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

The description adds materially beyond the readOnly/openWorld/destructive annotations: it states data is from real match-stats aggregates, enforces a 300-first-serve qualification threshold, clarifies season default and tour-omission behavior, and declares parallel-safety and upstream cost. Nothing contradicts the 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 definition is well-structured with clear labeled sections and front-loaded content. It loses a point because the opening line and the first 'When to use' bullet repeat the exact same sentence verbatim, adding unnecessary redundancy.

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?

Given the rich input schema, output schema, and annotations, the description still supplies the essential call-time context: defaults, optional parameter behavior, qualification threshold, and routing to sibling tools. Nothing an agent needs to decide whether and how to call this tool correctly is missing.

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 schema already documents all parameters. The description still adds value by clarifying the combined-board behavior when tour/division is omitted, the Tennis-only scope, and the 300-first-serve qualification floor tied to the underlying data, going beyond the bare parameter names.

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 names a specific resource (tennis season first-serve-won leaderboard), the metric (share of first-serve points won per player), the data source (real match-stats aggregates), and the ordering (highest pct first). This clearly distinguishes it from the many other leaderboard_* siblings.

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?

It has an explicit 'When to use' section, a 'Prefer over' statement routing away from raw call_api, and a 'Do not use when' list with named alternatives (standings, rankings_movers, player_form). The agent receives concrete selection criteria with zero inference required.

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