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

Annotations already cover readOnlyHint, idempotentHint and openWorldHint, so the safety profile is given. The description goes beyond them by enumerating the returned payload (all English titles, document and in-force dates, resource type, EuroVoc concepts, authoring bodies) and asserting publisher-authoritative provenance, which is genuine added context for trusting the result.

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?

Front-loaded with what the tool returns, followed by the authoritative-provenance note; sentences are dense and mostly earn their place. The parenthetical examples and the em-dash adjective stacking add a little length without new information, so a small deduction from top marks.

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 burden of describing return values, and it fully enumerates them. With both parameters optional and mutually exclusive, the description's guidance plus schema descriptions leave no ambiguity about how to invoke or what to expect.

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%, and the parameter descriptions already explain the CELEX and CELLAR UUID formats plus the 'give this OR that' exclusivity, so the baseline is 3. The description reinforces that either key accepts a lookup but adds no syntax or format 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?

States a specific verb and resource: retrieve full metadata for one EU document, keyed by CELEX number or CELLAR UUID. Concrete examples (32024R1689 for the AI Act) and the named data source (Publications Office CELLAR) pin down exactly what comes back, and it is clearly differentiable from the cellar_search_works / cellar_sparql siblings.

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?

Strongly signals context of use: single-document lookup by identifier, and 'AUTHORITATIVE for the identity and classification of an EU act' tells the agent to prefer this for identity/classification questions. It stops short of explicitly naming when to reach for cellar_search_works or cellar_sparql instead, so it lacks a hard when-not.

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