Create Ellipse

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the mutation/safety profile is covered. The description adds operational context about execution mode (background mode, no Computer Use), which is genuine added value, but says nothing about which document/artboard receives the object, layer defaults, or whether it fails without an open document.

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, front-loaded with the action ('Create an ellipse') before the execution-mode note. Nothing is padded, though the second sentence reads as server-wide boilerplate that could be trimmed or replaced with tool-specific behavior.

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 9-parameter creation tool with nested color objects and no output schema, the description is minimally viable: the rich schema lets the agent construct the call, but the description omits how the created ellipse is identified/returned for follow-up operations and whether a target document must already be open.

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%, including a well-documented coordinate_system enum with auto-detection rules, so the schema does the heavy lifting and the baseline is 3. The description adds no parameter-level meaning (no note on fill/stroke defaults, layer_name behavior, or units) beyond what the schema already says.

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?

States a specific verb+resource ('Create an ellipse'), matching the name precisely and clearly placing it among the sibling create_* tools (create_rectangle, create_line, create_path). It does not, however, explicitly differentiate itself from those siblings or state what shape/scope is produced.

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?

There is no guidance on when to use this versus create_rectangle, create_path, or create_line, nor any prerequisites (e.g., an open document, active artboard) or conditions under which it should not be used. The agent is left to infer usage entirely.

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