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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered and the bar is lower. The description still adds real context beyond them: data provenance ("live Medusa catalog"), currency (PLN), and a domain constraint that the products are dietary supplements rather than medicine, which shapes how an agent should frame answers. It does not say what happens when a handle is unknown.

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?

Four short sentences, front-loaded with the primary return value and then the secondary educational content. Every sentence carries information; only the terse list of educational sections is slightly clipped.

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 single-parameter read tool with an output schema, the description is close to complete: it covers provenance, currency, and the domain caveat, and the output schema handles return structure. Minor gaps remain on lookup failure behavior and on explicit routing versus the search siblings.

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% and the single parameter already carries an example ("reishi"), so the baseline is 3. The description clarifies the lookup is handle-based (not SKU or name) and that SKU is an output rather than an input, but it adds no format or matching-rule detail beyond the 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 names a specific verb and resource (returns product variants by handle) and enumerates the payload (SKU, price in PLN, availability, plus educational sections). The lookup key ("by product handle") implicitly separates it from the search-style siblings, but no sibling is named, so an agent must infer that search_products/polec_produkty cover non-handle lookups.

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?

Usage is only implied: the tool takes a handle, so it is usable when a handle is already known, and the sibling set (search_products, szukaj_produktow, recommend_products) suggests discovery paths. There is no explicit when-to-use, when-not-to-use, or fallback statement for a missing/invalid handle.

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