Fusion360 MCP Server

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

Annotations already declare this is a write operation (readOnlyHint=false), non-idempotent, and non-destructive. The description adds useful context about the two thread types (cosmetic vs modeled) which isn't captured in annotations, but doesn't provide additional behavioral details like permission requirements, side effects, or what happens if applied to non-cylindrical faces.

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 a single, efficient sentence that communicates the essential purpose without unnecessary words. It's front-loaded with the core action and immediately qualifies the thread types, making it easy for an agent to parse quickly.

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 9-parameter CAD modeling tool with no output schema, the description is minimally adequate. It covers the basic purpose but lacks information about return values, error conditions, or practical usage context. The high schema coverage helps, but more guidance would be beneficial given the tool's complexity.

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?

With 89% schema description coverage, most parameters are well-documented in the schema itself. The description adds minimal semantic context beyond what's in the schema - it mentions 'cylindrical face' which relates to face_index, and 'cosmetic or modeled' which relates to is_modeled, but doesn't provide additional interpretation or usage examples for the 9 parameters.

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 specific action ('Add threads') and target resource ('to a cylindrical face'), with explicit qualification of thread types ('cosmetic or modeled'). It distinguishes from sibling tools like 'create_hole' or 'chamfer' by focusing specifically on thread creation functionality.

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 no guidance on when to use this tool versus alternatives, nor does it mention prerequisites or constraints. While it specifies the target must be a cylindrical face, it doesn't explain how this differs from other face modification tools or when threads are appropriate versus other features.

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