draw_ellipse

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

With no annotations, description carries full burden. It explains that filled=False gives 1px outline and antialias only works for filled RGB sprites. But it does not disclose side effects (like overwriting pixels), error conditions, or behavior across frames/layers.

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?

Three sentences, no wasted words. The first sentence gives the core action, followed by brief parameter clarifications. Front-loaded and efficient.

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 10 parameters, no output schema, and no annotations, the description covers the essential behavior and key params but lacks details on color, frame, layer, and return value. Adequate for a simple drawing tool but not fully comprehensive.

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 0%, so description must compensate. It explains center_x, center_y, radius_x, radius_y, filled, antialias. But it omits explanations for color (format?), frame (existence?), layer, and filename. Assumes filename is obvious, but extra clarity would help.

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 states 'Draw an ellipse centred at (center_x, center_y) with the given radii.' It uses a specific verb (draw) and resource (ellipse), and the mention of radii distinguishes it from other shape tools like draw_rectangle.

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?

Provides context for circles (same radii) and explains parameters like filled and antialias. However, it does not explicitly state when to use this tool over alternatives (e.g., draw_rectangle) or mention prerequisites like frame or layer existence.

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