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

Annotations already establish readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the returned fields (base + reward APY, 30-day mean APY, TVL, IL risk, link) and a per-call cost of $0.0028 USDC via x402, which is important for an agent budgeting calls. It omits freshness/latency and pagination behavior.

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?

Three compact clauses: scope, capabilities, return/cost. It is front-loaded on the resource and maximum density with no filler sentences.

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 no output schema, the description correctly compensates by listing return fields, and it discloses the x402 cost. For a 7-parameter, all-optional read tool this is nearly sufficient; only freshness/rate-limit context and a note on the limit parameter are missing.

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 already 86%, and the description still adds meaning by enumerating the filterable dimensions (chain, protocol, token symbol, stablecoin-only, minimum TVL) and both sort modes. Only 'limit' is left unaddressed, but the baseline for high coverage is 3 and this description clearly exceeds it.

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 yield pools, 16,000+ of them) and its differentiators (APY base+reward, 30-day mean, IL risk), which conceptually separates it from defi_tvl, defi_fees and defi_dexs. However, it never explicitly names or contrasts with those siblings, which share overlapping filter dimensions like chain and protocol.

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 only implied: the filter list and 'sort by APY or TVL' suggest this is for finding top-yielding pools, but there is no explicit when-to-use, no when-not-to-use, and no pointer to alternatives such as defi_tvl or staking_rates. The cost note is helpful but is not usage guidance.

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