diff --git a/src/fabledassistant/mcp/server.py b/src/fabledassistant/mcp/server.py
index e360897..e3cd3ae 100644
--- a/src/fabledassistant/mcp/server.py
+++ b/src/fabledassistant/mcp/server.py
@@ -122,6 +122,13 @@ X process" or otherwise references a saved process, call list_processes() /
 get_process(name) and follow the returned prompt verbatim, including any
 "clarify first" steps it contains. Author a new one with create_process(title,
 body); edit with update_process.
+
+When you are developing Scribe itself (not just using it as a data store),
+honor the multi-user sharing ACL: every read or mutation of user data must
+scope by owner + direct shares + group shares through services/access.py
+(can_read_* / can_write_* / can_admin_*) — never assume a single operator. An
+unscoped query (a fetch-by-id with no ownership check) is a cross-user data
+leak; "works for one user" is not done.
 """