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

Annotations already declare readOnlyHint/destructiveHint/openWorldHint, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond the annotations: counting stats are summed while rate stats are averaged, and each call costs 5 credits — both material to how an agent plans usage.

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 use case, then the stat vocabulary, then aggregation rule and filters, closing with cost. The long stat enumeration is long but earns its place by preventing schema-opening reconnaissance; only minor trimming is possible.

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 an output schema present, return values need not be described. The description covers the critical caller-facing facts — stat vocabulary, aggregation behavior, filterable dimensions, and credit cost — leaving only minor gaps like pagination/limit semantics, which the schema already documents.

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 3. The description exceeds it by expanding the 'stat' parameter from three examples into a large enumerated vocabulary (~130 more) and by explaining the aggregation semantics of the stat value itself; it does not, however, explain limit or season_type defaults beyond what the schema states.

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 opens with a specific verb+resource ('rank players on any weekly stat over a season') and enumerates representative stat columns, so the agent knows exactly what the tool produces. It does not explicitly contrast itself with the closest sibling, get_player_stats, which returns raw stat lines rather than rankings, leaving that distinction to inference.

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 phrase 'Use to rank players' gives implied context, and the filter list (position, team, minimum games) hints at narrowing scenarios. However, there is no when-not guidance and no named alternative for retrieving individual player stats instead of rankings, so the agent must infer the boundary with get_player_stats.

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