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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuinely useful context beyond that: no account is required, results are published once TuLotero posts the escrutinio, and the response arrives as Markdown tables ready to display. It stops short of describing what happens when escrutinio is not yet available.

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?

One dense paragraph that is front-loaded with the purpose and payoff ('combinación ganadora... escrutinio con premios por categoría'), followed by example queries and the supported games. It is appropriately sized for a 12-game tool, though the game enumeration duplicates the enum-like list already in the schema and the comma-chained clauses are heavy to parse.

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, and the description compensates by detailing the return content field-by-field (winning combination, jackpot status, reintegros, El Millón, category prizes, next draw) and its Markdown format. Combined with the auth-free note and the date default, an agent has everything needed to call and interpret it.

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 already fully documented, including the free-form 'cuando' formats and the no-date default. The description reiterates the game list and the 'último celebrado' behavior without adding syntax or edge cases beyond the schema, so baseline 3 applies.

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 ('el resultado de un sorteo ya celebrado') and then enumerates exactly what comes back: combinación ganadora, bote, reintegros, El Millón, escrutinio, Lotería Nacional, Quiniela, próximo sorteo. It also explicitly distinguishes itself from the sibling it is not: 'Si una jugada concreta tiene premio lo dice comprobar_premio'. An agent can route correctly without opening the schema.

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?

Provides representative user phrasings ('resultado del Euromillones', '¿ha tocado el bote?') and names the alternative for per-bet checks (comprobar_premio), plus the key default ('Sin fecha devuelve el último celebrado'). It does not clarify the boundary with the sibling 'sorteos', even though it also surfaces next-draw info, so usage guidance is clear but not exhaustive.

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