Get mass properties

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

Annotations declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds that it returns volume, mass, centroid, and inertia, which is useful. It does not disclose details like units, coordinate frame, or whether it returns per-body or aggregate values, but the read-only safety profile is already covered by annotations.

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?

The description is a single concise sentence that front-loads the key output quantities. It earns its place with no wasted words, though it could add a brief note about the sibling tool without much cost.

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?

For a read-only query tool with 100% schema coverage and no output schema, the description is adequate but not complete. It does not mention units, whether the result is per-body or aggregate, or how it differs from onshape_assembly_mass_properties. An agent could call it correctly, but might misinterpret the scope of the returned values.

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?

Schema description coverage is 100%, so the schema already documents all four parameters. The description adds no parameter-specific meaning beyond what the schema provides. Baseline 3 is appropriate.

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 states a specific verb ('Get') and resource ('mass properties') and lists the computed quantities (Volume, mass, centroid and inertia) for the Part Studio's bodies. It is clear enough to distinguish from the sibling onshape_assembly_mass_properties, though it does not explicitly name that sibling.

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 description implies usage: call it when you need mass properties of Part Studio bodies. It does not explicitly state when to use this versus onshape_assembly_mass_properties, nor does it mention any prerequisites (e.g., the part studio must have bodies). The context is clear but exclusions/alternatives are not stated.

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