rhino-mcp

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rhino_subd_plane

Creates a SubD plane primitive in Rhino at a specified start corner. Set X, Y, Z, length, width, and face counts along U and V to generate the plane geometry.

Instructions

    Create a SubD plane primitive.
    
    Args:
    controller: RhinoController instance.
    x: X coordinate of start corner.
    y: Y coordinate of start corner.
    z: Z coordinate of start corner.
    length: Plane length along U.
    width: Plane width along V.
    count_u: Number of faces along U.
    count_v: Number of faces along V.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`x`	No
`y`	No
`z`	No
`width`	No
`length`	No
`count_u`	No
`count_v`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 9, 2026

TDQS

B3.1/5.0

Behavior2/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only says the tool creates a SubD plane. It does not mention orientation, coordinate-system behavior, insertion into the active document, or what happens to the object after creation. This is minimal behavioral transparency for a creation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded with a one-sentence purpose, followed by a clean Args list. Each line adds parameter meaning without unnecessary prose, making it easy for an agent to scan.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple primitive-creation tool, the description and input schema together are mostly sufficient to make a call. However, it omits placement/orientation context, such as how the U/V directions relate to the world axes, and it does not help the agent choose between this and related plane/primitive tools. The output schema covers return values, so that gap is acceptable.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate, and it does: x/y/z are defined as start-corner coordinates, length/width are defined along U/V, and count_u/count_v are defined as face counts. The meaning of every schema parameter is explained, though some details like units and coordinate orientation are left implicit.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Create') and resource ('SubD plane primitive'), making the tool's core purpose clear. It does not explicitly contrast with sibling tools like rhino_plane_surface or rhino_subd_box, but the 'SubD plane' identifier is specific enough to avoid major ambiguity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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 NURBS plane creation, other SubD primitives, or related primitives. There is no mention of alternatives, exclusions, or context such as 'use this when a SubD topology is needed.' The only implied usage comes from the tool name itself.

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

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