Free IBAN check (ISO 13616 check digits + country length), rate-limited per IP, no API key needed. For volume use the paid HTTP endpoint POST /v1/iban/validate (1 credit) — it has no IP limit.
| Name | Required | Description | Default |
|---|---|---|---|
| iban | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of disclosure. It transparently mentions rate limiting per IP, the free tier, and the lack of an API key requirement, plus the paid endpoint's lack of IP limit. The only missing context is the exact response format, but the described behavior is adequately clear.
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 description is two sentences, front-loaded with the core purpose and immediately followed by the rate-limit/free-info and a clear alternative. Every word earns its place, with no fluff.
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 simple single-parameter validation tool, the description covers the essential context: what it does, free vs. paid, rate limiting, and authentication. It doesn't detail the success/error response, but that is typical for such a tool and not a major gap given the low complexity.
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%, but the tool has only one parameter (iban) whose name and constraints are self-explanatory. The description does not elaborate on the parameter format beyond the tool's purpose, but the ISO 13616 mention implies the expected input. This is adequate but not enhanced.
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 clearly states that the tool performs a free IBAN check using ISO 13616 validation, including check digits and country length. It distinguishes this tool from sibling tools by specifying its unique domain (IBAN validation) and mentions the paid alternative, making its purpose unmistakable.
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?
It explicitly provides usage context: free for low-volume use, rate-limited per IP, no API key needed, and directs users to the paid HTTP endpoint for volume use. This gives clear guidance on when to use this tool versus the alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct resource: FX rates, holidays, timezones, VAT rates, and IBAN validation. There is no functional overlap, so an agent can easily select the right tool for a task.
All tool names follow a consistent <verb>_<noun> snake_case pattern: get_fx_rate, get_holidays, get_timezone, get_vat_rate, validate_iban. The verb varies but the style is uniform and predictable.
Five tools is an appropriate scope for a utility server focused on EU-related data. Each tool provides a clear, non-redundant capability, and the count is neither too sparse nor overwhelming.
The set covers the key EU administrative and financial data points (FX, holidays, timezone, VAT, IBAN). A minor gap is the lack of a country metadata tool, but the existing tools cover core workflows without dead ends.