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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, yet the description adds real value: anonymous calls return only 'fichas vigentes' from the public catalog, while authenticated calls also surface archived records flagged archivada: true. That result-set difference based on auth is not derivable from the structured fields.

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 dense sentences, front-loaded with the action and then the access caveat. Slight redundancy in 'Pública, sin cuenta; sin cuenta solo devuelve...', but nothing extraneous overall.

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?

An output schema exists, so return structure need not be described, and annotations cover the safety profile. The description fills the remaining gap (auth-dependent result scope) for a single-parameter lookup tool; only edge-case behavior such as invalid or partial codes is left unstated.

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% and the single parameter is fully documented, so the baseline is 3. The description lists the accepted code types and the 'hasta 5' cap, but both merely restate schema details (maxItems: 5, items described as the same identifier types) without adding format or validation nuance.

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 ('Localiza') and resource ('subastas del BOE') and enumerates the exact identifier types accepted (referencia catastral, CRU, IDUFIR, BOE). The 'a partir de códigos' framing distinguishes it from text-oriented siblings like buscar_subastas, though no alternative is named explicitly.

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?

Conveys useful context about access level ('Pública, sin cuenta') and how results differ by account state, which helps an agent decide whether the caller's context supports this tool. However, it never states when to prefer this over buscar_subastas or other search siblings, so the routing guidance is only implied.

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