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

With no annotations, the description carries the full burden. It does well on the commercial/auth profile — paid at $0.005 USDC on Base or Solana, no account or API key, failed calls not charged — but says nothing about the response shape, row structure, or pagination behavior beyond the three input knobs.

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 'Paid' and the core purpose, then price, then URL, with no filler. Slightly dense listing of payment logistics, but every clause is actionable.

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, no-annotation, no-output-schema tool, it covers data source (DefiLlama), what is returned in concept (pools, APY, TVL), cost, and auth. Only the concrete return fields and pagination semantics are left implicit, which is a modest gap.

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/min_tvl_usd are already documented in the schema along with defaults. The description adds no extra semantics such as what 'apy' sorting prioritizes or how the default 100k TVL floor affects results. Baseline 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 concrete verb and resource: 'live pools holding BTC across protocols and chains, APY and TVL'. An agent can immediately tell it returns BTC yield opportunities. It does not explicitly distinguish itself from near-identical siblings such as buy_yields_token_wbtc or buy_yields_token_btcb, relying on the BTC token name to carry that discrimination.

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: you call it when you want yield on BTC. There is no explicit statement of when to prefer this over the chain-, protocol-, or stablecoin-scoped yield siblings, nor prerequisites beyond the payment note.

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