List all ROS topics currently known to the robot, with message types.

Takes no arguments. Returns {"topics": [{"name": "/scan", "type": "sensor_msgs/msg/LaserScan"}, ...]}. Call this first to discover what the robot exposes before subscribing or publishing.

List all ROS nodes currently running on the robot.

Takes no arguments. Returns {"nodes": ["/talker", "/rosapi", ...]}. Useful to check whether an expected driver or controller is up.

List all ROS services currently available on the robot.

Takes no arguments. Returns {"services": ["/reset_odometry", ...]}. Use before call_service to find the exact service name.

Read live data from a topic: subscribe, collect up to count messages (or until timeout seconds elapse), then unsubscribe.

Args: topic: Topic name including leading slash, e.g. "/scan" or "/odom". count: How many messages to collect (default 1, clamped to at most 100). Use more to observe a value changing over time. timeout: Max seconds to wait (default 5.0, clamped to at most 60.0). The tool never blocks longer than this, even on a silent topic. msg_type: Optional full message type, e.g. "sensor_msgs/msg/LaserScan". Usually omit it; rosbridge resolves the type of existing topics.

Returns {"topic", "requested", "received", "messages": [...], "timed_out", "timeout_s"}. If "timed_out" is true, nothing (or not enough) was published within the timeout — the topic may be silent, misspelled, or not exist. If the rosbridge connection drops mid-collection, the tool returns immediately with {"error", "connection_lost": true} instead of waiting out the timeout.

Publish a JSON message to a ROS topic (advertises the topic first).

CAUTION: this can move a real robot. Rejected when ROSBRIDGE_MCP_READONLY is set. Prefer reading relevant sensor topics (e.g. /scan, /odom) before commanding motion, and publish zero velocity to stop.

Args: topic: Target topic, e.g. "/cmd_vel". msg_type: Full ROS 2 message type with the "/msg/" segment, e.g. "geometry_msgs/msg/Twist" or "std_msgs/msg/String". message: JSON object whose fields match the message definition, e.g. {"linear": {"x": 0.1, "y": 0.0, "z": 0.0}, "angular": {"x": 0.0, "y": 0.0, "z": 0.2}} for a Twist. Omitted fields default to zero/empty on the ROS side.

Returns {"published": true, "topic": ..., "type": ...} on success. The tool briefly waits for rosbridge 'status' errors after publishing; if rosbridge rejected the message (e.g. wrong msg_type), the result includes "rosbridge_warnings" — treat those as the publish having failed.

Call any ROS service with JSON args and return the response values.

Rejected when ROSBRIDGE_MCP_READONLY is set, unless the service is on the fixed allowlist of known read-only /rosapi introspection services (topics, nodes, services, *_type, *_details, get_param, get_time, ...).

Args: service: Full service name, e.g. "/rosapi/topic_type" or "/reset_odometry". Discover names with list_services. args: JSON object matching the service request definition, e.g. {"topic": "/scan"} for /rosapi/topic_type. Default {}. timeout: Max seconds to wait for the response (default 10.0).

Returns {"service", "success": true, "values": {...}} on success, or {"service", "success": false, "error": "..."} on failure/timeout (with any related rosbridge status errors under "rosbridge_status").

Send a goal to a ROS 2 action server via rosbridge.

CAUTION: actions typically make the robot move (navigation, arm motion). Rejected when ROSBRIDGE_MCP_READONLY is set.

Args: action_name: Action name, e.g. "/navigate_to_pose". action_type: Full action type with the "/action/" segment, e.g. "nav2_msgs/action/NavigateToPose". goal: JSON object matching the action's goal definition. Default {}. timeout: Max seconds to wait for the result when wait_for_result is true (default 30.0, clamped to at most 120.0). wait_for_result: If true (default), block until the action finishes and return its result. If false, return the goal_id immediately — use cancel_action_goal with that id to stop the goal later.

Returns, when waiting: {"action", "goal_id", "success", "status", "status_text" (succeeded/aborted/canceled/...), "values" (result fields), "last_feedback" (most recent feedback values, or null)}. When not waiting: {"action", "goal_id", "result_pending": true}.

Requires rosbridge_suite with ROS 2 action support (ops send_action_goal / cancel_action_goal). Against an older rosbridge the tool detects the rejected operation (via rosbridge status errors, or timeout as fallback) and returns an error advising to upgrade rosbridge_suite on the robot.

Cancel a previously sent ROS 2 action goal.

Rejected when ROSBRIDGE_MCP_READONLY is set.

Args: action_name: The action the goal was sent to, e.g. "/navigate_to_pose". goal_id: The goal_id returned by send_action_goal.

Returns {"cancel_sent": true, "action", "goal_id"}. The cancellation outcome (status "canceled") is reported by the action server via the goal's result. Requires rosbridge_suite with ROS 2 action support; on an older rosbridge the tool returns an error advising an upgrade.

Snapshot the robot's TF (coordinate transform) tree.

Subscribes briefly to /tf and /tf_static, merges every transform seen into a parent→child frame tree. Read-only — works in readonly mode. Useful for spatial reasoning: which frames exist (map, odom, base_link, camera, gripper, ...) and how they are connected.

Args: timeout: Seconds to listen for transforms (default 2.0, clamped to at most 10.0). Static transforms are latched and arrive immediately; dynamic ones need the robot to be publishing.

Returns {"frame_count", "frames": {child_frame: {"parent", "translation": {x,y,z}, "rotation": {x,y,z,w}, "source": "static"|"dynamic"}}, "tree": {parent: [children...]}, "roots": [frames with no parent seen]}. An empty tree usually means nothing publishes /tf on this robot (or the listen window was too short).

Grab one frame from a camera topic, for vision-capable models.

Read-only — works in readonly mode. Subscribes to topic, waits for one sensor_msgs/msg/CompressedImage (preferred) or sensor_msgs/msg/Image (raw) message, and returns the frame as base64. This is the bridge for VLM / vision-language-action workflows: the model can literally look through the robot's camera before deciding how to act.

Args: topic: Camera topic, e.g. "/camera/image_raw/compressed". Prefer a compressed topic — raw images are large and may exceed the size limit below. timeout: Max seconds to wait for a frame (default 5.0, clamped to at most 30.0).

Returns {"topic", "format" (e.g. "jpeg"), "data_base64", "size_bytes"}, plus "width"/"height"/"encoding" for raw images. Frames larger than 4 MB are not returned: the tool responds with an error suggesting a CompressedImage topic instead (raw metadata is still included).

Report the current rosbridge connection status and readonly mode.

Takes no arguments. Returns {"url", "connected", "connected_since_unix", "active_subscriptions", "pending_service_calls", "readonly"}. The connection is opened lazily, so "connected" is false until another tool has been used. Check this first when other tools report errors.