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

With no annotations, the description must carry the full behavioral burden. It usefully discloses the payment model and cost ('Price 0.01 USD per call via x402') and the fields returned, but says nothing about what happens for an unrecognized or non-notified token, whether tickers are case-sensitive, or any error/rate-limit behavior.

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?

The core capability and returned fields are front-loaded in the first clause, with context and pricing after. The regulator-deadline sentence earns its place as usage context, though the pricing note is somewhat appended rather than integrated.

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 one-parameter lookup with no output schema and no annotations, the description covers what is checked, what is returned, and the commercial terms. Only the negative-result behavior (token exists but has no notified white paper) is left unaddressed.

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% and the single 'token' parameter is fully described with examples, so the schema does the heavy lifting. The description echoes the same examples (USDC, EURC, RLUSD, USDT) without adding format or matching semantics, so it neither compensates nor detracts — baseline 3.

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?

Names a concrete verb-and-resource pair: checks whether a stablecoin/e-money token has a MiCA white paper notified in ESMA's register, and enumerates the returned facts (issuer, home state, regulator). The scope is clearly token-level, which distinguishes it from sibling mica_casp (CASPs rather than tokens).

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 an explicit business context — 'Key for EU CASPs ahead of the ESMA remediation deadline (8 Jan 2027)' — so an agent knows the situation that triggers this call. It stops short of naming an alternative or stating when not to use it (e.g. versus mica_casp or stablecoin_receipt), so no exclusions are offered.

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