fusion_sketch_spline

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

The description adds a useful behavioral detail by explaining that type can be 'fit_points' or 'control_points' and that control points 'uses degree'. It also specifies that coordinates are in mm. However, it does not disclose side effects on the sketch, whether a new sketch must exist first, or how plane selection affects the result. Annotations indicate readOnlyHint=falsetsy, so mutation is expectedholde, and the description is consistent with that.

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 extremely concise and front-loaded. It states the operation, input format, units, and type semantics in one compact sentence without filler or repetition.

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?

The description is adequate for a simple invocation, but it leaves important context implicit: whether the spline is added to the active sketch, how plane and sketch parameters interact, and what the returned value represents. Given that there is no output schema and the parameter schema has no descriptions, these gaps could cause an agent to call the tool without ensuring a sketch exists.

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?

With 0% schema description coverage, the description carries the full burden for parameter meaning. It usefully defines the required points format as [[x,y],...] in mm” and clarifies that type accepts fit_points or control_points, with degree related to control points. It does not explain the plane or sketch parameters, but those have defaults and are less likely to mislead.

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 identifies the operation: 'Draw a spline through points [[x,y],...] (mm).' It names the specific resource (spline), the required input format, and the type options. This distinguishes it immediately from sibling sketch tools like fusion_sketch_line or fusion_sketch_arc.

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 alternative sketch tools, nor when to choose fit_points versus control_points. It implies usage through the action verb 'Draw', but it never states prerequisites like needing an active sketch or when control points are preferable.

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