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

With no annotations, the description carries the full burden and does well: it discloses the data source (DeFi Llama), the return shape (top pools sorted by APY with TVL, protocol, per-chain summaries), and a per-call cost of $0.005 USDC. It omits freshness/refresh cadence and what happens when a chain has no qualifying pools.

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?

Four tight sentences, front-loaded with purpose and scope, followed by return shape, source, and cost in descending order of importance. Every sentence adds information not available in the schema.

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?

There is no output schema, but the description compensates by naming the returned fields and the per-chain summary. Combined with fully documented parameters and a stated cost, an agent has enough to call it correctly; only data freshness and failure behavior are 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 coverage is 100% and each of the three parameters has a description with defaults, so the schema does the heavy lifting. The description adds only that results are APY-sorted, which hints at how minTvl/limit shape output, but no explicit parameter guidance. 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?

States a specific verb and resource ('Scan DeFi yields') plus an explicit scope, enumerating the eight L2 chains covered. It distinguishes itself from yield_rates/lst_yields/lending_rates by domain (L2-only) but never names those siblings, so an agent must infer the boundary itself.

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 by the L2 enumeration and the APY-sorted-pools framing, but there is no explicit 'use this when / use X instead' guidance despite several adjacent yield siblings. An agent can guess when to call it, but nothing confirms the choice.

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