diff --git a/.codex/hooks.json b/.codex/hooks.json
index 5374b0e628..8baaa5a8e2 100644
--- a/.codex/hooks.json
+++ b/.codex/hooks.json
@@ -5,7 +5,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "./bin/brew lgtm >&2 && printf '{\"continue\":true}'",
+            "command": ".codex/hooks/brew-lgtm-stop.sh",
             "timeout": 360
           }
         ]
diff --git a/.codex/hooks/brew-lgtm-stop.sh b/.codex/hooks/brew-lgtm-stop.sh
new file mode 100755
index 0000000000..9bc8522484
--- /dev/null
+++ b/.codex/hooks/brew-lgtm-stop.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+cd "$(dirname "$0")/../.." || {
+  printf '%s\n' '{"decision":"block","reason":"Failed to cd to the repository root before running ./bin/brew lgtm."}'
+  exit 0
+}
+
+if ./bin/brew lgtm >&2
+then
+  printf '%s\n' '{"continue":true}'
+else
+  printf '%s\n' '{"decision":"block","reason":"./bin/brew lgtm failed; review the output above and fix it before stopping."}'
+fi