Validate an EU VAT number against the official EU VIES service (live government lookup). Returns whether it is registered/valid and, if available, the registered trader name + address. An LLM cannot know this without the real lookup — use this before invoicing/reverse-charging an EU B2B customer. Input e.g. 'DE811569869' or 'IE6388047V' (country code + number).
| Name | Required | Description | Default |
|---|---|---|---|
| vat_number | Yes |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses that the tool performs a live government lookup, returns validity and optional trader details, and implies no side effects. It does not mention rate limits or failure modes, but the core behavior is transparent.
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 concise with no wasted words. It front-loads the main purpose and includes examples and usage context in a few sentences.
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?
Given the moderate complexity and absence of output schema, the description covers the essential aspects: purpose, real-time nature, expected output, and when to use. It does not address potential service unavailability or detailed output structure, but it is sufficient for a validation tool.
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 provides no description for the single parameter 'vat_number' (0% coverage). The description adds value by giving format examples ('DE811569869' or 'IE6388047V' with country code + number), but it does not fully specify allowed country codes or exact length constraints.
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 specifies the action (validate), resource (EU VAT number), and method (official EU VIES live lookup). It includes input format examples and distinguishes from sibling tools like validate_eori and validate_gtin.
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 description explicitly tells when to use it (before invoicing/reverse-charging an EU B2B customer) and explains that an LLM cannot know the data without the lookup. However, it does not mention when not to use it or provide alternatives among siblings.
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 type of validation or calculation (email domain, payout, reorder point, payment split, ABA routing, EORI, EU VAT, GTIN, IBAN, VAT rate). There is no overlap in purpose, and descriptions clarify the specific identifier or operation.
Most tool names use a verb_noun pattern (e.g., validate_aba_routing, check_email_domain), but some are noun phrases (payout_reconciliation, reorder_point, stripe_connect_split, vat_rate_by_country). While clearly descriptive, the verb-prefix inconsistency slightly reduces predictability.
With 10 tools, the server covers a focused set of commerce validation and calculation tasks without being too sparse or overwhelming. Each tool serves a clear, independent purpose.
The tool set covers key commerce validations (email, bank routing, IBAN, VAT, EORI, GTIN) plus useful calculations (payout, reorder, payment split, VAT rates). Minor gaps exist (e.g., phone/address/credit card validation, currency conversion), but the coverage is coherent for the stated domain.