diff --git a/README.md b/README.md
index 9d7c223..d97b9f4 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,8 @@ Workbench is an [MCP server](https://modelcontextprotocol.io). Once configured,
 
 The AI generates all content — HTML, CSS, JavaScript. Workbench is just the plumbing.
 
+Pages can write back too: `fetch('log', {method: 'POST', body: JSON.stringify({entry, data})})` appends to the session log (e.g. meter readings typed on a phone), and `session.jsonl` / `state.json` are readable from the page, so any device opens to the same state.
+
 ### Server Persistence
 
 Workbench servers survive AI CLI restarts. If you restart your AI and it calls `workbench_scaffold` again, it detects the existing running server and reattaches — no duplicates, no lost connections. The browser stays connected throughout.