Extend Curve

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 description's job is supplementary. It usefully discloses the unit convention (cm not mm, angles in degrees) and which end is affected, but says nothing about the non-idempotent character of repeated calls or what happens when no intersection exists in the extension direction.

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 sentences with no filler, and the core action is front-loaded ahead of the units caveat. Every clause carries information an agent needs.

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?

No output schema exists and the tool has a mutation with a non-idempotent hint, yet the description omits failure behavior (no intersection found, point not near a curve end) and leaves sketch_name entirely undocumented. The units clarification helps, but the definition is not complete for a 4-parameter editing operation.

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?

Schema coverage is 75%, so the point_x/point_y/curve_index meanings are already documented in the schema. The description adds only the global unit convention; it does not explain the undocumented sketch_name parameter or how the point relates to curve selection beyond the schema's own wording.

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 ('Extend a sketch curve') plus the precise scope of the action ('to the nearest intersection'), which lets an agent distinguish it from trim_curve or offset_curve. It stops short of naming any sibling explicitly, so it is clear but not fully differentiated.

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?

No guidance on when to choose this over trim_curve or offset_curve, and no prerequisites or preconditions (e.g. sketch must be active or in edit mode are never mentioned). The only usage-like content is the mechanical note that the end nearest the given point is extended, which describes behavior rather than when-to-use.

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