ros2-mcp-server

get_pid_state

Read current Kp, Ki, and Kd gains from a ROS2 PID controller node, including safety bounds, to verify tuning parameters.

Instructions

Read current Kp, Ki, Kd gains from a PID controller node, with safety bounds.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "node_name": "<node_name>"
    },
    "name": "get_pid_state"
  }
}

Input Schema

Name	Required	Default
`kd_param`	No	kd
`ki_param`	No	ki
`kp_param`	No	kp
`node_name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.1.0Aug 11, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full responsibility for behavioral disclosure. It only says 'Read' which implies non-mutating, but it does not explain what 'with safety bounds' entails, what happens if the node or parameters are missing, or whether any state is changed. The ambiguity around 'safety bounds' leaves significant gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no wasted words. However, the phrase 'with safety bounds' is vague and may add confusion rather than clarity, preventing a perfect score.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is relatively simple but has four parameters and no output schema. The description does not mention return values, error behavior, or distinguish from similar tools like get_parameter. Given the complexity and lack of annotations/schema descriptions, it is far from complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage and the tool description does not clarify how the four parameters are used. It mentions Kp, Ki, Kd but does not map them to the kp_param, ki_param, kd_param fields nor explain what node_name is for. The description fails to compensate for the lack of schema explanations.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Read') and the target resource ('Kp, Ki, Kd gains from a PID controller node'), making it easy to identify the tool's purpose. It distinguishes itself from generic tools like get_parameter by being specific to PID gains.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives. It does not mention that get_parameter could be used for single gains or that tune_pid is for adjusting gains, so the agent has no context for choosing this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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