When someone sends a DM to the bot and isn't on the allowlist — whether it's a new user or an existing user on a new channel — nanobot automatically replies with a **pairing code** (like `ABCD-EFGH`) that expires in 10 minutes. To grant them access:
```text
/pairing approve ABCD-EFGH
```
To see who's waiting, use `/pairing`. To remove someone later, use `/pairing revoke <user_id>` — you can find user IDs in the `/pairing list` output.
See [Configuration: Pairing](./configuration.md#pairing) for the full setup guide.
The response shows the current model, the current preset, and the available preset names. Named presets come from the top-level `modelPresets` config and are the recommended way to configure model choices. `default` is always available and represents the model settings from direct `agents.defaults.*` fields.
Preset names come from the top-level `modelPresets` config. Switching is runtime-only: it does not rewrite `config.json`, and an in-progress turn keeps using the model it started with. See [Configuration: Model presets](./configuration.md#model-presets) for setup details.
Periodic tasks are driven by `HEARTBEAT.md` in your workspace (`~/.nanobot/workspace/HEARTBEAT.md`). When `nanobot gateway` starts, it registers a protected heartbeat cron job by default. Every 30 minutes, that job checks the file; if it finds tasks under `## Active Tasks`, the agent executes them and delivers results to your most recently active chat channel. If there are no active tasks, the heartbeat is skipped silently.
The agent can also manage this file itself — ask it to "add a periodic task" and it will update `HEARTBEAT.md` for you. Completed tasks should be deleted from the file, not moved to another section.
You can change the interval or disable the built-in heartbeat in `~/.nanobot/config.json`:
```json
{
"gateway":{
"heartbeat":{
"enabled":true,
"intervalS":1800
}
}
}
```
The heartbeat job is visible in `cron(action="list")` as `heartbeat`, but it is system-managed and cannot be removed with the `cron` tool. To stop it, set `gateway.heartbeat.enabled` to `false` and restart the gateway.
> **Note:** The gateway must be running (`nanobot gateway`) and you must have chatted with the bot at least once so it knows which channel to deliver to.
