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

Annotations cover the safety profile (readOnly, idempotent, openWorld), but the description adds genuinely new behavior: x402 USDC pricing on Base at $0.002 per successful call, the PaymentRequired flow, symbol-to-coin resolution to the highest-ranked match, and the exact returned fields. This is far beyond what annotations provide.

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 with the use case and routing signals, and every clause carries information (limits, defaults, return shape, pricing). It is dense and slightly run-on, but no sentence is wasted.

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?

There is no output schema, and the description compensates by enumerating returned fields (price, 24h change, market cap, 24h volume, last-updated). Combined with limits, defaults, and payment handling, an agent has everything needed to call it correctly.

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 100%, so the baseline is 3, but the description adds value beyond the schema: the fallback semantics of symbol resolution ('highest-ranked coin with that symbol'), the mutual requirement of ids or symbols, and the spread of supported vs currencies. Marginal but real gain over structured fields.

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 and resource: cryptocurrency prices across thousands of coins/tokens, with volume of scope. It explicitly contrasts itself with '/v1/crypto/search' (id lookup) and 'ScrapeMole Onchain' (contract-based DEX prices), so an agent can route without opening a schema.

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?

Says when to use it (coin/token prices by id or symbol), how many identifiers each path accepts, and points to two concrete alternatives for adjacent needs. The 'call without payment to receive the PaymentRequired object' note also clarifies invocation behavior.

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