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 that the call is paid, the exact price ($0.002 USDC on Base or Solana), that no account or API key is needed, that failed calls are not charged, and the upstream data source. Missing only rate limits and response shape, which is a minor gap for a read-only data endpoint.

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-loaded with 'Paid', then purpose, then pricing/payment terms, then endpoint URL — every clause carries distinct information with no repetition. Telegraphic style is intentional and readable for an agent.

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 3-optional-parameter, no-output-schema paid endpoint, the description covers cost, auth, billing-on-failure, data source, and the metric set returned. What remains thin is any sense of response structure or ordering guarantees, but that is largely acceptable given the enumerated metrics.

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 fully documented in the schema, which establishes a baseline of 3. The description adds nothing about these controls — it only lists the output metrics (APY, TVL, 7d APY change), which is return-value context rather than parameter meaning.

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: 'Live DeFi yields for berapaw: its pools across chains with APY, TVL, 7d APY change', and names the data source (DefiLlama). The protocol-scoped nature is clear enough to separate it from the buy_yields_chain_* and buy_yields_token_* siblings, though the description never explicitly contrasts itself with them.

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 through the tool name and the phrase 'for berapaw' — an agent can infer this is the per-protocol view, but there is no explicit 'use this instead of buy_yields_chain_base when you want protocol-level pools' statement. The price and 'failed calls not charged' note helps an agent decide whether to spend, which is a genuine usage signal, but it is about cost, not tool selection.

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