generate_test_ibans

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

With no annotations, the description carries the burden and does well: it discloses the IBANGEN_API_KEY auth requirement, the paid-plan gating on the bank parameter, seed-based determinism, and the safety-critical constraint that output is test-only. It does not describe rate limits, error behavior, or failure modes when a country/bank combination is unsupported.

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?

Four short sentences with zero filler, opening on the core purpose and then walking parameters and the safety caveat in priority order. Every sentence adds new information.

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 values need not be explained, and the description covers purpose, auth, plan gating, and the safety constraint. The only real gap is the undocumented quantity parameter and unstated behavior for invalid country/bank inputs.

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 0%, so the description must compensate, and it explains three of four parameters: country format ('Germany' or 'UK'), the repeatability semantics of seed, and the plan restriction on bank. The quantity parameter is never mentioned, leaving one undocumented at 0% coverage.

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 precise verb and resource ('Generate synthetic, checksum-valid test IBANs') and scopes it to QA/development. This is unmistakably distinct from the siblings lookup_bank and validate_ibans, so an agent can route without opening any 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?

Clearly frames the context ('for QA and development') and adds a hard exclusion ('must never be used for payments'), which is genuinely useful routing guidance. It does not explicitly name when to prefer a sibling (e.g., use validate_ibans to check real IBANs), so it stops short of full alternative coverage.

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