add_circle

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

There are no annotations, so the description carries the burden of explaining behavior. It does state the side effect ('Add a circle') and the return value ('Returns circle_index'), but it omits details like whether the sketch must pre-exist, coordinate format, or failure behavior. This is adequate but not rich.

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 three short sentences with a clear front-loaded verb, then mode-specific requirements, then return behavior. Every sentence contributes useful information with no filler or redundancy.

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 7-parameter tool with no annotations or output schema, the description covers the main mode dependencies and the return value, which is helpful. However, it leaves the required 'sketch' parameter and point array formats unexplained, making it minimally adequate rather than fully 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 0%, so the description must compensate. It does add meaningful semantics by linking kind to required parameter groups and clarifying the center_radius and 3pt variants. However, it does not explain the format of point/center arrays or the required 'sketch' parameter, leaving gaps.

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 tool's action ('Add a circle') and the two construction modes, but it does not explicitly distinguish this from sibling tools like add_ellipse or add_arc. It is specific and unambiguous enough for selection.

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 gives explicit usage context by defining the two kinds ('center_radius' vs '3pt') and which parameters each requires. It lacks explicit exclusions or alternatives like 'use add_ellipse for ellipses', but the mode guidance is clear and actionable.

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