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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true, so the safety profile is covered. The description adds value beyond that: it declares the tool is tennis-only (despite the game enum offering six titles), states the upstream cost of 1, and enumerates the valid filter values. It stops short of describing result shape or any rate/limit behavior, but the output schema covers returns.

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 resource and its outputs, then structured into clearly labeled use/prefer/avoid sections, with a compact trailing line for the tennis-only constraint and cost. Slightly verbose with repeated filter enumerations, but every block carries routing or constraint information.

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 read-only aggregate tool with a full output schema and 100% parameter coverage, the description supplies everything an agent needs: what it returns, when to choose it, which siblings to prefer, the tennis-only scope, and the cost. No material gap remains.

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%, so every parameter is already documented, including the surface enum and yearFrom/yearTo bounds. The description restates the same filter set (surface Hard/Clay/Grass/Carpet, yearFrom/yearTo) without adding format or semantics 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+resource (tennis player career statistics) and enumerates exactly what aggregates are returned: W/L, win%, titles, Grand Slam/Masters titles, per-surface and per-level breakdowns. It also explicitly names the sibling tools it is not (player_profile, player_matches), so an agent can distinguish it without opening another 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?

Contains explicit 'When to use' examples, a 'Prefer over' section naming player_profile and player_matches with the reason each differs, and a 'Do not use when' section routing the match log to player_matches and ranking-over-time to player_rankings_history. Nothing is left to inference.

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