Measure the length of selected curves in Rhino. Get accurate curve length values directly from the model for design and analysis.
Measure the length of selected curves.
Args:
controller: RhinoController instance.
Returns:
Dict with command result containing curve length.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the burden of behavioral disclosure. It states the tool measures length and returns a dict, but it does not explicitly confirm the operation is read-only/non-destructive, nor does it describe behavior for empty selections, multiple curves, or units.
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 appropriately sized and front-loaded with the core operation. The Args and Returns sections are brief, though the return line is somewhat vague ('command result containing curve length'); overall there is no wasted prose.
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 an output schema, the description covers the basic operation adequately. However, it omits practical details such as selection prerequisites, behavior with multiple curves, units, and error conditions, making it minimally viable rather than 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 input schema has zero parameters, so there is little for the description to document at the argument level. The 'controller: RhinoController instance' line is not in the schema but reads as contextual dependency rather than a user-supplied parameter, so no actual call parameters are left undocumented.
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 clearly states a specific verb and resource: 'Measure the length of selected curves.' It is unambiguous about what the tool does, though it does not explicitly differentiate itself from sibling rhino_curve_length, which may target a specific curve by identifier.
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 phrase 'selected curves' implies the tool relies on the current Rhino selection, which is useful context. However, there is no explicit guidance about when to choose this tool over rhino_curve_length or how to handle cases with no selection or multiple selected curves.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.