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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds meaningful context the annotations do not: the data source ('computed from every fight's stat sheet'), the cost ('Costs 5 credits'), and the qualification default ('default 5' fights). It doesn't state sort direction or tie-breaking, which would be nice for a leaderboard, but the added context is solid.

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?

Purpose is front-loaded ('Use for career leaderboards...') and the long parenthetical list earns its space because the enum identifiers are abbreviations that would otherwise be hard to interpret. It is dense and somewhat run-on, but every clause carries information; trimming the glosses would hurt comprehension.

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-value explanation is unnecessary, and annotations cover safety. The description covers the metric set, the filter dimensions, defaults, and credit cost. Remaining gaps are minor — sort order/ranking direction and how ties or small-sample fighters are handled.

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, but the description goes further by decoding each opaque enum token (e.g., 'sig_absorbed_per_15 (significant strikes absorbed per 15 min)', 'finish_rate (wins by KO/TKO or submission, as a share of wins)') — context the schema enum does not provide. It also reinforces the min_fights default. It adds little about limit/since/weight_class 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 combination ('career leaderboards computed from every fight's stat sheet') and immediately enumerates the eleven leaderboard metrics. This is clearly distinguishable from siblings like get_ratings, get_fighter, or get_fighter_fights, which return entities or per-fight data rather than aggregated career rankings.

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?

'Use for career leaderboards...' gives clear usage context, and the stat enumeration makes the intended scenarios obvious. It does not explicitly exclude alternatives (e.g., 'for a single fighter's stats use get_fighter'), so the when-not guidance is absent, but the use case is unambiguous.

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