Validate an IBAN with the exact mod-97 checksum and country format rules. Returns validity, country, and bank code. Never guess IBAN validity: use this tool.
| Name | Required | Description | Default |
|---|---|---|---|
| iban | Yes | The IBAN to validate |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description bears the full burden of disclosing behavior. It explains the validation method, states the returned values, and signals authoritative deterministic behavior. This is sufficient for a simple validation tool, though edge-case behavior is not discussed.
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?
Every sentence earns its place: the method, the return fields, and the usage directive are each stated in a single focused phrase. There is no filler, tautology, or irrelevant context.
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 tool with no output schema and no annotations, the description provides the essential contract: what is validated, what results are returned, and when to use it. Error-handling details are not covered, but they are not critical for this straightforward validator.
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?
The schema already provides 100% coverage: the only parameter, iban, is described as 'The IBAN to validate.' The description adds no new parameter-level detail, but none is necessary for this self-explanatory single parameter.
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 uses a specific verb ('Validate') and resource ('IBAN'), and adds precision with 'exact mod-97 checksum and country format rules.' It also names the return fields (validity, country, bank code), distinguishing it clearly from sibling tools like generate_test_iban.
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 sentence 'Never guess IBAN validity: use this tool' clearly instructs when the agent should call this tool: whenever IBAN validity needs to be established rather than assumed. It does not explicitly discuss alternatives or exclusions, but the directive is unambiguous.
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.
Most tools have clearly distinct purposes, but some pairs could be confused: html_to_pdf vs url_to_pdf both produce PDFs, read_page vs url_screenshot both fetch a URL, and generate_test_bsn vs generate_brp_test_data both generate Dutch test data. Detailed descriptions mitigate most ambiguity, so agents can usually select correctly.
All tool names follow a consistent snake_case convention with predictable verb_noun patterns (e.g., generate_*, validate_*, memory_*, url_*). The naming is uniform and makes each tool's function easily inferable from its name.
35 tools is a heavy surface for any MCP server, even a general-purpose toolbox. The large number of niche Dutch-specific tools (BRP, UPA, BSN, holidays) may overwhelm agents and increase selection complexity. The server could benefit from splitting into smaller, focused servers.
The server covers a wide range of utilities, but there are notable gaps: no hash generation, no json_to_csv counterpart, and the workflow sub-domain only offers list/run without create/delete. Core utilities are present, but some obvious counterparts and lifecycle operations are missing.