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

Annotations cover readOnly/openWorld, but the description adds genuinely new behavioral facts: a pay-per-call price of $0.002 USDC via x402 across Base, Solana or Arc, and that failed calls are not charged. That payment/auth detail is exactly the kind of context annotations cannot convey; only the ranking-snapshot semantics ('as published') are left vague.

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 core purpose and returned fields are front-loaded, then the exclusion and pricing follow. Two compact sentences carry a lot, though the payment-mechanics clause is dense and could be trimmed without losing decision-relevant 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?

An output schema exists, yet the description still summarizes the returned fields and discloses cost, so an agent can decide and call correctly. The only residual gap is what 'as published' means for ordering/pagination, which is minor for a read-only ranking lookup.

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% and both parameters already carry descriptions with defaults, so the schema does the heavy lifting. The description reinforces the singles/doubles choice and 'Top N' but adds no format or syntax detail beyond the schema — a baseline 3.

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?

Names a specific verb and resource — official WTA singles/doubles rankings from the wtatennis.com JSON API — and enumerates the exact fields returned (rank, player, country, points, tournaments, movement). It explicitly excludes ATP data, which disambiguates it from the other tennis siblings in the list.

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?

'Top N as published; no ATP data' gives a clear scope constraint and a negative condition, and the type parameter is described as singles (default) or doubles. However, it never points to an ATP alternative (e.g. tennisexplorer) or states prerequisites for use, so the routing guidance is incomplete.

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