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: it discloses cost, accepted payment chains, absence of authentication, and that failed calls are not billed, plus the upstream data source (DefiLlama). Remaining gaps are rate limits and response shape beyond the listed fields, which keeps it off 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-loads the paid flag, then scope, then returned fields, then payment/auth/error terms, then the endpoint URL. Every fragment earns its place; nothing is repeated or padded.

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-required-parameter read tool with fully documented schema, the description covers purpose, data provenance, cost, auth and billing behavior, so an agent can call it safely. Missing are pagination/row-count expectations and the exact response envelope, which matter slightly given no output schema exists.

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 with defaults and ranges. The description only echoes the sortable fields (APY, TVL) as output attributes, adding no syntax or edge-case meaning for the parameters themselves.

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 resource and scope: live DeFi yields for the apyx-protocol, its pools across chains, returning APY, TVL and 7d APY change. The protocol-level framing contrasts implicitly but clearly with the chain-scoped (buy_yields_chain_*) and token-scoped (buy_yields_token_*) siblings.

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?

Gives the decision-relevant context (paid, $0.002 USDC on Base or Solana, no account or API key, failures not charged) and the protocol-level scope implies when to pick this over chain- or token-level yield tools. It stops short of explicitly naming an alternative tool or a when-not-to-use condition.

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