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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, but the description adds genuinely useful non-schema behavior: the TVL >= $10M inclusion floor, the DefiLlama source, and that each call costs $0.01 USDC via x402 on Base. Payment/auth requirements are exactly the kind of context annotations don't cover.

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?

Front-loaded and information-dense, but the payment terms are stated twice ('$0.01 USDC x402 Base' and '[x402: 0.01 USDC per call on Base]'), which is pure redundancy. The core differentiator sentence is also crammed with two ideas at once.

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, single-parameter tool with no output schema, the description covers source, cost, filtering, and the ranking logic an agent needs to decide relevance. The main gap is that it never describes the shape of the returned ranking or the expected 'input' payload.

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% with a single loosely-specified 'input' parameter, so the schema baseline applies. The description adds nothing about what product parameters the input should carry, leaving the payload format ambiguous in both places.

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+resource (stablecoin DeFi yields ranked) plus the differentiator (risk outlier detector based on APY vs class median), which separates it from siblings like defi_llama_tvl_ranking and stablecoin_supply. It never explicitly names a sibling to route against, so it stops short of a 5.

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?

Gives a qualifying constraint (TVL >= $10M) and sourcing/cost facts, but never says when to choose this over defi_llama_tvl_ranking, stablecoin_supply, or top_crypto. No when-to-use or when-not-to-use guidance is present.

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