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

With no annotations present, the description carries the full burden and does real work: it discloses cost and payment rails, that no account or API key is needed, that failed calls are not charged, and that the data originates from DefiLlama. It does not describe rate limits, response envelope, or pagination behavior, which keeps it from 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 "Paid." so cost is seen before anything else, then payload, then pricing, then access terms, then the endpoint. Every clause carries distinct information with no repetition.

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 paid, 3-optional-param read tool with no output schema, the description covers cost, auth, failure billing, data source, and the returned fields. An agent has enough to decide and invoke correctly; only rate limits and response shape are unstated.

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 in the schema with defaults and ranges. The description adds no syntax or semantics for these filters, which is the correct baseline when the schema does the heavy lifting.

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?

"Live DeFi yields for stader: its pools across chains with APY, TVL, 7d APY change" names a specific resource and the returned metrics. The phrase "across chains" implicitly separates it from the chain-scoped buy_yields_chain_* siblings, though it never explicitly points at buy_yields_token_* or the chain tools as alternatives.

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 only implied via the protocol scope; there is no explicit statement of when to choose this over buy_yields_chain_base or buy_yields_token_steth. The payment prerequisites (no account, no API key, $0.002 USDC on Base or Solana, failures free) are the strongest usage guidance in the text.

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