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

Annotations declare readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds meaningful behavioral context beyond that: it returns watermarked previews, a slide list, and a studio link, and it takes ~40-60 seconds. However, it does not clarify whether this overwrites anything, what 'watermarked' implies for downstream use, or what preconditions exist (e.g., uploaded screenshots required first).

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?

Three compact sentences: purpose, output, timing. Front-loaded with the core action and no filler. Slightly telegraphic—'Claude art-directs'—but efficient throughout.

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, so the description usefully sketches the return (watermarked previews, slide list, studio link) and the runtime. But it omits prerequisites (uploaded screenshots / app must exist) and whether the result is a persisted set the other sibling tools (edit_set, export_set, get_set) operate on. Adequate but with notable gaps for a generative, open-world tool.

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 80%, so the schema already documents most parameters including enums for device, opener, and include, and focus. The description adds no per-parameter syntax or format detail beyond what is in the schema, so baseline 3 is appropriate.

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 states a concrete verb and resource: Claude art-directs a full App Store screenshot set (opening shot, headline per slide, close-ups, palette) from uploaded screenshots. This is specific about what gets produced. It does not explicitly differentiate from siblings like edit_set or export_set, but the generative nature is clear enough that confusion is unlikely.

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?

Phrasing implies usage (create a new set needing uploads), but there is no explicit when-to-use guidance or condition contrasting this with edit_set, get_set, or export_set. An agent must infer that design_set is the initial creation step and edit_set modifies an existing set.

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