sw_mass_properties

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuine value by disclosing the returned quantities and their units (mm / kg), but says nothing about scope (whole document vs. selected bodies) or failure behavior when no document is active.

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?

One compact sentence listing outputs and units with zero filler. Everything is front-loaded, though it reads as a fragment rather than a statement of action.

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?

With no output schema, the description must carry return-value information, and it does list the fields and units. However it omits the document/body scope and any prerequisite (e.g., a rebuilt or up-to-date model), leaving gaps for a computation tool.

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 coverage is 100%: the single 'doc' parameter is fully documented in the schema as a title or path defaulting to the active document. The description adds nothing beyond that, so baseline 3 applies.

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 enumerates exactly what the tool reports: mass, volume, area, centre of mass, principal moments, and bounding box. That makes the resource unambiguous even though it is a bare noun phrase with no verb and does not distinguish itself from siblings such as sw_measure or sw_assembly_mass.

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?

There is no guidance on when to call this versus sw_measure (measurement) or sw_assembly_mass (assembly-level mass). The agent must infer the choice from the name alone.

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