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

With no annotations provided, the description carries the full behavioral burden and does well: it discloses that the call is paid, costs $0.005 USDC on Base or Solana, requires no account or API key, charges nothing on failure, and uses DefiLlama data. It does not cover rate limits or the exact payment mechanics, which keeps it from 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?

The description is short and front-loaded, opening with the key fact that the call is paid, then giving the data scope, price, access conditions, failure policy, and endpoint URL. Every sentence contributes useful information for an agent deciding whether and how to call it.

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?

For a three-parameter paid data endpoint with no output schema and no annotations, the description is quite complete: it names the returned data fields, the upstream source, cost, payment networks, authentication posture, and failure charging policy. A brief note on response shape or rate limits would make it fully self-contained.

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 sort, limit, and min_tvl_usd parameters are already documented in the input schema. The description mentions APY and TVL data but does not add syntax, defaults, or filtering semantics beyond what the schema provides, making the baseline 3 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 states a specific data resource: live DeFi yields for Vesper, including pools across chains with APY, TVL, and 7d APY change. This clearly distinguishes it from sibling protocol-yield tools such as buy_yields_protocol_aave-v3 or buy_yields_protocol_lido.

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 phrase 'for vesper' implies this is the tool to use when seeking Vesper protocol yields, but there is no explicit guidance about when to prefer chain-level, token-level, or top-yields siblings. The payment and access notes help the agent decide whether it can call, but not which sibling to choose.

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