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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), so the description only needs to add context beyond that. It does: it discloses that summaries are Atlas-generated rather than source text, and that the full document text is not returned but lives behind the official link. Those are genuinely useful behavioral facts an agent cannot derive from the annotations.

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 well-formed sentence, front-loaded with the core purpose and then enumerating contents. Nothing is padded, though the long comma-list of returned fields makes it dense; it could be broken into two sentences for readability.

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?

With no output schema, the description carries the burden of describing the return payload, and it does so thoroughly by listing every field of the record. It also notes that the full text must be reached via the official link. Only the empty/no-match and disambiguation behavior is left implicit (partially covered by the schema's candidate note).

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%, so both parameters are fully documented in the schema, including the important 'sin año, devuelve los candidatos' fallback. The description echoes the reference and slug examples but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 concrete action and resource: it returns the complete record ('la ficha completa') for a document, reachable either by reference or by slug. The enumeration of the record's contents (epígrafe, problema jurídico, resumen, citas, descriptores, relacionados, enlace oficial) makes the output scope very concrete. It never contrasts itself with the sibling atlas_buscar, so the agent must infer the lookup-vs-search distinction.

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 tells the agent the two accepted lookup keys ('por referencia ... o por slug'), which implicitly frames this as a direct-identifier fetch rather than a search. However, it never explicitly says when to use this instead of atlas_buscar, nor any prerequisite such as requiring an exact reference or slug. Usage is implied rather than prescribed.

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