set_mask

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

With no annotations, the description carries the full behavioral burden, and it does disclose real traits: white = visible mask semantics, the document-px coordinate space, image path alignment, and hide_all initialization. It stops short of saying whether an existing mask is replaced, what permissions are required, or how density interacts with the result.

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 mask semantics are front-loaded before the mode enumeration, and nearly every clause carries a format, unit, or behavioral detail rather than filler. It reads as one dense run-on string, but no sentence is wasted.

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 9-parameter mutation tool with no annotations, no output schema, and 0% schema coverage, the description covers the primary modes well but leaves invert/density and the set-vs-update-vs-remove relationship unexplained. Adequate as a minimum viable definition, not complete.

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 0%, so the description must compensate and it partially does: it defines the kind modes, the box=[x,y,w,h] document-px format, the path requirements (grayscale/alpha, aligned to content), the feather unit (px), and hide_all semantics. Four of nine parameters — layer, project, invert, and density — get no explanation, and density in particular is non-obvious.

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 centers on "Layer mask (white = visible)" and enumerates the mask kinds (rect/ellipse/image/paint), so an agent can infer this configures a layer mask. However, the action verb is never stated and there is no differentiation from the tightly related siblings update_mask, remove_mask and mask_stroke, leaving the exact purpose only implied.

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?

It gives mode-level guidance — paint is paired with mask_stroke, hide_all=true starts fully hidden — which is useful conditional context. But it never states when to choose set_mask over update_mask or remove_mask, so the core when-to-use decision is left to inference.

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