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

With no annotations, the description carries the full behavioral burden and does well: it discloses that the call is paid ($0.01 USDC on Base or Solana), requires no account or API key, is not charged on failure, and that data comes from DefiLlama. It omits response shape/pagination details, but the cost, auth and billing-failure traits are exactly the non-obvious behaviors an agent needs.

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 'Paid.' flag, then states what the data is, the price, the auth model, the billing guarantee, and the endpoint — every sentence is a fact an agent would otherwise have to guess. No filler or 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 read-only, zero-required-param data endpoint with no output schema, the description covers data content, cost, payment chain, auth and billing semantics. Minor gaps remain: no mention of what an empty/unknown-protocol result looks like or whether results are paginated beyond the limit parameter.

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% and all three parameters (sort, limit, min_tvl_usd) are documented in the schema with defaults, so the description adds nothing about them. Baseline 3 applies since 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?

Names a specific verb and resource ('Live DeFi yields for jagpool-staked-sol') and enumerates the returned fields (pools across chains, APY, TVL, 7d APY change). The protocol slug in the description matches the tool name, so an agent can tell it apart from the many sibling buy_yields_protocol_* tools without opening the schema.

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 naming (per-protocol yield lookup) and prerequisite/payment details are given, but there is no explicit when-to-use versus alternatives — e.g., nothing says to prefer buy_yields_chain_solana for chain-wide yields or buy_yields_protocol_jpool for the sibling protocol. The agent must infer the routing.

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