ai_add_ellipse

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

With no annotations, the description carries the disclosure burden and does state that the tool mutates the current document by drawing an ellipse, with x/y interpreted as top-left coordinates. It does not disclose default fill behavior when fr/fg/fb are omitted, layer placement, or behavior when no document is open, leaving moderate uncertainty.

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?

A single compact sentence front-loads the action and then maps the parameters clearly. There is no filler, and the essential information is easy to scan.

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?

The core invocation (x/y/w/h plus optional fill) is adequately covered by the schema and description, and there is no output schema requiring return-value explanation. However, missing default behavior for omitted fr/fg/fb and no mention of stroke or active-document errors make it minimally viable rather than complete.

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 100%, so the schema already documents every parameter with units and ranges. The description repeats the x/y top-left, w/h, and fr/fg/fb fill-color roles but adds no new constraints, defaults, or relationships beyond the schema, earning the baseline 3.

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 concrete verb ('draw') with a specific resource ('an ellipse in the current Illustrator document'), and the shape type clearly distinguishes it from sibling tools like ai_add_rectangle, ai_add_polygon, and ai_add_text. It also defines the core parameter mapping in the same sentence.

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 clearly implies when to use this tool: when an ellipse should be drawn in the active Illustrator document. However, it does not explicitly state when not to use it or name alternatives, so the routing guidance is only implied rather than explicit.

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