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

Annotations already cover the read-only, idempotent, non-destructive profile, so the description earns credit for adding substance beyond them: it discloses that Article 57 carries no indication text and no per-product URL, and that the authoritative EMA source document URL is returned instead. That is a real expectation-setting detail an agent would otherwise get wrong.

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 resource and scope, with no filler. The second sentence is justified because it preempts a likely expectation about indication text and URLs, though it is slightly defensive in framing.

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 carries the return-value burden, and it does so reasonably: it names the country list, the per-country MAH and pharmacovigilance location, and the source URL. It stops short of stating result shape or behavior when the name matches multiple products, which is the main remaining gap.

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 both parameters are already documented — including the near-exact-match behavior of name and the country restriction. The description only restates 'by name' and adds nothing about the country filter or how matching is resolved. 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?

States a specific verb and resource: retrieves the full Article 57 record(s) for one product by name, and enumerates the returned fields (countries, marketing-authorisation holder, pharmacovigilance location). This contrasts implicitly with the sibling ema_article57_search, but the description never names that alternative outright.

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 phrase 'for one product by name' implies this is the lookup path once a product is known, but there is no explicit when-to-use statement or pointer to ema_article57_search for discovery. The country parameter's role as a narrowing filter is left to the schema.

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