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

With no annotations supplied, the description carries the full burden and does well: it discloses the paid model ($0.002 USDC on Base or Solana), that no account or API key is needed, and that failed calls are not charged. It omits rate limits and per-call throttling, but the cost and auth profile an agent most needs before paying are covered.

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 the critical 'Paid.' signal, then purpose, then pricing/auth, then endpoint. Sentences are short and each carries a distinct fact. The raw URL is somewhat boilerplate but arguably useful for identifying the paid service.

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 read tool with no output schema, the description supplies the data source (DefiLlama), the returned fields, cost, and payment chains. Missing only return-shape/pagination detail, which is a minor gap given every parameter is documented in the 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 inline with defaults, so the baseline of 3 applies. The description adds adjacent value by naming the returned metrics, but does not explain how sort or min_tvl_usd map onto them beyond what the schema already says.

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 compound-v2') and enumerates the payload: pools across chains with APY, TVL, 7d APY change. The protocol-scoped naming plus the 'its pools' phrasing separates it from the sibling chain, token, and other-protocol yield tools.

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 scope implies when to use it (you want compound-v2 pool yields specifically), but there is no explicit routing guidance such as 'use buy_yields_protocol_compound-v3 for newer markets' or 'use buy_yields_chain_* to sweep all protocols on a chain'. With hundreds of near-identical yield siblings, an explicit alternative would have earned a higher score.

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