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

Beyond the annotations (readOnly, openWorld, idempotent), the description discloses additional behavior: the cost per call, payment challenge mechanism, and the fact that unpaid or no-data calls cost nothing. It also clarifies null name handling, adding transparency not present in 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 description is moderately detailed but each sentence serves a purpose: it covers the core function, a use case, a data nuance (null names), and cost/payment details. The structure is logical, starting with the primary purpose and then adding practical context.

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?

The description provides a clear picture of the output (rank, pseudonym, display name, wallet address, USDC amount) and includes operational details like cost and HTTP route. While it doesn't specify an exact response format, the information is sufficient for an agent to understand what the tool returns and how to use it.

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?

The input schema already provides full parameter descriptions (limit, metric, window) with examples. The description reinforces these by mentioning 'traded volume or realised profit' and '1d, 7d, 30d or all-time window,' but adds no new semantics beyond the schema. Since schema coverage is 100%, baseline score of 3 is appropriate.

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 clearly states the tool's function: retrieving a public trader leaderboard from Polymarket, with specific metrics (volume or profit) and time windows. It distinguishes itself from sibling tools by focusing on leaderboard data rather than individual markets or trades.

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?

The description explicitly suggests when to use the tool ('Use it to find who is moving size on the venue') and provides actionable context like the HTTP route and cost. While it doesn't explicitly contrast with alternatives, the purpose is clear enough for an agent to select it appropriately.

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