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 the paid model ($0.005 USDC on Base or Solana), accepted payment chains, that no account or API key is needed, and that failed calls are not charged. It omits rate limits and any note on result freshness or pagination beyond the implicit row limit.

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 and dense: 'Paid.' flags the commercial constraint first, then purpose, then price, then access terms. The telegraphic phrasing is efficient, though the trailing URL is a minor structural append that reads as an afterthought.

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 paid read endpoint with no output schema and no annotations, the description covers the essentials an agent needs to decide and call: cost, payment rails, auth posture, failure billing, and data provenance. Only the shape of returned rows is left unstated.

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 in the schema with defaults. The description's mention of APY and TVL loosely maps to the sort options but adds no syntax, units, or default behavior beyond what the schema states. 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 resource and scope: live USDG yield pools across protocols and chains, with APY and TVL sourced from DefiLlama. The token symbol in the text matches the tool name, so it is distinguishable from the buy_yields_chain_* and buy_yields_protocol_* siblings without opening a schema.

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 framing 'Where to earn yield on USDG' implies the use case, but there is no explicit when-to-use vs. when-not, and no pointer to alternatives such as buy_yields_chain_base or buy_yields_stablecoins for broader views. An agent must infer routing from the token symbol alone.

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