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 calls are paid ($0.01 USDC on Base or Solana), that no account or API key is needed, that failed calls are not charged, and that data comes from DefiLlama. It omits rate limits and result freshness/caching behavior, keeping 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 the paid flag, then purpose, then cost/auth/refund terms, then endpoint URL. Dense and mostly waste-free, though the pricing and no-API-key details are boilerplate repeated across the whole buy_* family.

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?

A three-optional-parameter read tool with no output schema; the description says what the response contains (pools, protocols, chains, APY, TVL), how it is paid for, and what happens on failure. Nothing an agent needs to decide or invoke correctly is missing.

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 fully documented in the schema itself. The description mentions APY and TVL, which loosely tie to the sort and min_tvl_usd options, but adds no syntax or defaulting behavior beyond the schema.

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 concrete resource and scope: live yield pools holding BNSOL across protocols and chains, with APY and TVL. The 'across protocols and chains' phrase implicitly separates it from the sibling buy_yields_chain_* and buy_yields_protocol_* tools, which slice the same data by chain or protocol rather than by token.

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 by the resource phrase: an agent can infer this is the tool for 'where can I earn yield on BNSOL'. There is no explicit when-to-use/when-not guidance and no naming of alternatives such as buy_yields_chain_solana or buy_yields_protocol_binance-staked-sol for related queries.

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