rhino_get_length

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

Annotations already indicate readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering the safety profile. The description adds no behavioral context beyond what annotations already state—it does not mention units, error conditions, or that the curve is not modified. It is not contradictory, but it adds no extra value.

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, tightly written sentence with no filler. It is front-loaded with the core purpose and wastes no words. Perfect for a simple read-only measurement tool.

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?

Given the presence of an output schema and annotations that mark the operation as read-only, the description covers the essential information: the input type (curve) and the goal (length). It could mention units or edge cases (e.g., compound curves), but for a simple one-parameter tool, this is adequate. The only minor gap is not explicitly stating that the GUID must refer to a curve object, but that is already in the description.

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 schema only describes the 'guid' as 'Object GUID', which is generic. The description specifies that the object must be a curve, adding meaningful semantic constraints beyond the schema. This is a useful clarification, though minimal given there is only one parameter.

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 'Calculate the length of a curve' clearly states the action (calculate), the resource (curve), and the result (length). It is specific and distinct from sibling tools like rhino_get_area or rhino_get_volume, which target different geometric properties. The verb and object are 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 provides no guidance on when to use this tool versus alternatives such as rhino_distance (for distance between points) or rhino_get_area (for surfaces). There is no mention of prerequisites (e.g., the curve must be a closed loop or a single curve). It leaves the selection entirely to inference.

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