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

Beyond the readOnly/openWorld/idempotent annotations, it discloses the result cap (up to 25 matches), the ordering rule (CoinGecko relevance), the exact returned fields, and the payment model ($0.001 per successful call via x402 USDC on Base). Crucially it reveals the unauthenticated behavior: calling without payment returns a PaymentRequired object rather than an error, which the agent would otherwise not know.

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, front-loaded with the purpose and examples, then results, then the payment caveat. Every clause carries information the agent needs; nothing is filler or restated from the title.

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?

With no output schema, the description compensates by enumerating the returned fields and the match ordering, and it covers the non-obvious paid-invocation path. An agent has everything needed to call it correctly and interpret the response.

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 both parameters are already documented, setting the baseline at 3. The description adds ordering semantics (CoinGecko relevance) and result-shape meaning that the schema does not express, plus echoes the 25-result ceiling, putting it slightly above baseline.

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: resolving a coin/token name or ticker to its CoinGecko id, with concrete examples ("solana", "pepe", "usdc"). It also ties its output to the downstream consumer (/v1/crypto), which separates it cleanly from sibling tools like quote or search.

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 frames this as an id-resolution step for /v1/crypto, giving a concrete condition for use. It does not, however, name an alternative sibling (e.g., a generic search tool) or state a when-not case, so it stops short of full routing guidance.

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