Tool reference

Every tool returns a single JSON object (as a text content block). The connect argument is optional everywhere and resolves to connect → ZENOH_CONNECT → tcp/localhost:7447.

zenoh_info

Connect to a router and confirm reachability.

Arguments

Name	Type	Required	Description
connect	string	no	Router endpoint.

Returns

{
  "connected": true,
  "endpoint": "tcp/192.0.2.10:7447",
  "session_zid": "3e68be0d2e4cfd72e6cdc6fe26cc998c",
  "zenoh_version": "1.8.0",
  "router_admin_keys": ["@/<zid>/router"]
}

zenoh_get

Send a Zenoh GET (query) for a selector and return replies. Works for data queryables and for the router admin space (@/** → topology, plugins, transports). CDR replies are decoded.

Arguments

Name	Type	Required	Default	Description
selector	string	yes	—	Selector / key expression, e.g. @/** or demo/**.
connect	string	no	—	Router endpoint.
timeout_ms	integer	no	3000 (≤30000)	Max time to wait for replies.

Returns

{
  "selector": "@/**",
  "endpoint": "tcp/192.0.2.10:7447",
  "count": 1,
  "replies": [
    { "key": "@/<zid>/router", "ros_type": null, "kind": "Put", "value": { "...": "..." } }
  ]
}

A reply that carries a query error becomes { "error": "<message>" }.

zenoh_put

Publish a UTF-8 value to a key expression. Useful for poking subscribers and queryables. Mutates network state.

Arguments

Name	Type	Required	Description
key	string	yes	Key expression to publish to, e.g. demo/test.
value	string	yes	UTF-8 payload.
connect	string	no	Router endpoint.

Returns

{ "ok": true, "key": "demo/test", "bytes": 11, "endpoint": "tcp/192.0.2.10:7447" }

zenoh_subscribe

Subscribe to a key expression for a few seconds and return the samples received, with ROS2 CDR payloads decoded to JSON. The primary tool for “what is being published on this topic right now?”.

Arguments

Name	Type	Required	Default	Description
key	string	no	**	Key expression to subscribe to.
connect	string	no	—	Router endpoint.
duration_secs	integer	no	3 (1–30)	How long to collect samples.
max_samples	integer	no	100 (1–2000)	Stop early after this many samples.

Returns

{
  "key": "0/kuka/joint_states/**",
  "endpoint": "tcp/192.0.2.10:7447",
  "duration_secs": 2,
  "count": 1,
  "truncated": true,
  "samples": [
    {
      "key": "0/kuka/joint_states",
      "ros_type": "sensor_msgs/JointState",
      "kind": "Put",
      "value": {
        "header": { "frame_id": "kuka_base", "stamp": { "sec": 1780658057, "nanosec": 215979475 } },
        "name": ["a1", "a2", "a3", "a4", "a5", "a6"],
        "position": [-0.140, -1.582, 1.779, 0.135, 0.809, -0.248],
        "velocity": [],
        "effort": []
      }
    }
  ]
}

truncated is true when collection stopped because max_samples was reached rather than the duration elapsing.

zenoh_list_keys

Discover topics: listen briefly on a key expression and return the distinct keys seen, each with its inferred ROS2 type and a sample count. Like ros2 topic list for the Zenoh network.

Arguments

Name	Type	Required	Default	Description
key	string	no	**	Key expression to sweep.
connect	string	no	—	Router endpoint.
duration_secs	integer	no	3 (1–30)	How long to listen before reporting.

Returns

{
  "endpoint": "tcp/192.0.2.10:7447",
  "duration_secs": 3,
  "distinct_keys": 2,
  "keys": [
    { "key": "0/chatter", "ros_type": "std_msgs/String", "samples": 3 },
    { "key": "0/kuka/pose", "ros_type": "geometry_msgs/PoseStamped", "samples": 83 }
  ]
}