Draw Spline

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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the mutation profile is known. The description adds the useful scoping fact that geometry lands in the most recent sketch, but it does not disclose the consequence of non-idempotency (repeated calls stack duplicate splines) or what happens when no sketch exists.

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 short sentences, front-loaded with what the tool does and followed immediately by the decision rule for spline_type. There is no redundant restatement of the title or padded phrasing.

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 three-parameter drawing primitive with annotations covering the safety profile and a schema covering most parameters, the description is adequate. It still leaves the sketch-precondition and error behavior implicit, which matters for an agent operating on a CAD document model.

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 documents degree and points thoroughly (67% coverage), and spline_type carries no schema description, so the description's explanation of 'curve through points' versus 'control-polygon spline' fills the one real semantic gap. It adds nothing about points or degree, but those are already well covered in the schema.

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 and resource ('Draw a spline') plus its target scope ('in the most recent sketch'), and disambiguates the two spline modes (fit_points vs control_points). It is easy to separate from drawing siblings like draw_arc or draw_line, though it never explicitly contrasts with them.

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?

Gives clear context for use: it draws in the most recent sketch, and it tells the agent which spline_type to pick depending on whether the points should be interpolated or used as a control polygon. It lacks explicit when-not guidance and does not state the prerequisite that a sketch must already exist and be active.

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