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

Beyond readOnlyHint and openWorldHint, the description discloses the data source (DefiLlama), the ordering (by APY), the returned fields (base vs reward APY, 30-day mean, IL risk, TVL), outlier removal, a 15-minute cache, and the exact cost and payment rail ($0.010 via x402 USDC on Base or Solana). These are material traits an agent cannot get from the annotations.

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 dense sentences with the core purpose and filters front-loaded, followed by result contents and then cost/caching. The opening restates the title almost verbatim, which is the only real waste.

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 read-only, no-output-schema tool with 7 optional parameters, the description covers data source, sort order, returned metrics, caching and payment requirements well. Minor gaps remain around default result size, pagination, and what happens on payment failure.

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 86%, so the schema already carries most parameter meaning. The description echoes chain, symbol, stablecoin and min TVL filtering but says nothing about the 'project' or 'limit' parameters, and adds no format or interaction detail beyond the schema.

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 concrete resource and verb-like action: 'Top DeFi pools from DefiLlama filtered by chain, token symbol, stablecoin-only and minimum TVL, sorted by APY.' That is specific enough for an agent to distinguish it from siblings like token_price or token_risk, though no sibling is named explicitly.

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 listed filters and the 'sorted by APY' behavior, so an agent can infer this is the yield-shopping tool. However, there is no explicit when-to-use/when-not guidance and no pointer to an alternative such as arbitrage or token_report for related questions.

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