct + Fallback

Set both an OpenRouter key and a direct vendor key. The router uses direct when available (in `auto` mode) and falls back to OpenRouter for models without a direct provider:

```bash theme={null}
export OPENROUTER_API_KEY=sk-or-...
export ANTHROPIC_API_KEY=sk-ant-...
```

With this setup, `claude-opus` and `claude` calls go directly to the Anthropic API; `gpt`, `gemini`, `grok`, and `nemotron` route through OpenRouter.

## Notes

* Direct provider implementations are currently available for Anthropic only. Other vendors route through OpenRouter regardless of key presence unless a direct provider is implemented.
* See [Routing](/config/routing) for per-model routing control.