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

With no annotations, the description still discloses two important behavioral traits: the DefiLlama data source and the 0.002 USDC x402 payment cost. It does not mention data freshness, ranking order, or read-only nature, leaving some behavioral context implicit.

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?

Two sentences with no waste. The purpose is front-loaded, followed by the payment cost, making the definition easy to scan.

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 simple data-retrieval endpoint with no output schema, the description sketches the return shape, source, and cost. It still omits key context such as data freshness, exact output fields, and how limit affects the ranking.

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 only 50%: paymentProof is documented in the schema, but limit has no description in either the schema or the tool description. The word 'ranked' faintly implies a top-N list, but the description does not compensate for the missing limit 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 states a precise metric and grouping: circulating stablecoin supply per blockchain, ranked, with each chain's share of the total. It is clear what the tool returns, though it does not explicitly contrast with the nearby stablecoin_pegs sibling.

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 explains what the tool returns but gives no guidance on when to use it versus alternatives such as stablecoin_pegs or chain_tvl. The only usage detail is the payment cost.

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