Alerts now warn you before a monthly quota runs out

The Alerts page now covers your monthly quotas, one alert each for conversations, pages read and generations. They concern the whole organization, not a site.

• Warning when a month's usage reaches 80% of the quota, rounded up.
• Critical when usage reaches the quota and that stops the service.
• Closed when the quota is raised, or at the start of the new month (00:00 UTC). A new alert opens if the new month is already past 80%.

The count on the sidebar's Alerts entry is red if any open alert is critical and amber when all of them are warnings. Its accessible name now says how many are critical. On a narrow screen the dot on the sidebar button follows the same colours.

A quota alert has a View billing button, shown only to members who may view billing. It sends no email of its own: the 80% and 100% quota emails are unchanged.

The REST API (GET /api/v1/alerts) and the MCP list_alerts tool return these alerts too, with their kind and severity. A quota alert has no site and no usage figure.