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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, and the description adds substantive behavior beyond them: only the file header is read, the photo is never stored or viewed, public price and the supplied download URL are fetched via GET, and the analysis covers only resolution and aspect ratio — not sharpness or lighting. It also discloses what is returned (recommended size, alternatives, crop share, live price per size).

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 front-loaded with purpose, then usage, inputs, scope limits, and safety, in a logical order with no wasted clauses. The final Dutch sentence only restates the opening in another language, which is mild redundancy given the title is already Dutch.

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 5-parameter, nested-object tool with no output schema, the description covers inputs, the return payload, privacy/scope limits, and the network side effects an agent must anticipate. Nothing needed to call it correctly or set user expectations is missing.

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 100%, so the baseline is 3; the description adds real meaning by explaining that width/height are pixels, that a user-supplied photo is read only at the header level, and that the URL is a GET-based alternative. It does not explain the wanted_size parameter's role beyond an implied 'which canvas size fits', so it falls short of full marks.

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 first sentence states a specific verb and resource: size and price advice for a custom paint-by-numbers kit made from the customer's own photo. It is immediately distinguishable from the siblings search_products and shop_info, which are generic shop tools rather than photo-based sizing advice.

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 explicit triggers — photo suitability, canvas size choice, and cost of a kit from one's own photo — plus explicit exclusions: it does not store or upload the photo and does not create an order or payment. Nothing about when to reach for this tool vs. others 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.