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

With readOnlyHint already true, the description adds meaningful behavioral context: 'Counting stats are summed, rate stats averaged' clarifies how stat values are aggregated. It also discloses a non-obvious cost: 'Costs 5 credits.' No contradiction with annotations.

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?

The description is three sentences, front-loads the purpose, and packs in useful detail without fluff. Every sentence contributes: purpose, stat examples, aggregation behavior, filters, and cost.

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 ranking tool with an output schema and full parameter documentation, the description covers purpose, stat domain, aggregation semantics, filters, and cost. An agent has enough information to select and call the tool correctly without additional clarification.

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 parameters are already documented. The description adds value by giving real stat-name examples and explaining aggregation behavior for counting vs rate stats, which helps an agent understand what values the 'stat' parameter can take.

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 verb and resource: 'rank players on any weekly stat over a season,' and opens with 'Use to rank players,' which immediately communicates the tool's function. It lists numerous example stats, so an agent can distinguish this leaderboard tool from siblings like get_player_stats or get_advanced_stats.

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 description provides clear context: use it when you need player rankings for weekly stats over a season, with optional filters. It does not explicitly name alternatives or state when not to use the tool, but the 'rank players' framing gives sufficient usage guidance.

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