draw_arc

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

With no annotations, the description carries the full burden. It discloses that angles are in degrees and counterclockwise, which is helpful. However, it omits critical behavioral details such as the angle reference (e.g., positive x-axis), the direction from start to end, and what happens if start equals end. The description is too sparse for a drawing primitive where orientation and semantics matter.

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 highly concise and front-loaded with 'Arc', wasting no words. It is a single phrase that quickly conveys the essential concept. However, the extreme brevity likely contributes to the lack of behavioral clarity, so it is concise but not overly so.

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?

Given 6 parameters, 0% schema description coverage, and no annotations, this description is insufficient. It does not explain the angle reference, coordinate system, layer defaults, or return value. A tool like this needs more context to be used correctly, especially for users unfamiliar with CAD conventions.

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 description adds meaning to schema parameters by stating 'center, radius, start/end angles in degrees (CCW)', which clarifies that cx/cy are the center, radius is the radius, and angles are in degrees. However, it does not mention the 'layer' parameter at all, and it does not clarify the coordinate system or units for radius. Since schema coverage is 0%, the description partially compensates but not fully.

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 tool as creating an arc and specifies its defining parameters (center, radius, start/end angles). It distinguishes from siblings like draw_circle or draw_ellipse by mentioning angles. However, it lacks an explicit verb, relying on the tool name 'draw_arc' to convey the action.

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 is provided on when to use this tool versus alternatives such as draw_circle or draw_ellipse. There is no mention of specific use cases, prerequisites, or exclusions.

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