# Alerts

Lens can re-run a **saved question** on a schedule and notify you by **email** or **webhook** when a condition is met. Same field policy as the UI: protected cells stay `[redacted]`.

This follows the Metabase idea: alerts are for questions, destinations are configured first, then attached to the question. Slack is not included; use a webhook into Slack or any other receiver.

## Configure integrations

![Settings → Integrations](images/settings-integrations.png)

**Settings → Integrations** (`/lens/settings/integrations`).

### Email

One SMTP channel for the instance:

- Host, port, TLS, username, password, from address

Alerts then pick recipients per question. Sending mail needs `{:gen_smtp, "~> 1.2"}` in the **host** app (the dummy app already has it). You can also set app env:

```elixir
config :phoenix_lens,
  smtp: [
    host: "smtp.example.com",
    port: 587,
    tls: true,
    username: System.get_env("SMTP_USERNAME"),
    password: System.get_env("SMTP_PASSWORD"),
    from: "lens@example.com"
  ]
```

### Webhooks

Named HTTP endpoints. Each has a URL and optional Bearer token or API-key header.

When an alert fires, Lens POSTs JSON:

```json
{
  "type": "alert",
  "alert_id": 1,
  "alert_condition": "rows",
  "sent_at": "2026-09-07T12:00:00Z",
  "data": {
    "type": "question",
    "question_id": 5,
    "question_name": "Users (PII masked)",
    "raw_data": { "cols": ["id", "contact"], "rows": [[1, "[redacted]"]] },
    "num_rows": 1,
    "masked_columns": ["contact"]
  }
}
```

## Create an alert

1. Save the question.
2. Open it and click **Alert**.
3. Choose when to fire:
   - **any rows** / **no rows**
   - **above** / **below** a numeric goal (first numeric, non-masked cell)
4. Choose how often to check: 1m, 5m, 15m, hourly, 6h, daily.
5. Add email addresses and/or webhooks.
6. Optionally **Only send once, then disable**.

**Send now** runs the question immediately and delivers if the condition is met.

A scheduler in the Lens OTP app checks due alerts about every 30 seconds. Audit actor is `alert:<id>`.

## MCP

`list_integrations`, `save_email_integration`, `add_webhook`, `remove_webhook`, `list_alerts`, `create_alert`, `delete_alert`, `run_alert`.