Creates an arc fillet between two lines using their intersection midpoint and a specified radius.
Create a simple arc fillet between two lines using their intersection midpoint.
| Name | Required | Description | Default |
|---|---|---|---|
| unit | No | ||
| radius | Yes | ||
| line_id_a | Yes | ||
| line_id_b | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, but it omits key questions: whether the two lines are trimmed to the new arc, what happens when the radius does not fit at the intersection, and what the tool returns. The midpoint-placement note is the only behavioral detail offered.
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?
A single front-loaded sentence with no filler; the core operation is stated immediately. It is efficient, though extremely terse for a 4-parameter geometry operation.
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 4-parameter mutation with no annotations, no output schema, and 0% schema coverage, the description is too thin. It should at minimum clarify units, ID format, and the effect on the source lines.
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% across 4 parameters, so the description must compensate. It loosely maps to radius and the two lines but says nothing about the unit parameter or the expected format of the line IDs, leaving a required enum and two ID fields undocumented.
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 gives a specific verb+resource ("Create a simple arc fillet between two lines") and adds the placement mechanism ("using their intersection midpoint"). An agent can distinguish this from fillet_3d and chamfer_2d, though the description never names those alternatives.
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?
No when-to-use guidance and no routing to alternatives such as chamfer_2d or fillet_3d, despite these being adjacent siblings. The reader is left to infer that this is the 2D/line-based variant.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.