ros_install_info

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

With no annotations, the description carries the full burden and does well: it names what is returned (installed flag, distro list with paths, PATH availability, the distro the MCP tools will use, ROS env vars) and clarifies it works without ROS installed. It stops short of an explicit read-only/no-side-effect statement, which would complete the safety profile.

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?

Front-loaded with the purpose, then clearly labeled '何时用' and '返回' sections. It is slightly verbose but every line carries meaning; no filler or repetition.

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?

No output schema exists, and the description compensates by enumerating the return fields and the preflight ordering role. For a zero-parameter detection tool with no annotations, nothing an agent needs to call it correctly is missing.

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, which warrants the baseline 4; there are no inputs to disambiguate, and the description correctly spends no words on parameters.

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?

States a specific verb+resource: detect whether ROS2 is installed and which distros are present, plus that it runs without ROS installed. An agent can distinguish this preflight probe from the sibling inspection tools (list_nodes, list_topics, etc.) without opening any schema.

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?

The '何时用' block gives an explicit triggering condition (uncertain whether ROS exists, which version, whether tools can run) and an explicit ordering rule — call this first, then decide which inspection tools to use. So it directly routes the agent relative to siblings.

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