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 paid access at $0.002 USDC on Base or Solana, no account or API key required, and that failed calls are not charged. It omits how payment is actually transmitted and whether results are paginated or rate-limited, which keeps 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?

Front-loaded with the core capability, followed by payload fields, pricing, and access terms in tight succession. Minor waste in the near-duplicative access assurances and a raw endpoint URL that adds little for an agent, but nothing is padded.

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-param read tool with no annotations or output schema, the description covers what is returned (APY, TVL, 7d change), the data source, cost, and access constraints. The main gap is the shape of the response — pool list versus aggregate — which matters given there is no output schema.

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 coverage is 100% and each of the three optional parameters (sort, limit, min_tvl_usd) is documented in the schema, so the description adds no per-parameter meaning. Baseline 3 is appropriate since the schema does the work. The description does imply the result set is pool rows with a TVL floor, which loosely aligns with the filtering params.

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 resource and dataset: live DeFi yields for the justlend-v1 protocol, with pool-level APY, TVL and 7d APY change from DefiLlama. An agent can tell this returns protocol-scoped pools rather than chain-scoped data. It does not explicitly name the sibling families it differs from (buy_yields_chain_*, buy_yields_top), leaving the differentiation to the tool name.

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 context is implied by the protocol scoping, and the description adds practical selection signal by disclosing that this is a paid call, its price, and that failures are free. But it never states when to prefer it over the chain-wide or token-level yields siblings, nor any prerequisite for calling it.

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