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

With no annotations, the description carries the full behavioral burden. It discloses the shape of the result (risk class, obligation set with article numbers, application date, fine ceiling) and implies deterministic rule application over recall, but says nothing about determinism, versioning of the regulation, permissions, or rate limits. Output content is covered; operational behavior is not.

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?

Three sentences, each earning its place: purpose and return values first, scope of coverage second, usage guidance third. No filler and the most decision-relevant content is front-loaded.

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 10-parameter tool with no output schema, the description compensates by enumerating return values and the regulatory scope covered. It lacks detail on ambiguous inputs (e.g. how role interacts with prohibited practice) and output structure, but an agent has enough to call it correctly and interpret the answer.

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 70%, so the schema already documents most parameters, and the description adds no parameter-level syntax or format detail beyond the enum lists in the schema. It does supply framing that maps to key inputs -- Article 6(3) exemption, Annex III, staggered application dates -- which slightly reinforces their meaning.

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 gives a specific verb and resource ('Classify an AI system under Regulation (EU) 2024/1689') and enumerates the exact outputs returned: risk class, obligation set with article numbers, application date, and maximum fine. It also scopes coverage to Articles 5, 6/Annex III, 53, and 50, which no sibling tool (cbam_cost, uae_corporate_tax) overlaps with.

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 states an explicit when-to-use rationale -- 'Use this rather than recalling the classification' -- and justifies it by naming the error-prone parts (Annex III list, Article 6(3) exemption, staggered dates). It stops short of naming a sibling alternative or stating exclusions, but the guidance is clear and actionable.

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