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

With no annotations, the description carries the burden well: it discloses the paid model, exact price ($0.005 USDC on Base or Solana), that no account or API key is needed, and that failed calls are not charged — unusually complete commercial context. It stops short of rate limits or freshness/caching behavior for the DefiLlama data.

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-loads the critical qualifier 'Paid.' before the purpose, then packs data contents, price, payment rails and endpoint URL into a few dense but waste-free sentences.

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?

No output schema exists, so the description usefully enumerates returned fields (base/reward APY, TVL, 7d APY change) and the data source, and it fully covers payment mechanics. Only the response envelope and pagination beyond the limit parameter remain undisclosed.

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 sort, limit and min_tvl_usd are already documented in the schema. The description adds only that results are ranked 'top pools by TVL or APY', mildly reinforcing the sort semantics without new syntax or edge-case guidance, 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?

States a specific verb and resource ('Live DeFi yields on Polygon: top pools') plus scope ('top pools by TVL or APY'), and the chain suffix distinguishes it from the dozens of buy_yields_chain_* siblings for other chains.

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 word 'Polygon' — an agent can infer this is the chain-scoped yields tool versus buy_yields_protocol_* or buy_tvl_polygon — but the description never names an alternative or states when not to use it, so routing must be inferred from sibling names.

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