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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds meaningful extra behavior: it uses the official TuLotero scrutiny service, requires no account, accepts numbers read from a photo, and returns specific prize details. This goes beyond the annotation baseline without contradicting it.

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?

The description is dense but efficient: the opening clause immediately states purpose and output, and each sentence contributes: how to pass numbers, games supported, photo-read input, and no-account requirement. No filler or repetition of schema-level minutiae. Slightly long first sentence but entirely information-bearing, so it earns its place.

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?

For a tool with 7 params, rich schema annotations, and no output schema, the description covers the key operational context: supported games, input shape per game type, draw specification via cuando, and required authentication status. It does not describe error situations or rate limits, but those are not critical for a read-only check tool, especially given annotations cover the safety profile.

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 baseline is 3, and the description adds valuable mapping between game types and parameters (décimos vs apuestas) plus clarifying scope for cuando ('Omítelo para el último celebrado. Pásalo tal cual; no calcules tú la fecha'). This adds meaning beyond the schema's individual parameter descriptions.

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: 'Comprueba ... si un décimo o una apuesta tiene premio' and enumerates the exact output fields returned (bruto, retención, neto, categoría, plazo de cobro, combinación ganadora). It also clearly distinguishes itself from siblings like resultado_sorteo and como_se_juega by focusing on prize checking with official TuLotero scrutiny.

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 context for when to use this tool: when you have décimo or apuesta numbers and want to know if it won, and it explicitly lists supported games. It also gives input routing guidance ('Lotería Nacional... pasa los números de décimo' vs 'Juegos de números: pasa cada apuesta'). However, it never explicitly says when NOT to use it or names sibling alternatives.

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