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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does so thoroughly. It explains the ISO 7064 check-digit computation, left-padding of the account, defaulting of the reserved digit, and the important edge case that unknown bank codes still produce a structurally valid IBAN with bankName null.

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 concise sentences with no filler: the first states the core action, the second defines the output format and construction rules, and the third covers edge-case behavior. Information is front-loaded and every sentence earns its place.

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?

The description covers format, algorithm, parameter behavior, and edge cases, which is strong for a tool with no output schema. It never explicitly states the full return shape beyond mentioning bankName, but the IBAN format is fully specified and the key behavioral caveats are present.

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. The description adds meaningful context beyond the schema by explaining how the reserved digit defaults to 0, how account numbers are padded, and how the bank name resolution behaves for unknown codes.

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?

The description opens with a specific verb and resource: 'Builds a Turkish IBAN from a 5-digit bank code and account number.' It clearly distinguishes the generation/construction action from sibling validation tools like iban_validate, so an agent can tell what the tool does at a glance.

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 intended use is implied strongly by the verb 'Builds' and the output-oriented details, but the description never explicitly tells the agent when to prefer this tool over sibling tools such as iban_validate or bic_validate. There is no direct when-to-use or when-not-to-use guidance, so the agent must infer the boundary.

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