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

Annotations already declare this as a read-only, idempotent, non-destructive lookup, so the description only needs to add semantics — and it does, by saying the result contains the player's rank and season points per league and that event_id switches from season to tournament standing. It does not describe what happens for an empty or unranked player, but that is a minor gap given the annotation coverage.

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?

It is only two sentences with no filler, and the default (no scope) case is stated first. However, the description is in Spanish while the schema and parameters are in English, and the second sentence is a dense run-on that packs three conditions into one clause, which slightly hurts readability.

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 three-optional-parameter read tool with no output schema, the description covers both invocation modes and indicates the returned content (rank and points). A short note on result shape or behavior when the player has no leagues would make it complete.

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 the baseline is already satisfied; the description goes further by explaining the dependency between scope=league and league_id, and that event_id selects a tournament standing. It does not add format details, but the schema already supplies enums and UUID patterns.

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 resource (fantasy standings for the player) and clearly separates two modes: without scope it returns the player's leagues with their rank and season points, with scope it returns that specific classification. It is easy to distinguish from get_fantasy_season or get_fantasy_field, though it does not name those siblings explicitly.

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?

It gives concrete when-to-use logic: omit scope to get all of the player's leagues, supply scope (global, country, club or league + league_id) to get that one ranking, and add event_id for a tournament standing instead of the season. It does not mention when to prefer sibling tools such as get_fantasy_season.

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