Fusion360 MCP Server

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

Annotations indicate this is a non-readOnly, non-idempotent, non-destructive operation, which the description doesn't contradict. The description adds minimal behavioral context by mentioning the plane options and offset capability, but doesn't disclose important details like whether sketches are persistent, if they can be edited later, or what happens on failure. With annotations covering basic safety, this earns a baseline score.

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 extremely concise—a single sentence that's front-loaded with the core action. Every word earns its place without redundancy, making it easy to parse quickly. No unnecessary details or verbose explanations are included.

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?

Given the tool has no output schema and annotations cover basic safety, the description is minimally complete. It identifies the action and parameters but lacks depth on usage context, return values, or error handling. For a creation tool with 2 parameters, this is adequate but leaves gaps in practical guidance.

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 50% (only 'z_offset' has a description). The description mentions 'plane' and 'offset' but doesn't add meaningful semantics beyond what the schema provides—it doesn't explain what the planes represent, default behaviors, or offset implications. With partial schema coverage, the description doesn't adequately compensate, warranting a baseline score.

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 verb ('Create') and resource ('new sketch'), specifying it occurs on specific planes (xy/yz/xz). However, it doesn't differentiate from sibling tools like 'draw_rectangle' or 'draw_circle' that might also create sketches, leaving some ambiguity about when to use this versus other drawing tools.

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. It mentions 'optionally offset' but doesn't explain scenarios where offsetting is beneficial or when other tools like 'create_construction_plane' might be more appropriate. No explicit when/when-not instructions are given.

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