docs(ai-agents): introduce pinned context

guides/ai-agents.mdx

@@ -54,6 +54,7 @@ This guide covers everything you need to know about AI agents in Lightdash:
 ## Key features
 
 - **Natural language queries** - Ask questions in plain English and get instant answers
+- **Ask from a chart or dashboard** - Launch a conversation with the chart or dashboard you're viewing already pinned as context
 - **Automatic visualizations** - Get charts, tables, and dashboards generated based on your questions
 - **Slack integration** - Collaborate with your team directly in Slack channels
 - **Memory and learning** - Agents remember corrections and improve over time

guides/ai-agents/using-ai-agents.mdx

@@ -20,6 +20,35 @@ As mentioned earlier, Lightdash agents use the **semantic layer** defined in you
 This ensures that the AI generates accurate queries and visualizations based on your specific data context.
 So, *when an Agent generates an answer, the output is a semantic query, **not SQL!*** This means that you can easily swap between the conversational AI interface and the standard Lightdash exploration experience.
 
+## Asking about a chart or dashboard
+
+You can launch an AI conversation with a chart or dashboard pre-loaded as context. From the resource's `⋯` menu, click **Ask AI Agent**.
+
+This opens a new tab on the new-thread page for your default agent. The chart or dashboard appears as a **pinned context card** above the input, and the agent treats it as the subject of the conversation.
+
+<Frame>
+  <img
+    src="/images/guides/ai-agents/ask-ai-agent-from-chart.png"
+    alt="Ask AI Agent menu item on a saved chart"
+  />
+</Frame>
+
+### Pinned context
+
+- The pinned card stays visible above your message in the thread, so anyone reading later can tell what was being discussed.
+- Click the pinned card to open the chart or dashboard in a new tab.
+- The pinned context persists across follow-up messages — *"now break it down by region"* still refers to the originally pinned chart.
+
+### What you can ask
+
+When you pin a saved chart, the agent can read its actual data (subject to your [data access setting](/guides/ai-agents/data-access)). It honors the chart's saved filters, sorts, and custom metrics, so you can ask:
+
+- *"Why is this trending up?"*
+- *"Are there outliers in this chart?"*
+- *"Compare this chart's last 30 days to the previous period."*
+
+If your agent has data access disabled, pinning still works — the agent sees the chart's structure (name, dimensions, metrics) but no row values are sent to the underlying LLM.
+
 ## Example use cases
 
 ### Advanced visualizations with window functions