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

The annotations already declare that this is a non-read-only, non-destructive, non-idempotent mutation. The description adds useful behavioral context by saying the marks are clipped to a shape and refused on a screen. It does not explain what the mutation actually creates, how repeated calls behave, or other operational constraints, but with annotations covering the safety profile a 3 is appropriate.

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 description is short and front-loads the action, but the second sentence is awkward and unclear ('On a screen the marks are refused as a picture drawn onto it'). It is concise without being structurally complete.

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 12-parameter mutation tool with no output schema and 0% schema description coverage, the description is too thin. It leaves most parameters unexplained and does not describe the result of the operation, so an agent would need to infer heavily from 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 description coverage is 0% across 12 parameters. The description only names four of the five kind values and implies shape_id via 'clipped to a shape'; it does not explain ink, seed, angle, color, width, jitter, opacity, spacing, coverage, name, or the crosshatch kind. This is far from compensating for the undocumented schema.

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 gives a specific verb and resource: add hatch/stipple/facet/strata marks clipped to a shape on a drawing board. This is more than a restatement of the title, but it does not explicitly distinguish the tool from siblings such as set_pattern or scatter.

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 provides implied usage context by naming the drawing board and noting that marks are refused on a screen, which is a when-not condition. However, it gives no explicit alternatives or guidance on when to choose this tool over related tools like set_pattern or scatter.

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