sheet_metal_capabilities

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

With no annotations present, the description carries the full burden and does so: 'changes nothing' declares the read-only, side-effect-free nature. It also discloses that several operations rely on a preview API that 'may be missing', and that sketch_bend is hardcoded false because Fusion has no API for it — exactly the behavioral caveats an agent cannot otherwise infer.

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 read-only declaration and the 'call before a workflow' instruction are front-loaded, and the fallback guidance follows logically. The enumerated return key list is long and slightly awkwardly formatted, but since no output schema exists it earns its place.

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 zero-parameter, no-output-schema tool, the description supplies the full return shape (including the always-false sketch_bend and the preview_apis list), the availability caveat, and a workaround. Nothing an agent needs to call it and interpret the result is missing.

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?

The tool takes zero parameters, so the baseline is 4 and there is nothing to disambiguate. The description instead spends its space on the return shape, which is appropriate for a zero-arg query.

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 ('Report which sheet metal operations this Fusion API supports') plus the key qualifier 'changes nothing'. An agent can immediately distinguish this capability probe from the sibling action tools like sheet_metal_edge_flange or sheet_metal_unfold.

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?

'Call it before a sheet metal workflow' gives clear, actionable timing, and the description names concrete alternatives for the sketch_bend gap (sheet_metal_edge_flange or sheet_metal_contour_flange). It stops short of stating when-not to call it (e.g. once per session), so it falls just short of the top mark.

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