Fillet Two Entities

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

Annotations indicate readOnlyHint=false and destructiveHint=false, so the agent knows it modifies without destroying. The description adds detail: returns a new arc or source line for radius=0, and the LINE+LINE limitation goes beyond annotations.

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 sentences no wasted words. First sentence defines purpose and output, second sentence specifies limitation and special case. Ideal front-loading.

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 modification tool with 4 parameters and an output schema, the description covers the core operation, return value, and the LINE+LINE constraint. The trim parameter is described in the schema but not in the description; still adequate.

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 input schema covers all 4 parameters with descriptions (100% coverage). The description adds value by explaining radius=0 behavior, though it doesn't elaborate on other parameters beyond 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 it rounds a corner with a tangent arc, using a specific verb and resource. It distinguishes from the sibling chamfer tool by indicating a rounding operation, and specifies that it returns info on the new ARC entity.

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 a key usage constraint with 'V1 supports LINE+LINE only', telling the agent when this tool applies. However, it does not explicitly state when not to use it or mention alternatives like chamfer.

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