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

With no annotations, the description carries the full burden and does well: it discloses that the call is paid, the exact price ($0.005 USDC on Base or Solana), that no account or API key is needed, that failed calls are not charged, and that the data is DefiLlama-sourced. It omits rate limits, freshness/caching, and response shape, keeping it short of a 5.

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 and front-loaded: cost and data scope come first, then payment mechanics, then the endpoint. Every clause carries information, though embedding the raw URL in prose is slightly awkward and the '$0.005' style is repeated by implication in the payment sentence.

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 required parameters and a fully documented schema mean the description only needs to cover provenance and payment, both of which are covered in detail. Missing only return-shape hints, though there is no output schema, and freshness of 'live' yields is not quantified.

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% and all three optional parameters (sort, limit, min_tvl_usd) have documented defaults and ranges in the schema. The description adds nothing about them, so 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 for hyperliquid-earn') and enumerates the returned fields (APY, TVL, 7d APY change), which clearly differentiates it from the other buy_yields_protocol_* siblings that target different protocols.

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?

Payment terms and data source give operating context, but the description never says when to pick this protocol-scoped tool over buy_yields_chain_*, buy_yields_token_*, or buy_yields_top, nor does it state any exclusion or prerequisite. Usage has to be inferred from the protocol name alone.

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