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

With no annotations supplied, the description carries the full burden and does meaningful work: it discloses the paid/billing model, acceptable payment chains, that failed calls are not charged, and the upstream data source. It does not cover response shape, rate limits, or freshness beyond the word 'Live'.

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?

Dense, front-loaded, zero filler: cost and payment terms lead, then data content, then the endpoint URL. Every sentence carries information an agent needs before paying for a call.

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 three-optional-parameter read tool with no output schema, the description covers what the data contains, where it comes from, and the cost/safety profile of the call. Only the return shape (row structure, error behavior) is left implicit, which is minor at this complexity.

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% – sort, limit, and min_tvl_usd are all documented with defaults in the schema itself. The description adds nothing about their meaning (e.g., whether sort applies before or after limit), 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 resource (yields for the marinade-liquid-staking protocol, pool-level, across chains) and the payload fields (APY, TVL, 7d APY change, DefiLlama source). The protocol-level scoping distinguishes it from the buy_yields_chain_* and buy_yields_token_* siblings, though the description never names those alternatives explicitly.

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 context is implied by the protocol scoping plus concrete prerequisites: price ($0.005 USDC on Base or Solana), no account or API key required. What is missing is when to prefer this over siblings such as buy_yields_top or buy_yields_chain_solana for a broader view, and no exclusions are given.

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