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

With no annotations at all, the description carries the full burden and does well: it discloses that the call is paid ($0.01 USDC on Base or Base or Base), that no account or API key is needed, that failed calls are not charged, and that data comes live from DefiLlama. It does not describe response shape or rate limits, which keeps it short of 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-loaded with scope, then payment terms, then endpoint; nearly every sentence earns its place. The trailing raw URL is mildly redundant but not wasteful enough to penalize further.

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 read-only query tool with three fully documented optional parameters and no output schema, the description covers scope, data source, cost, and auth requirements. It notes APY and TVL as the returned fields, though it could say more about what a pool row contains.

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. The description adds no filtering or formatting nuance beyond that, so the 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?

"Live pools holding RETH across protocols and chains, APY and TVL" states a specific resource and the exact data returned, so an agent can distinguish it from the sibling token-yield tools such as buy_yields_token_steth or buy_yields_chain_base 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 use case (find where to earn yield on RETH) is implied clearly, but there is no explicit when-to-use versus alternatives such as buy_yields_protocol_* or buy_yields_chain_*, nor any statement of prerequisites. Usage is inferable but not routed.

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