Annotations

Annotations enable you to add written notes to a particular day or time on all your insights and dashboards so you can see how changes or incidents impact your metrics.

You can use annotations to mark things like feature updates, version releases, and marketing campaigns, which adds helpful context when you're looking into what might have caused a change in your metrics.

Why Annotations are useful

The chart below shows a large spike in website traffic, which has been annotated to explain why that spike occurs. Annotations can be viewed by hovering over them.

Annotations can be written after the fact, which makes them useful for future reference, or before an event if you want to analyze the future impact of a particular marketing initiative, for example.

Creating an Annotation

When editing a chart in Trends, Sessions or in a Dashboard, hover your cursor over the dates at the bottom of the chart to reveal a button with a + symbol. Clicking it will then open up a modal where you can create your Annotation, as well as choose to have it specifically for the current chart or all of your charts.

With your annotation created, it will now be available at the bottom of your chart, and you can also view all of your existing annotations in /data-management/annotations.

Managing annotations via AI agents

You can manage annotations using AI coding assistants like Cursor, Claude Code, VS Code, or any tool that supports the Model Context Protocol (MCP).

With the PostHog MCP server connected, you can ask your AI agent to:

• Create annotations to mark deployments, releases, or incidents
• List existing annotations to review what's been marked
• Retrieve, update, or delete specific annotations

For example, you might prompt: "Create an annotation for today saying 'Deployed checkout v2.0'" and the agent will create it in your project.

This is useful for marking deployments directly from your development workflow without switching to the PostHog app.