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

Annotations already establish readOnly/openWorld safety. The description adds genuine context: no account required, and the behavior when a draw has no escrutinio yet (it says so along with the usual publication time). It also enumerates the returned prize breakdown, useful since there is no output 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?

Front-loaded with the core action and value, then progressively adds examples, game list and edge-case behavior. It is long but nearly every sentence carries information; minor density loss from the clustered example questions.

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?

Covers the game whitelist, the two input families, the no-account fact, and the pending-escrutinio case, which is sufficient for a 7-parameter read-only tool whose return fields are listed in prose. Lacks only explicit sibling routing.

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%, so baseline is 3, but the description adds real mapping value: which parameter to populate per game family (decimos for Lotería Nacional/Navidad/El Niño, apuestas for number games) and that values read from a photo are accepted. That goes beyond the field-level schema text.

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 precise verb (comprueba) and resource (un décimo o una apuesta concreta) with scope: whether it has a prize and how much (bruto, retención, neto, categoría, plazo). The framing around the user's own play distinguishes it implicitly from siblings like resultado_sorteo, which only surface draw outcomes.

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?

Gives concrete trigger questions («tengo el 45433, ¿me ha tocado?») and per-game instructions (Lotería Nacional → decimos; juegos de números → apuestas), plus a note that photo-read numbers work. It never names an alternative or a when-not condition, so the routing against resultado_sorteo/sorteos 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.