ros2-mcp-server

set_parameter

Update a parameter on a running ROS2 node, with sandboxing that permits only allowlisted parameters in SAFE_WRITE mode.

Instructions

Dynamically update a parameter on a running ROS2 node. Sandboxed — only allowlisted parameters can be modified in SAFE_WRITE mode.

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>",
      "param_name": "<param_name>",
      "value": "<value>"
    },
    "name": "set_parameter"
  }
}

Input Schema

Name	Required	Description
`value`	Yes	New value — float, int, string, or bool
`node_name`	Yes
`param_name`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.1.0Aug 11, 2026

TDQS

A4/5.0

Behavior4/5

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

Since no annotations are provided, the description carries the full burden. It explicitly discloses that the tool is a mutation ('update') and introduces the sandbox/allowlist restriction, which is important safety context. It does not detail error handling or reversibility, but the core behavioral traits are covered.

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

Conciseness5/5

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

Two sentences, front-loaded with the primary action, and every word adds value. The safety constraint is included without unnecessary padding.

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

Completeness3/5

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

The description captures the core purpose and safety restriction, but with no output schema and no parameter details, the agent lacks information about return values, error conditions, or how to discover allowlisted parameters. It is adequate but not 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?

Schema description coverage is only 33%, and the description adds no parameter-level details. The value field is documented in the schema, but node_name and param_name are left without explanations. The description does not compensate for the low coverage.

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 tool's function with a specific verb ('update') and resource ('parameter on a running ROS2 node'). It distinguishes from sibling tools like get_parameter (read) and tune_pid (specialized tuning).

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

Usage Guidelines4/5

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

Provides clear contextual constraints: the tool operates on running ROS2 nodes and only allowlisted parameters in SAFE_WRITE mode. However, it does not explicitly mention alternatives or exclusions (e.g., when to prefer tune_pid or get_parameter).

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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