Create a closed sketch contour for connecting rods, levers, or tow bars by joining two circles with exact external tangent lines and shared endpoints.
Closed outer contour of two circles joined by their external tangent lines (connecting rod, lever, tow bar, arm). Tangent points are computed exactly and all ends are shared points.
| Name | Required | Description | Default |
|---|---|---|---|
| c1 | Yes | ||
| c2 | Yes | ||
| r1 | Yes | ||
| r2 | Yes |
Changes observed during successful MCP inspections.
v0.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare this is a non-destructive, non-idempotent write, so the safety profile is covered. The description adds genuine behavioral context beyond that — exact tangent-point computation and shared endpoints producing a closed contour — but omits whether an active sketch is required or what happens to existing sketch geometry.
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 tight sentences, front-loaded with the core geometric definition before the examples. No filler, though it does not bother to state the creating verb explicitly.
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 sketch-geometry creation tool with four undocumented parameters, no output schema, and no stated prerequisites, the definition leaves substantial gaps. An agent cannot know the expected input format or which document/sketch state is required to invoke it correctly.
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% and the parameter names (c1, c2, r1, r2) are cryptic. The phrase 'two circles' lets an agent guess c=center and r=radius, but no coordinate order, units, or sketch-plane frame is given, so the description does not compensate for the coverage gap.
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 names a concrete geometric result — a closed outer contour of two circles joined by external tangent lines — and parenthetically grounds it in real use cases (connecting rod, lever, tow bar). That is specific enough to distinguish it from siblings like catia_sketch_circle or catia_sketch_profile, though the verb (create) is only implied rather than stated.
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 indication of when to use this versus the many other sketch primitives, and no prerequisites are stated (e.g., whether an active sketch or open document is required). The agent must infer usage entirely from context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.