Create ellipse

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds only the editor-support caveat ('unverified: FigJam, Slides'), which is genuinely useful context, but says nothing about where the node is placed by default, how x/y behave, or what happens when parentId is omitted. For a mutation tool, that leaves meaningful behavioral gaps.

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 short and front-loaded with the ellipse/fill fact, so there is no wasted prose. However, its brevity stems from under-specification rather than disciplined editing — it is too small for a 10-parameter creation tool, so the concision is not fully earned.

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, 30% schema coverage, nested objects, a mutation hint in the annotations, and no output schema, the description should do far more work than two fragments. It omits the required-parameter contract, positional defaults, parent placement, and any relationship to sibling shape creators, leaving the agent to reconstruct the call from the schema alone.

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 description coverage is only 30% across 10 parameters, so the description carries a real burden — yet it mentions only 'optional fill'. It never notes that width and height are required, nor explains x/y coordinates, parentId, name, or how sizing interacts with the created node. The nested sizing object and idempotencyKey are documented in the schema, but the remaining parameters are left to the agent's inference.

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 is a bare noun phrase, 'An ellipse with an optional fill,' which essentially restates the tool name figma_create_ellipse and title 'Create ellipse'. It never supplies a verb or says the tool creates a node in a Figma file, and it does nothing to distinguish itself from the many sibling create_* tools (create_rectangle, create_polygon, create_star). The editor availability note is the only non-redundant content.

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 'Editors: Design; unverified: FigJam, Slides' clause gives a weak environment hint about where the tool is supported, but there is no guidance on when to use this tool versus figma_create_polygon, figma_create_star, or the composite figma_create_shapes_with_text. No prerequisites (e.g., a target page or parent frame) are stated.

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