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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description earns credit by adding that no order is created and that the actual payment happens on the returned URL, which is real behavioral context an agent needs before deciding to call it.

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 purpose is front-loaded in one sentence, then args, then the payment caveat. Every line carries information; the only softness is the somewhat repetitive two-sentence payment note, which could be one sentence.

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?

With an output schema present, the description needn't explain return values, and it correctly focuses on parameters and the no-order behavior. It is nearly complete; missing only explicit handle-vs-product_id precedence and any hint about failure when a product is not found in the given language.

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%, so the description must carry the load, and it largely does: handle is defined via its source (search_org_products, same language), lang is given the full list of accepted codes absent from the schema, and product_id is framed as the fallback when handle is unknown. Only the precedence/interaction between handle and product_id is left implicit.

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?

First sentence names the specific resource (a single siilostomy.org product) and enumerates the returned content: photos, sizes, EUR amount, and the payment URL. This clearly separates it from search_org_products, but it never distinguishes itself from the sibling get_product, so the agent cannot tell which single-product tool applies.

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 one strong usage signal – the handle comes from search_org_products in the same language – and an exclusion ('does not create an order', payment happens on the returned url). However, there is no guidance on when to prefer this over the sibling get_product or what to do when neither handle nor product_id is known.

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