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

Annotations already declare the operation is read-only, idempotent, and non-destructive. The description adds valuable behavioral context beyond that: it is public and requires no account, and it explains that results differ depending on authentication—only current catalog entries without an account, but archived ones too when authenticated. This is substantive, nontrivial behavior the agent could not infer from annotations or schema.

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 sentences, each earning its place: the first explains what the tool does and its accepted inputs, and the second provides the auth-dependent behavioral nuance. No filler, no redundancy with annotations, and the key action 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?

The single parameter is fully documented in the schema, the annotations cover safety, the output schema exists so return values need not be explained, and the description adds the only missing behavioral context—public access and archived-record visibility. Nothing essential is left out for an agent to invoke this tool correctly.

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 the baseline is 3. The tool description repeats the code types and the 1-5 limit already present in the schema description, adding no new parameter-level detail such as format, matching semantics, or case sensitivity. It does not compensate 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?

The description states a specific verb and resource: 'Localiza subastas del BOE a partir de códigos.' It also enumerates the exact code types accepted (referencia catastral, CRU, IDUFIR, identificador BOE), which clearly distinguishes this tool from broader search siblings like buscar_subastas or search.

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?

The description gives clear usage context: this tool is for looking up auctions by structured codes rather than free-text queries, and it clarifies account-dependent behavior. It does not explicitly name alternative tools or state when not to use it, so it misses the top bar for explicit exclusions.

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