diff --git a/packages/web/src/content/docs/tui.mdx b/packages/web/src/content/docs/tui.mdx
index a92da6a022..013dc4a6ba 100644
--- a/packages/web/src/content/docs/tui.mdx
+++ b/packages/web/src/content/docs/tui.mdx
@@ -27,6 +27,26 @@ Give me a quick summary of the codebase.
 
 ---
 
+## Session context
+
+OpenCode tracks token usage and cost for each session. You can open the **Context** tab from the context indicator in the session header.
+
+- Hover the indicator to see a quick tooltip (tokens, % usage, cost).
+- Click it to open the **Context** tab.
+
+The **Context** tab includes:
+
+- Provider/model details and the model's context limit
+- Token totals (input/output/reasoning/cache) plus an approximate breakdown
+- The latest system prompt (if one was set)
+- Raw message JSON for debugging
+
+:::note
+The breakdown is an estimate; providers tokenize content differently.
+:::
+
+---
+
 ## File references
 
 You can reference files in your messages using `@`. This does a fuzzy file search in the current working directory.