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

Annotations already establish the read-only, idempotent, closed-world, non-destructive profile, so the bar is lower. The description still adds real context: no account required, and that unauthenticated calls return only active records while authenticated calls also surface archived ones flagged `archivada: true`. That is useful behavioral disclosure, though it omits any error/not-found handling.

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 code types, then the account-dependent behavior. Efficient overall, though the parenthetical and dual 'sin cuenta/con cuenta' clause make the second sentence slightly 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?

An output schema exists, so return-value description is unnecessary, and the single parameter is fully specified. The description covers access model and code types adequately; the only real omission is routing guidance relative to buscar_subastas.

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?

With a single parameter at 100% schema coverage, the schema already documents `codigos` fully, including the 1..5 bound. The description's 'hasta 5' merely restates maxItems without adding format or validation detail beyond the schema, so baseline 3 is correct.

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+resource ('localiza subastas del BOE a partir de códigos') and enumerates the accepted code types. It is clear what the tool does, but it does not distinguish itself from the obvious sibling buscar_subastas, which also searches auctions.

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?

Usage is only implied: the agent infers it should be used when it holds a catastral reference, CRU, IDUFIR or BOE id. It never states when to prefer this over buscar_subastas, nor any exclusions, so the when-to-use guidance is left to inference.

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