Parameters

Talos can view and set ROS 2 parameters on any node in the graph. Parameters belong to individual nodes, so all parameter operations are addressed to a fully-qualified node name (for example /talos_agent).

How It Works

The agent acts as a parameter service client. For a requested node it creates short-lived clients to that node’s standard rcl_interfaces parameter services:

• <node>/list_parameters
• <node>/get_parameters
• <node>/set_parameters

These clients are serviced by the bridge node’s spinning executor. The agent waits briefly for the target services to become available, forwards the call, and converts the result into transport-agnostic protocol types so clients need no ROS 2 message definitions.

If the bridge node is not yet running, or the target node does not expose parameter services within the wait window, the agent returns an error rather than blocking indefinitely.

Values

Parameter values are carried as ParamValue, mirroring the variants of rcl_interfaces/msg/ParameterValue: Bool, Integer, Double, String, byte/bool/integer/double/string arrays, and NotSet for parameters that exist but have no value.

When setting a value from text (CLI argument or TUI edit field), the type is inferred:

• true / false → bool
• an integer literal → integer
• a number with a decimal point → double
• [ ... ] → an array (element type inferred from the contents)
• anything else → string (surrounding quotes are stripped)

Clients

The CLI exposes list-params, get-param, and set-param. See CLI.

The TUI Params tab lists graph nodes, loads a selected node’s parameters, and can edit a parameter value in place. See TUI.

Setting a parameter reports the node’s per-parameter result; a rejected change includes the reason supplied by the node.