Fusion360 MCP Server

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

Annotations indicate this is a mutable (readOnlyHint=false), non-idempotent, non-destructive operation. The description adds that it patterns 'a body', implying it operates on existing geometry rather than creating new bodies from scratch. However, it lacks details on what 'pattern' entails (e.g., creates copies, maintains associations) or behavioral traits like error conditions or performance implications.

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?

Extremely concise with a single, front-loaded sentence: 'Pattern a body in rows and columns'. Every word contributes directly to the tool's purpose without any fluff or redundancy.

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 5-parameter mutation tool with no output schema and moderate schema coverage (40%), the description is minimal. It covers the core action but lacks details on inputs, outputs, error handling, or dependencies. Annotations help by clarifying mutability and safety, but more context would aid agent decision-making.

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 40% (only x_spacing and y_spacing have descriptions). The description mentions 'rows and columns', which aligns with y_count/rows and x_count/columns parameters, adding semantic context. However, it doesn't explain 'body_name' (the target) or default behaviors, leaving gaps despite partial compensation.

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 ('pattern') and resource ('a body'), specifying it's done 'in rows and columns'. It distinguishes from sibling 'circular_pattern' by implying rectangular vs. circular arrangement, but doesn't explicitly differentiate from other patterning or creation tools like 'mirror' or 'create_component'.

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 guidance on when to use this tool versus alternatives like 'circular_pattern', 'mirror', or array creation methods. It doesn't mention prerequisites (e.g., needing an existing body) or exclusions, leaving the agent to infer usage from context alone.

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