sw_assembly_mass

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds only what the tool yields (mass and CG); it says nothing about units, whether it requires an assembly versus a part document, or how it behaves if the document is empty or unloaded.

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 sentence, front-loaded with the resource and outputs, with no filler. The parenthetical is illustrative rather than redundant, though it is informal for a tool description.

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 simple read-only query with a fully documented optional parameter this is close to adequate, but with no output schema the description should say more about the return shape and units (mass and CG coordinates) so the agent knows what it will receive.

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 single optional 'doc' parameter is fully documented in the schema (100% coverage), so the baseline is 3. The description adds no meaning about accepted formats (title vs path) or the fallback-to-active-document behavior beyond what the schema already states.

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 resource (total mass and centre of mass of the assembly) with a concrete verb implied ('compute/report'), and the parenthetical anchors the purpose to a real engineering task. It does not, however, differentiate itself from the sibling sw_mass_properties, which an agent could easily confuse it with.

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?

Usage is only implied: the '(balance a drone on its CG)' note hints at a scenario, but there is no explicit when-to-use, no prerequisite (e.g. an assembly must be open), and no routing to or away from sw_mass_properties.

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