set_sculpt_mask

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

With no annotations, the description does real work: it discloses that no mode switch is required ('Works in any mode'), that non-listed vertices retain their mask rather than being reset, that invert ignores all other arguments, and that clear removes the mask entirely. What's missing is whether the operation is undoable / requires the object to be a mesh with a mask layer, and any error behavior — hence not 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?

Front-loaded with the one-sentence purpose and the value scale, then a compact Args/Returns block. Every line adds information; no filler or restated titles beyond what's needed as anchors.

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 6-parameter mutation tool with zero annotation coverage, the description plus the output schema together cover what the agent needs: argument interactions, scope, and a return summary. It stops short of prerequisites/permissions and failure modes, which is the only remaining gap.

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 carry the load and it does for every parameter: value's 0.0–1.0 polarity, vertex_indices' partial-update semantics, vertex_group's weight-multiplied formula and resulting unmasked complement, and the override/ignore interactions of invert and clear. This is meaningfully more than the schema's bare titles and defaults.

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 opening line gives a specific verb and resource ('Mask part of a mesh') plus the effect ('so sculpt brushes and filters leave it alone'), which immediately distinguishes it from the brush/brush-property siblings like set_sculpt_brush. An agent knows exactly what this mutates and why.

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?

Usage is implied through the mask semantics (1.0 protected, 0.0 free) and the note that omitting vertex_indices/vertex_group applies to the whole mesh, plus 'Works in any mode' which answers a real precondition question. However, it never names an alternative or states when not to use it, and it does not relate itself to enter_sculpt_mode/exit_sculpt_mode or the other sculpt siblings.

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