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

Annotations already indicate readOnly, idempotent, non-destructive, so the description doesn't need to rehash that. The description adds value by revealing the return includes a product-page URL and a direct checkout link, which is beyond a simple fetch and helpful for agents expecting only basic data.

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?

Two sentences, front-loaded with the core function and scope, followed by additional return details. Every word earns its place; no fluff or repetition.

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?

Given the tool is a simple single-parameter fetch, the description covers all essential aspects an agent needs to know: what it does, what it returns, and where the parameter comes from. The only minor gap is not explaining the format of the checkout link, but that's not critical for invocation.

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?

The schema already documents the 'sku' parameter with an example, achieving 100% coverage. The description adds context that the SKU comes from search_products, but that's minor; the schema is sufficient for parameter understanding.

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?

Clearly states it fetches price, stock, and details for a single product by SKU, and explicitly notes it is specific to 'Gameshop Enter', distinguishing it from generic alternatives. The verb 'Fetch' and resource 'one product' are specific and actionable.

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?

The description implies it should be used when you have a SKU from search_products, as it says 'by its SKU (as returned by search_products)'. This suggests a clear workflow: search first, then fetch details. However, it doesn't explicitly say 'do not use for listing' or contrast with sibling tools like get_quote, so it's not a full 5.

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