fillet

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

With no annotations provided, the description carries the full burden. It warns that the tool updates the JCAD document and requires prior state inspection. It also describes the fallback behavior and return value. These disclosures are significant, though it does not mention side effects like reversibility or permission requirements, preventing a 5.

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 front-loaded with a clear purpose statement and then systematically presents parameters and a warning. It is somewhat lengthy but every sentence serves a purpose. The structure is logical, though the param list could be tightened by grouping related transformations, making it not perfectly concise.

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 description provides a comprehensive overview: purpose, parameters, return value, mutation warning, and prerequisite. However, it does not explain how to determine the edge index for the fillet, which is critical for using the tool correctly. This gap in operational guidance prevents a 5, but overall the description is well-rounded.

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?

The description's param list adds substantial meaning beyond the schema's basic types and defaults. It explains that 'shape' can be a name or index, defines default color behavior, and clarifies edge, radius, and rotation semantics. This compensates well for the schema's lack of descriptions, even if jcad_path is only referenced in the warning rather than the param list.

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 function with a specific verb and resource: 'Apply a fillet operation on an object.' It also distinguishes this tool from siblings like chamfer and other edge operations, and clarifies behavior with the fallback to the last created object when no input is provided.

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 provides clear context: it explains the default operand behavior ('If no objects are provided as input, the last created object will be used as operand') and explicitly instructs the agent to use 'get_current_cad_design' before invoking the tool. However, it does not explicitly mention alternatives or when not to use the tool, so it falls short of a perfect score.

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