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

Annotations only declare readOnlyHint and openWorldHint; the description adds material behavioral facts the annotations do not cover — an x402 payment of $0.05 USDC per successful call, and explicitly that errors are not charged. It also discloses the risk-tier heuristics (outlier APY, thin TVL, reward-heavy, IL exposure). Missing only rate limits or data freshness.

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?

Four dense sentences with no filler, though the lead position is given to the pricing notice rather than the tool's core purpose, which is arguably the more important orientation for an agent. Everything after that is information-bearing.

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 carries more burden, and it covers cost, filter axes, risk semantics and provenance. It stops short of describing the shape of a returned pool row (APY field, TVL, tier label) or data freshness, which for a paid query tool would close the remaining gap.

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 the baseline is 3, and the description earns above it by explaining what the risk tiers actually mean (outlier APY, thin TVL, reward-heavy, IL exposure) — semantics the enum in the schema does not convey. It also confirms the filter axes match the parameters.

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+resource (find top DeFi yields) with concrete scope: 16k+ pools, filtered by asset, chain, minimum TVL and risk. No sibling tool overlaps this domain, so differentiation is unnecessary, and the data source (DefiLlama) pins down exactly what is returned.

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 establishes context (finding yields for a given asset/chain/risk) but never says when to reach for this tool versus another, nor any preconditions or exclusions. Usage is implied rather than stated, which is the definition of a 3.

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