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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely valuable context beyond that: the x402 payment model, the $0.003 USDC price per successful call, payment chains (Base, Solana, Arc), and the fact that failed calls are not charged. It also enumerates returned fields, which is useful for a paid call.

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 core purpose, then return fields, then the pricing/disclaimer. Every sentence carries information, though it is on the denser side; the 'not financial advice' clause and pricing detail are somewhat boilerplate but relevant for a paid information tool.

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, so return values need no explanation, and the description still helpfully previews the payload fields. Combined with full schema coverage, readOnly/openWorld annotations, and the pricing transparency, nothing an agent needs to select or invoke this 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 description coverage is 100%, so all three parameters (limit, sortBy, window) are already documented in the schema. The description restates the ranking metrics and the day/week/month/all windows but adds no syntax or format detail beyond what the schema provides, so the baseline of 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 (Fetches) and resource (top-ranked traders on Polymarket) with the ranking dimension (overall profit or trading volume) and time scoping. This clearly distinguishes it from siblings like pm_wallet, pm_trades, and pm_holders, which deal with individual wallets or trade feeds rather than a ranked leaderboard.

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?

Usage is implied by the resource type: an agent can infer this is the tool for leaderboard/ranking queries. However, the description gives no explicit when-to-use guidance, no exclusions, and does not name alternatives like pm_wallet for a single trader's stats, leaving the routing to inference.

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