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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses the $1M TVL floor, the 50-result cap, that APY is a DefiLlama estimate split into base and reward with often-temporary reward APYs, plus the exact cost model ($0.002 USDC per successful call via x402, failed calls free). The data-reliability caveat and billing behavior are exactly the kind of context annotations cannot carry.

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?

Purpose and constraints are front-loaded in the first sentence, followed by data-quality caveats and billing terms. It is dense and semicolon-heavy with some mandatory legal/attribution boilerplate, but every clause carries actionable information and none is redundant.

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?

With an output schema present and annotations covering the safety profile, the description supplies cost, scope, result cap and APY caveats, which is nearly everything an agent needs. The one small gap is that 'sorted by APY' does not state direction, and multi-value filter behavior is unaddressed.

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 all five parameters are already documented in the schema. The description restates chain/project/symbol filtering and the $1M TVL floor without adding syntax or format detail beyond the schema, 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 ('DeFi yield pools from DefiLlama') and pins down the key scoping constraints: minimum $1M TVL, sorted by APY, filtered by chain/project/symbol, capped at 50. This is clearly distinguishable from siblings like defi_tvl, defi_stablecoins or dex_pools without opening any 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 description implies when the tool is useful (yield/APY discovery filtered by chain, project or symbol) but never states when to prefer it over related siblings such as defi_tvl or dex_pools, nor any exclusions. Usage is inferable but not spelled out.

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