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

With no annotations, the description carries the full burden and does substantial work: it discloses the paid model ($0.002 USDC on Base or Solana), that no account or API key is needed, that failed calls are not charged, and the DefiLlama data source. It does not cover rate limits, latency, or response shape, which keeps it below 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?

Front-loaded with 'Paid.' then the purpose, followed by cost, access terms, and endpoint URL. Dense and nearly waste-free, though the pricing and URL clauses could be tightened slightly.

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-optional-parameter, no-output-schema, no-annotation tool, the description supplies the pricing, access model, data source, and the fields returned. It stops short of describing the response envelope or pagination behavior that the limit parameter implies.

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 each of the three optional parameters (sort, limit, min_tvl_usd) is documented with its default in the schema itself. The description adds only the shape of the returned data (APY, TVL, 7d change), which is consistent with the sort options rather than redundant.

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 the curve-dex protocol, its pools across chains, with APY, TVL, and 7d APY change. The protocol-specific scope distinguishes it from the many sibling buy_yields_chain_* and buy_yields_protocol_* tools without needing to open the schema.

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 only implied: an agent infers 'call this when you want yields for curve-dex pools.' There is no explicit when-to-use versus the chain-level or other protocol yield tools, and no stated exclusions or prerequisites beyond the payment terms. Adequate but leaves routing to inference.

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