Identify current ROS 2 controllers, viewing their state and permissible types. Determine which controllers the safety policy permits you to switch during operation.
ros2_control controllers with their type and state, plus which ones the policy lets you switch.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| switchable | Yes | Controllers the policy allows to be (de)activated | |
| controllers | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered. The description's one added signal is the policy gate on which controllers may be switched, which is useful context for downstream switching, but nothing about cost, freshness, or failure mode is disclosed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
It is short with no filler, but it is a noun-phrase fragment lacking a verb, so the key action is only recoverable from the tool name. Every word earns its place; the structure is the weakness, not the length.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With an output schema present, the returned fields (type, state, switch permissions) need not be spelled out, and with 0 params the schema carries no burden. The remaining gap is guidance on sequencing relative to switch_controllers, which is left to inference.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The only thing it could clarify is whether the listing is filtered by namespace or policy, which it partially implies but does not define.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names the specific resource (ros2_control controllers) and what is returned about them: type, state, and policy-permitted switching. A fragment rather than a verb-led sentence, but an agent can still tell this is a read/list of controllers and infer it differs from switch_controllers.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is only implied: 'which ones the policy lets you switch' hints this is the discovery step before switch_controllers, but there is no explicit 'use before switching' or 'when not to use'. No alternatives or exclusions are named.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.