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

With no annotations at all, the description does real work: it discloses that calls are paid ($0.01 USDC on Base or Solana), that no account or API key is needed, and that failed calls are not charged. That is exactly the kind of operational context annotations would otherwise supply. It stops short of describing response shape or pagination behavior for large result sets.

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?

Extremely dense with zero waste: payment flag first, then what the tool returns, then cost and access terms, then the endpoint URL. Each fragment carries distinct information and the most decision-relevant fact (paid) is front-loaded.

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 3-optional-parameter read tool with no annotations and no output schema, the description covers the gaps that matter: data source, what fields are returned, cost, payment rails, and failure billing. Only the concrete response structure is left unstated, which is a minor omission given the field list already provided.

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 already fully documented, including defaults and ranges. The description adds no extra meaning such as how sorting interacts with filtering or what units APY is returned in, so the baseline of 3 is correct.

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 states a specific resource and scope: live yield pools holding CC across protocols and chains, with APY and TVL sourced from DefiLlama. That distinguishes it from chain-wide (buy_yields_chain_*) and protocol-level (buy_yields_protocol_*) siblings without naming any of them explicitly, which keeps it just short of a 5.

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 scope statement. It never says when to prefer this over a sibling such as buy_yields_chain_base or buy_yields_top, nor does it state prerequisites beyond the payment terms. An agent can infer the use case but gets no explicit routing guidance.

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