diff --git a/hooks/hooks.json b/hooks/hooks.json
index 04775a2..3567572 100644
--- a/hooks/hooks.json
+++ b/hooks/hooks.json
@@ -42,8 +42,8 @@
         "matcher": "",
         "hooks": [
           {
-            "type": "prompt",
-            "prompt": "If you read or modified any wiki pages during this session, update wiki/hot.md with a brief summary of what changed (under 500 words). Use the hot cache format: Last Updated, Key Recent Facts, Recent Changes, Active Threads. Keep it factual. Overwrite the file completely. It is a cache, not a journal."
+            "type": "command",
+            "command": "cd \"$PWD\" && [ -d wiki ] && [ -d .git ] && git diff --name-only HEAD 2>/dev/null | grep -q '^wiki/' && echo 'WIKI_CHANGED: Wiki pages were modified this session. Please update wiki/hot.md with a brief summary of what changed (under 500 words). Use the hot cache format: Last Updated, Key Recent Facts, Recent Changes, Active Threads. Keep it factual. Overwrite the file completely. It is a cache, not a journal.' || true"
           }
         ]
       }