measure

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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds two behaviors the annotations cannot express: the call 'replaces the current selection' (a UI side effect) and coordinates are in mm/model space, which matters for agent-side coordinate construction. It does not cover error behavior for points that miss geometry, but with annotations carrying the safety profile this is solid.

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?

Two tightly packed sentences, front-loaded with the primary capability, followed by the side-effect warning. No filler or restatement of the tool name.

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?

An output schema exists, so return values needn't be explained, and the coordinate convention is covered. Gaps remain for a 4-parameter tool: the type1/type2 discriminators and the requirement that point2 be provided to get distance/angle are left to inference rather than stated.

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 0%, so the description carries the burden and does explain point1/point2 as [x, y, z] in mm model coordinates lying on the target geometry. However, type1/type2 (enum face/edge/vertex, defaulting to face) are never mentioned, so a quarter of the parameters — and the ones that determine what 'point lying on' means — are undocumented in both schema and description.

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 (measures) plus the two modes it supports: a single entity (area, length, diameter) or distance/angle between two points selected on geometry. An agent can tell what it does without opening the schema. No sibling is named, but no other tool in the list measures geometry, so the risk of confusion is low.

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 two modes are described, which implies when each applies (one point = single entity, two points = distance/angle), but there is no explicit when-to-use/when-not guidance and no comparison to related siblings such as get_bounding_box, get_dimensions, or get_mass_properties that could also answer measurement-ish questions.

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