skin_build

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

Annotations already declare readOnlyHint=false and destructiveHint=false; the description earns extra credit by disclosing that existing files are never overwritten, a new folder is created, and that it returns paths, validation, and the actual preview image. This is meaningful behavioral context beyond the annotations.

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?

Front-loaded with the outputs and the key constraint (new folder, no overwrite). A few dense sentences, mostly earning their place. Slightly terse on some nested semantics but no filler.

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?

No output schema exists, but the description explains return values (paths, validation, preview image) and the no-overwrite behavior. Combined with the nested Paint/Design schema, an agent has enough to call it correctly, though model/layer/palette details rely on the schema.

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 reported at 0%, but the $defs carry inline descriptions (rect as [x,y,w,h] face-local texels, color as existing palette key). The description adds meaning ('All six base parts require opaque palette colors', 'Paint is ordered rectangles within a face'), which compensates partially, but name, model, layer, and palette format remain undocumented in the description.

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 (build) and enumerates concrete outputs: 64x64 PNG, editable design.json, and front/back/side previews in a new named folder. This clearly distinguishes it from siblings like skin_validate, skin_preview, and skin_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?

Gives a useful usage constraint ('Use a new name for each revision; existing files are never overwritten'), which implies versioning workflow. However, it never explicitly contrasts with siblings (e.g., use skin_validate before building, or skin_preview to inspect), leaving the when-to-choose-this decision implied.

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