Create Ellipse

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

The annotations already indicate a write operation via readOnlyHint=false, so repeating that is unnecessary. The description adds the geometric interpretation of the major axis vector, which is useful, but it does not disclose defaults, drawing-state requirements, or side effects beyond what the annotations already signal.

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?

Two short sentences with the core action front-loaded and no filler. Every word serves a purpose: identifying the entity type and clarifying the key geometric parameter.

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 schema covers all parameters and an output schema exists, so return-value documentation is unnecessary. The description provides the essential geometric concept for correct invocation. Minor gaps such as the meaning of a null ratio default or drawing-state prerequisites are not critical for this simple creation tool.

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 100%, so the baseline is 3. The description adds the 'vector from the center' framing for major_x/major_y, but the schema already describes them as 'relative to center.' It adds no extra meaning for ratio, color, or layer, though those are already documented in the schema.

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 the operation: 'Create an ellipse.' It also adds a meaningful geometric detail about major_x/major_y defining the major axis vector from the center, which distinguishes this from sibling entity creation tools like entity_create_circle or entity_create_line.

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 when an ellipse is needed, but it does not explicitly state when to use this tool versus alternatives, nor does it mention when not to use it. An agent must infer selection primarily from the tool name and resource type.

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