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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: 'Free public API, no key' indicates no authentication required, and 'With no filters, universe is stablecoin-marked pools' discloses the default selection behavior. This goes beyond annotation coverage.

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 sentences, each serving a distinct purpose: core benchmark definition, filter options, and API access details. Information is front-loaded and there is no waste or redundancy. The structure is ideal for agent consumption.

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 tool with two optional string parameters, the description covers the data source, output contents, default behavior, and authentication requirements. It omits details like exact response format or potential rate limits, but given the tool's simplicity and strong annotations, this is adequately complete for reliable invocation.

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 both parameters are already documented as substring filters. The description echoes the same semantics ('project slug substring', 'symbol substring') without adding new meaning beyond the schema. The default universe explanation slightly enhances understanding but does not materially extend parameter semantics.

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 opens with a specific verb and resource: 'DeFi lending and stable yield benchmark from DeFiLlama Yields' and enumerates concrete outputs (top pools by APY with p25/p50/p75 APY bands, TVL, chain, pool id). This clearly distinguishes it from siblings like get_stablecoin_yield_benchmark by specifying the benchmark universe and data source.

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 clearly states optional filters (protocol and asset substrings) and explains the default universe when no filters are applied ('stablecoin-marked pools'). It does not explicitly name alternatives or exclusions, but the contextual guidance is sufficient for an agent to decide when to use this tool.

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