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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds genuine value beyond that by disclosing the shape of the result (the four legal-figure types plus the REP27 service), which the agent would otherwise have to guess. It stops short of noting match confidence or what happens on no-match.

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?

A single sentence that front-loads the verb and resource, then carries the payload in one clause. The parenthetical category list is compact and earns its place by helping an agent judge category coverage.

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 two-parameter read-only lookup with full schema coverage, complete annotations and an output schema, nothing an agent needs to invoke it correctly is missing. The description supplies the domain framing (REP27, EU legal figures) that the structured fields cannot.

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 100%, including format hints for 'lang' (ISO 639-1 examples) and free-text multilingual input for 'product'. The description adds nothing beyond the schema on either parameter, so the baseline 3 applies.

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 ('Searches') and a precisely scoped resource (the REP27 product-category catalogue), enumerated with example categories. It also declares the return payload (EU legal figure + REP27 service), which cleanly separates it from siblings like check_obligations or get_plans.

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 implied by the title question and the 'product' parameter, so an agent can infer this is the entry point for 'which legal figure do I need?'. However, no explicit alternatives are named — nothing says when to prefer check_obligations or about_rep27 instead, and no preconditions are stated.

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