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

With no annotations, the description carries the full behavioral burden and does well: it discloses that the call is paid, the exact price and accepted payment chains ($0.005 USDC on Base or Solana), that no account or API key is needed, and that failed calls are not charged. It omits rate limits and the response shape, which keeps it from 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 'Paid.' and then the purpose, followed by pricing, access, refund terms and endpoint in short clauses. The raw URL is of marginal value for an MCP invocation, but nothing else is padded.

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?

No output schema and no annotations exist, so the description must cover return content and cost/access — it lists the returned fields (APY, TVL, 7d change) and the full payment model. Remaining gaps, such as result-page behavior or what an empty protocol yields list looks like, are minor for a zero-required-param read 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 fully documented in the schema. The description adds no extra meaning about these parameters (e.g. how min_tvl_usd interacts with chain coverage), 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 verb and resource: 'Live DeFi yields for stakewise-v3' with the data fields returned (APY, TVL, 7d APY change) and the source (DefiLlama). It is clearly distinct from the buy_yields_chain_* and buy_yields_token_* siblings by naming the protocol, though it never explicitly contrasts against the other protocol-yield siblings.

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?

Implies the use case (fetch yield pools for this one protocol) and supplies payment context, but gives no explicit when-to-use/when-not guidance relative to alternatives such as buy_yields_chain_ethereum or buy_yields_top. An agent must infer that this is the per-protocol drill-down rather than a chain-wide or ranked listing.

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