docs: add feature monitoring page

docs/workflow/feature-monitoring.md

@@ -0,0 +1,43 @@
+---
+id: feature-monitoring
+title: Feature Monitoring
+slug: /feature-monitoring
+---
+
+How to view Grafana dashboards for a feature's health and enrollment metrics on the Feature Health Dashboard in Experimenter.
+
+## What Is Feature Monitoring?
+
+Feature monitoring provides a Grafana dashboard that tracks the health and usage metrics for a specific Nimbus feature config across all live and completed **rollouts**. It is powered by metric definitions in [metric-hub](https://github.com/mozilla/metric-hub/blob/main/featmon/firefox_desktop.toml).
+
+Unlike experiment-level monitoring (which tracks a single experiment), feature monitoring shows aggregate data across all rollouts for a feature, making it easy to spot regressions or unexpected changes in feature behaviour. Note that this is a **health monitoring** tool — it is not designed for statistical comparisons between branches or measuring experiment impact.
+
+## How to Access It
+
+1. Go to the [**Feature Health Dashboard**](https://experimenter.services.mozilla.com/nimbus/features/) in Experimenter.
+2. Select an application and a feature config from the dropdowns.
+3. If the feature has monitoring configured in metric-hub, a **Open Grafana Dashboard** button appears in the Feature Monitoring card.
+4. Click the button to open the dashboard in a new tab.
+
+## Why Is the Dashboard Not Available for My Feature?
+
+If you see the warning **"Grafana dashboard not available"**, it means the feature has not yet been added to the [metric-hub featmon config](https://github.com/mozilla/metric-hub/blob/main/featmon/firefox_desktop.toml).
+
+To enable feature monitoring for your feature, open a pull request against metric-hub adding your feature to `featmon/firefox_desktop.toml`. The file includes examples and comments explaining the required format.
+
+Once your PR is merged, the dashboard will become available for your feature in Experimenter after the next deploy.
+
+## What Metrics Are Available?
+
+The metrics shown in the Grafana dashboard depend on what is configured for your feature in metric-hub. Common metrics include:
+
+- **DAU (Daily Active Users)** — how many users are actively using the feature each day.
+- **Event counts** — specific interactions with the feature (clicks, impressions, etc.).
+- **Boolean / quantity metrics** — values reported from the feature's Glean metrics.
+
+Metrics are broken down by channel, locale, OS, and country where applicable.
+
+## Need Help?
+
+- To add your feature to metric-hub monitoring, see the [metric-hub featmon config](https://github.com/mozilla/metric-hub/blob/main/featmon/firefox_desktop.toml).
+- For questions about what metrics to add or how to interpret the dashboard, ask in [#ask-experimenter](https://mozilla.slack.com/archives/CF94YMZ2T).

sidebars.js

@@ -66,6 +66,7 @@ module.exports = {
         "workflow/risk-mitigation",
         "workflow/launching",
         "workflow/monitoring",
+        "workflow/feature-monitoring",
         "workflow/analyzing",
         "workflow/ending"
       ]