diff --git a/prompts/session_9p.md b/prompts/session_9p.md
index 44c3935..5f4b0e8 100644
--- a/prompts/session_9p.md
+++ b/prompts/session_9p.md
@@ -59,6 +59,16 @@ Sessions live at `${OLLIE}/s/`. Each session is a directory; all operations are
 | `${OLLIE}/s/bbg`      | exec | Background query |
 | `${OLLIE}/s/cleanup`  | exec | Kill idle sessions |
 
+## Tool Registry
+
+Tools are scripts in `~/.config/ollie/tools/`. All tools are always discoverable; only loaded tools are callable.
+
+- **Discover** — `ollie-9p read s/${OLLIE_SESSION_ID}/tools` lists all available tools with descriptions.
+- **Load** — `echo <toolname> | ollie-9p write s/${OLLIE_SESSION_ID}/tools` promotes it to a native callable function.
+- **Check** — `ollie-9p read s/${OLLIE_SESSION_ID}/tools.loaded` shows which tools are active.
+
+Once loaded, a tool becomes a first-class function. Call it directly by name with JSON arguments matching its schema — no `call_tool` wrapper, no multiplexer.
+
 ### Session Directory (`${OLLIE}/s/{id}/`)
 
 | File | Mode | Purpose |