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, and non-destructive operation. The description adds that it offsets 'connected sketch curves', implying it works on 2D sketch geometry within a loop, which provides useful context beyond annotations. However, it lacks details on side effects (e.g., how it modifies the sketch), error conditions, or performance considerations, limiting its transparency.

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 front-loads the core action ('offset connected sketch curves') and adds a key detail ('direction is determined by the direction_point'). There is no wasted verbiage or redundancy, making it highly concise and well-structured for quick understanding.

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's moderate complexity (5 parameters, no output schema), the description is adequate but incomplete. It covers the basic purpose and direction mechanism, but lacks information on return values, error handling, or interaction with other sketch tools. With annotations providing safety cues, it meets minimum viability but could be more comprehensive for a geometric operation.

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 100%, so parameters are well-documented in the schema. The description adds minimal value by mentioning 'direction_point' (implied by direction_x and direction_y parameters) and that curves are 'connected', but doesn't clarify semantics like what 'curve_index' refers to in a loop or how 'sketch_name' defaults work. This meets the baseline for high schema coverage.

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 action ('offset') and target ('connected sketch curves'), with a specific mechanism ('direction is determined by the direction_point'). It distinguishes from siblings like 'offset_faces' (which operates on faces) and 'extend_curve' (which extends rather than offsets). However, it doesn't explicitly differentiate from all similar tools (e.g., 'draw_spline' for creating curves), keeping it from a perfect score.

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 doesn't mention prerequisites (e.g., needing an existing sketch), exclusions (e.g., not for 3D geometry), or direct comparisons to siblings like 'offset_faces' or 'draw_spline'. This leaves 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.