diff --git a/lib/hooks.sh b/lib/hooks.sh
index 95400c3..a39f637 100644
--- a/lib/hooks.sh
+++ b/lib/hooks.sh
@@ -7,9 +7,17 @@
 #
 # Without this hook, claude would exit to an interactive prompt instead of
 # returning control to the loop script.
+#
+# IMPORTANT: The hook is scoped to only fire inside the agent-loop tmux session.
+# Without this guard, ANY Claude Code session opened in the same project directory
+# would pick up the hook and kill its own parent shell on exit.
 
 SETTINGS_FILE="${PROJECT_ROOT}/.claude/settings.local.json"
 
+# The hook command checks we're inside the agent-loop tmux session before killing.
+# This prevents the hook from affecting other CC sessions open in the same project.
+HOOK_COMMAND='tmux display-message -p "#{session_name}" 2>/dev/null | grep -q "^agent-loop$" && kill -INT $PPID || true'
+
 install_hooks() {
     if [ ! -f "$SETTINGS_FILE" ]; then
         mkdir -p "$(dirname "$SETTINGS_FILE")"
@@ -17,14 +25,16 @@ install_hooks() {
     fi
 
     if command -v jq &>/dev/null; then
-        jq '.hooks.Stop = [{"matcher": "", "hooks": [{"type": "command", "command": "kill -INT $PPID || true"}]}]' \
+        jq --arg cmd "$HOOK_COMMAND" \
+            '.hooks.Stop = [{"matcher": "", "hooks": [{"type": "command", "command": $cmd}]}]' \
             "$SETTINGS_FILE" > "${SETTINGS_FILE}.tmp" && mv "${SETTINGS_FILE}.tmp" "$SETTINGS_FILE"
     else
-        LOOP_SETTINGS="$SETTINGS_FILE" python3 -c "
+        LOOP_HOOK_CMD="$HOOK_COMMAND" LOOP_SETTINGS="$SETTINGS_FILE" python3 -c "
 import json, os
 p = os.environ['LOOP_SETTINGS']
+cmd = os.environ['LOOP_HOOK_CMD']
 s = json.load(open(p)) if os.path.exists(p) else {}
-s.setdefault('hooks', {})['Stop'] = [{'matcher': '', 'hooks': [{'type': 'command', 'command': 'kill -INT \$PPID || true'}]}]
+s.setdefault('hooks', {})['Stop'] = [{'matcher': '', 'hooks': [{'type': 'command', 'command': cmd}]}]
 json.dump(s, open(p, 'w'), indent=2)
 "
     fi