get_mass_properties

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It lists the output values and their units, but does not communicate whether this is a read-only operation, whether it requires a loaded model, whether it depends on a rebuild, or what happens if no part is open. These are important preconditions that the description omits.

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, compact sentence that lists the outputs in a logical order. It is immediately front-loaded with the action and the main resource, and every element (units and property names) adds value. No superfluous words or filler are present.

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 zero-parameter tool with no output schema and no annotations, the description should at least hint at preconditions (e.g., 'on the current model') and possibly note that this is a combined query replacing multiple calls. It does specify the output units and properties, but misses guidance on when it is appropriate to call (e.g., after a rebuild) and how it compares to the get_bounding_box sibling. This is sufficient for a trivial command but not fully complete.

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?

The tool has zero parameters, so there is nothing to document beyond the already-empty schema. The description adds no parameter semantics, but the baseline for 0 parameters is 4, which is appropriate since the lack of parameters is self-evident and no further clarification is needed.

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 a resource ('mass properties') and enumerates the exact quantities returned (volume, mass, surface area, center of mass, bounding box). It is clearly distinguishable from siblings like get_bounding_box, which returns only the bounding box, so the purpose is precise and unambiguous.

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 gives no guidance on when to use this tool versus alternatives. It does not mention that it operates on the current part or assembly, nor does it reference the more specialized get_bounding_box or other related getters. An agent has to infer the appropriate context, which is a significant gap for a simple tool.

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