f360_create_sketch

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

With no annotations, the description does real work: it discloses that this is a state-creating operation tied to the active design, that it is a hard prerequisite for drawing, and how each plane maps to a view orientation. It does not cover failure/edge behavior (e.g. no active design, what happens if a sketch is already open, or whether the sketch must later be closed), which keeps it below a 5.

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?

Three compact sentences, front-loaded with the action and the mandatory ordering constraint, then the plane semantics. No filler or restated field names.

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 single-parameter, no-output-schema tool this covers purpose, prerequisites, and plane choice well. Minor gaps remain around preconditions (an active design must exist) and post-conditions (what the call yields, e.g. a sketch reference needed by later operations).

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 coverage is 100%, but the schema's enum description is only "Construction plane for the sketch". The description adds genuine meaning the schema lacks: XY = top view (most common for flat parts), XZ = front view, YZ = right-side view, giving the agent a basis for choosing a plane rather than guessing.

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?

States a specific verb and resource ("Opens a new sketch on a construction plane in the active Fusion 360 design") and explicitly positions itself as a prerequisite to the drawing tools. An agent can distinguish it from siblings like f360_extrude or f360_draw_rectangle without opening any schema.

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?

"MUST be called before any 2D drawing operation (draw_rectangle, draw_circle)" gives an explicit ordering rule and names the dependent siblings. It also routes plane selection with concrete guidance ("XY = top view (most common for flat parts)"), so there is nothing left to infer about when and how to use it.

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