create_ellipse

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

Annotations declare readOnlyHint=false and destructiveHint=false, and the description confirms a write operation ('Create') that is not destructive. It adds value by specifying the return structure: '{ ok, nodeId, name, type }', which is not in the annotations. This provides useful behavioral expectations beyond the schema.

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 extremely concise: two sentences that cover the core functionality, optional features, follow-up action, and return format. Every word adds value, and the most important information is front-loaded in the first sentence.

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 the tool's simplicity (6 optional parameters, no output schema), the description provides enough context: the creation action, parameter options, default parent, and a hint for converting to arc/pie/ring. It doesn't detail coordinate systems or units, but the schema already describes units as px. The return structure is mentioned, which is helpful since there's no output schema.

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 input schema has 100% description coverage for all parameters. The description adds extra semantics by clarifying the relationship between width and height ('a circle when width equals height') and stating that the default parent is the current page. This goes beyond the schema's simple descriptions like 'Width in px'.

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 'Create an ellipse', with an immediate explanation that setting equal width and height creates a circle. This distinguishes it from other shape creation tools like create_rectangle, create_frame, etc. The mention of optional sizing, naming, and positioning under a parent further clarifies its purpose.

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 tells when to use this tool (creating ellipses/circles) and provides explicit guidance on what to do afterward for modifications: 'To turn it into a pie, arc, or ring afterwards use set_arc.' This gives context for subsequent steps. However, it doesn't explicitly state when not to use it, but the uniqueness of the tool makes that less critical.

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