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

With zero annotations, the description carries the behavioral burden and does well: it discloses that the call is paid ($0.002 USDC on Base or Solana), requires no account or API key, and that failed calls are not charged. It does not describe response shape, row caps beyond the schema's limit, or rate limits, so it stops short of full transparency.

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?

Telegraphic but front-loaded: 'Paid.' signals cost immediately, then what the data is, then pricing, then the endpoint URL. Every clause carries information; the stylistic fragments are dense rather than wasteful.

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, no-annotation, no-output-schema data tool, the description covers cost, auth, and the returned metrics well. It omits what the response envelope looks like (fields per pool, pagination beyond limit) and whether the charge applies per-call or per-request-set, which matters for a paid tool.

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. The description adds no parameter-level detail (e.g., that sort=apy interacts with min_tvl_usd filtering, or that all params are passed as strings), so 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?

The description names a specific resource ('DeFi yields for resupply: its pools across chains') and enumerates the returned fields (APY, TVL, 7d APY change, DefiLlama source), so an agent knows exactly what data it gets. It does not explicitly contrast itself with the many sibling buy_yields_protocol_* tools; differentiation relies on the protocol name embedded in the description and tool name.

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 implied: call this to get yield/TVL data for the Resupply protocol. There is no explicit when-to-use guidance, no mention of when to prefer a chain-level or top-level yields sibling, and no stated prerequisites beyond 'no account, no API key'. Adequate but leaves routing to inference.

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