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

Goes well beyond the readOnly/destructive annotations: it discloses the payment model ($0.99 x402, Builder/Pro key, 1 free MCP trial/day), the attribution method, the exclusion rules (facilitator pass-through, circular-flagged wallets), and that unresolved wallets surface as one explicit unattributed row. It also reveals two non-obvious return behaviors — the per-day recipient-completeness flag and the retroactive_exclusion_caveat with its 2026-07-28 cutoff.

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?

Dense but well-organized: scope and methodology come before the caveats, and each clause carries real information. The opening rhetorical question is slightly wasteful and the payment sentence is long, but there is little true padding for a tool with this much non-obvious behavior.

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?

With no output schema, the description still tells the agent what comes back — a ranked provider list, an explicit unattributed row without dollar values, a completeness flag, and a retroactive caveat marker — plus cost and access. Nothing material needed to interpret or price the call 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 top, window, and api_key are already fully documented in the schema (ranges, defaults, and the trial/x402 behavior of omitting the key). The prose adds no syntax or format detail beyond that, 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?

The opening 'Who earns the most' plus the explicit methodology ('Resolved by payTo wallet attribution, not by counting events') makes clear this is a provider-revenue leaderboard. It implicitly separates itself from a full-ecosystem census tool, but never names a concrete sibling like get_market_summary or get_best_value_provider, so the differentiation is inferred rather than stated.

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 defines the applicable universe ('ATTRIBUTED universe only, never the full-ecosystem census'), which implicitly tells the agent when this answer is valid, but it never says when to pick this over the sibling revenue/market tools or what prerequisites exist beyond payment. Usage 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.