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

With no annotations at all, the description carries the full burden, and it does disclose the commercially critical behaviors: it is paid ($0.002 USDC on Base or Solana), requires no account or API key, and failed calls are not charged. It does not state freshness/caching of the 'live' DefiLlama data, rate limits, or what an empty result set looks like, so it is strong but not complete.

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?

Fragmented, front-loaded style ('Paid.' first, then what it returns, then price/auth/billing) lets an agent decide in one line. Nearly every fragment carries information; the trailing raw URL is the one piece that does not help an agent invoke a wrapped tool.

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 zero-annotation, no-output-schema, paid tool, the description covers the highest-risk unknowns: cost, payment rails, auth requirements, and failure billing, plus which fields come back. It omits return shape and any note about coverage/emptiness, but an agent has enough to decide and call it correctly.

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 all three optional parameters (sort, limit, min_tvl_usd) are documented in the schema with defaults, so the baseline of 3 applies. The description adds nothing about the parameters, not even that filtering by chain or token is unavailable here — which is the main semantic the agent might wrongly assume.

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 yields for meth-protocol: its pools across chains with APY, TVL, 7d APY change'. The 'across chains' phrasing implicitly separates it from the buy_yields_chain_* siblings and the protocol name separates it from buy_yields_token_*, but the description never states that routing rule explicitly.

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 subject matter: an agent can infer it should be called when it wants yield data for the Meth protocol specifically. There is no explicit when-to-use/when-not, no mention of the chain- or token-scoped variants as alternatives, and no guidance on choosing between min_tvl_usd thresholds.

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