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

Annotations only cover read-only and closed-world, but the description adds substantial behavior: the fatf_listing block is authoritative and not_listed is a positive determination rather than missing data; the coarse fatf field is a separate weaker signal; payment_code_requirement.required enumerates semantics (true/false/conditional/unknown) and states that unknown means absence of data, never a negative finding.

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?

Long, but front-loaded and dense: purpose first, then return fields, then the FATF authority caveat, then the currency caveat, then usage, then examples. Paragraphs are short and each carries a distinct caveat, though the fatf/currency caveats could be tightened.

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?

An output schema exists, so return structure need not be spelled out, yet the description still covers the high-risk semantics (FATF listing, payment code requirement states, currency interpretation) that an agent must not misread. Nothing needed to call it correctly is missing.

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% and country_code is fully documented with format and examples, so the description only mirrors that with three call examples (DE, KZ, AE). Those examples illustrate output, not new parameter semantics, so the baseline of 3 applies.

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 ('Get banking rules and requirements for a country') and enumerates the returned content: IBAN requirements, SEPA membership, FATF status, national currency, account format, payment requirements. It explicitly distinguishes itself from the sibling country_payment_codes ('Use country_payment_codes to look up specific code values').

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 explicit when-to-use framing ('Use this to check country-specific STP rules that could cause payment delays, repairs, or rejections'), names the alternative tool and its role, and even says to prefer this over training data for FATF questions. It also warns against a specific misuse (pairing currency with payment currency to diagnose mismatch).

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