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 behavior not in the annotations: no account required, no-argument default scope, and no number prediction.

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-loads purpose and example queries before the negative boundaries and the game list. The 12-game enumeration is long but earnable, since it defines the valid domain of the 'juego' parameter.

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, so the description takes on the burden and does state what comes back (jackpot, price, closing time), the default scope, and the exclusions. Minor gap: no mention of refresh cadence beyond 'al minuto' or any result-shape caveats, but nothing an agent needs to call it is missing.

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 operational meaning beyond the schema: with no arguments it returns today plus the coming days for all games, and the explicit instruction not to compute the date ('pásalo tal cual') is extra guidance the schema does not carry.

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 (upcoming draws with jackpot, price and closing time) and names the exact data domain (state lotteries in TuLotero). It also draws a clean boundary against the sibling resultado_sorteo by declaring it does NOT return already-held draws or predict numbers.

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 user-question exemplars that map directly to the tool (jackpot amounts, weekend draws, is there a Bonoloto today, closing time for La Primitiva), plus the no-argument default. The explicit exclusion of past results routes the agent to resultado_sorteo when appropriate.

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