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 ($0.01 USDC on Base or Solana), that no account or API key is needed, and that failed calls are not charged. What it omits is any note on rate limits or response shape, though it does name the data source (DefiLlama).

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 'Paid.' then the purpose, then price, auth, billing behavior, and endpoint URL. Compact and well-ordered; the trailing raw URL is the only element that borders on boilerplate, but it is useful for debugging.

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 simple read-only, zero-required-param query tool with fully documented parameters, the description supplies what matters: what data comes back (pools, APY, TVL), the source, and the payment/auth model. No output schema exists, but the return content is described well enough at a high level.

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 sort, limit, and min_tvl_usd are already documented with defaults. The description adds only 'APY and TVL' as the concepts behind the filters, which is marginal value over the schema — 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: yield opportunities for WSTETH, covering live pools holding WSTETH across protocols and chains with APY and TVL. That token-scoped framing inherently separates it from the dozens of sibling buy_yields_token_* tools (steth, weth, wsteth variants) without ambiguity.

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?

Implies the use case (find where to earn yield on WSTETH) but gives no explicit when-to-use/when-not guidance and names no alternatives among the related siblings like buy_yields_chain_ethereum, buy_yields_protocol_lido, or buy_yields_stablecoins. The agent must infer routing from the tool name alone.

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