# Host \[Run the protocol yourself]

`@indexnetwork/protocol` is the canonical implementation. It knows no host: it
defines the interfaces, and you provide the infrastructure behind them.

```bash
npm install @indexnetwork/protocol
```

A host supplies persistence, an embedder, a cache, and request context; the
package supplies the graphs, the capability classes (`Intents`, `Networks`,
`Negotiations`), and the opportunity presenter. The package root is the only
import: `package.json` exports nothing else, so deep imports do not resolve.

The package builds its own models through OpenRouter from environment
variables, and a host cannot pass in its own:

| Variable | Purpose |
| --- | --- |
| `OPENROUTER_API_KEY` | Required. The package throws without it. |
| `CHAT_MODEL` | Optional override for the chat model. |
| `CHAT_REASONING_EFFORT` | Optional reasoning effort for the chat model. |

This page is a stub. The adapter list, graph factories, and wiring are in
[IMPLEMENTATION.md](https://github.com/indexnetwork/index/blob/dev/packages/protocol/IMPLEMENTATION.md).