TRIGGER when the user: writes or reviews ROS 2 nodes (rclcpp/rclpy), creates packages (colcon/ament), edits launch files (.launch.py), configures QoS or DDS, writes URDF/xacro, implements ros2_control hardware interfaces or controllers, sets up Nav2/MoveIt 2 pipelines, processes sensor data (camera/LiDAR/PCL), works with Gazebo/Isaac Sim, configures SROS2 security, develops micro-ROS firmware, manages multi-robot fleets (Open-RMF), debugs with ros2 doctor/rosbag2, deploys via Docker/cross-compilation, or migrates from ROS 1. DO NOT TRIGGER for general C++/Python questions unrelated to ROS 2, non-robotics middleware, or web/mobile development tasks.