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 the price ($0.01 USDC), accepted payment chains (Base or Solana), that no account or API key is required, that failed calls are not charged, and that the underlying data is DefiLlama. Missing are rate limits, data freshness/latency, and any hint of the response shape beyond the listed metrics.

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?

It is short and front-loaded: the paid status and resource come first, then pricing/payment, then the endpoint URL. The one-word 'Paid.' is terse to the point of being slightly cryptic, but the rest of the sequence is efficient with no filler.

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 annotations and no output schema, the description covers the essentials an agent needs to commit money: cost, payment rails, failure billing, and the metrics returned. Only the absence of any output-structure or pagination cue keeps it from being fully complete.

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%, so sort, limit, and min_tvl_usd are already documented with defaults in the schema. The description adds nothing about parameter behavior (e.g., whether min_tvl_usd filters out pools entirely or how sorting interacts with limiting), so the 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?

The description names a specific resource and scope: live DeFi yield pools for the sky-lending protocol across chains, with the fields returned (APY, TVL, 7d APY change). That distinguishes it from the chain-level and token-level yield siblings by implication, but it never explicitly contrasts with buy_yields_top or buy_yields_chain_*.

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?

There is no when-to-use direction: nothing says to pick this over buy_yields_top, a chain-level tool, or a token-level tool when the agent wants protocol-specific yields. The payment and access notes tell the agent how it will be charged, not when to select the tool.

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