Top players of a league

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds genuine behavioral context beyond that: it describes the returned record shape (player id, team, appearances, other season counters) and the important null semantics that 'a counter that is missing is zero'. It does not discuss pagination or how ties are ordered, which keeps it short of a 5.

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 verb+resource, then examples, then return shape, then the sibling routing — a sensible order. Slightly redundant in restating 'top scorers or most assists' which the stat enum description already covers, but nothing is bloated.

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?

With no output schema, the description usefully characterizes the returned player records and the zero-default rule for missing counters. Combined with the fully documented 5-parameter schema, an agent has what it needs to call this correctly; only ordering/tie-breaking behavior is left implicit.

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%, and the enum descriptions already explain every stat value, the futsal limitation, and the league_id source. The description reinforces the 'one statistic' notion with examples but adds no syntax or constraint detail beyond the schema, so the 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 and resource — 'Get the best players of a football (or futsal) league by one statistic' — with concrete examples ('top scorers', 'most assists'). It also explicitly distinguishes itself from the sibling v3_team_players, so an agent can route correctly without opening either 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?

Gives example user phrasings ('top scorer of the Premier League', 'most yellow cards') that map directly onto this tool, and names the alternative for a different intent: 'For one team's players use v3_team_players.' The when-to-use and when-to-use-something-else conditions are both explicit.

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