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 on the dimensions that matter for a paid endpoint: exact price ($0.01 USDC), accepted payment chains (Base or Solana), no account or API key required, failed calls not charged, and the upstream data source (DefiLlama). It omits data freshness/caching and rate limits, which would matter for a 'live' yields feed.

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?

Everything is front-loaded and telegraphic — resource, ranking, price, auth, billing policy, endpoint — with no filler. The 'Paid.' lead immediately sets the cost expectation before any other detail.

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 simple paid list endpoint with no output schema, the description covers the commercial and access prerequisites an agent needs (cost, payment chains, no key, failed calls free) plus what the data represents. The main gap is not describing the shape of each returned row or whether results are paginated beyond the limit cap.

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 documented. The description's 'by TVL or APY' restates the schema's sort semantics and adds nothing about min_tvl_usd filtering or ranking behavior, so the baseline of 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?

States a specific verb and resource ('Top live DeFi yields') plus scope ('across every chain and protocol') and ranking dimension ('by TVL or APY'), which cleanly separates it from the buy_yields_chain_* and buy_yields_protocol_* siblings that pre-scope to one chain or protocol.

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?

The 'across every chain and protocol' framing makes clear this is the global leaderboard rather than a scoped slice, which is the main selection decision in this namespace. It stops short of naming an alternative or stating an exclusion (e.g. 'for a single chain use buy_yields_chain_base'), so it is clear context without explicit routing.

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