Add an ellipse

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

Annotations already signal mutation via destructiveHint=true, and the description does not contradict that. Yet the description adds no operational detail beyond 'creates': it does not explain where the ellipse is inserted, how parentId interacts with the current selection, or what side effects the creation has. For a create operation, this leaves important behavior undisclosed.

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 one tight sentence that front-loads the core action and then adds one valuable nuance. There is no filler or repetition beyond an acceptable restatement of the title.

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 mutating creation tool with 7 parameters, no output schema, and no explicit insertion semantics, the description is too thin. An agent needs to know where the ellipse lands, whether parentId is effectively required, and what the call returns or affects. None of that is covered.

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 only 43% schema description coverage, the description should compensate for undocumented parameters, but it only adds meaning to width/height via the equal-dimensions-circle note. It does nothing for x, y, name, or parentId, so an agent still lacks semantics for most parameters.

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 uses a specific verb and resource: 'Creates an ellipse.' It adds the distinctive geometric behavior that equal width and height produce a circle, which differentiates it from sibling create_* tools such as create_rectangle or create_text.

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 implies usage via the examples 'an avatar, a dot, a radio button,' suggesting when a circle/ellipse is desired. However, it does not explicitly say when to choose this over alternatives like create_rectangle, nor does it mention exclusions or fallback conditions.

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