Determine whether a business needs to register for VAT in a given country, given customer type and annual revenue.
| Name | Required | Description | Default |
|---|---|---|---|
| country | Yes | ||
| supply_types | No | Supply mix — `goods`, `digital_services`, `professional_services`, etc. Defaults to `[goods]` when omitted. | |
| customer_type | No | ||
| sale_countries | No | Other countries where the business sells | |
| annual_revenue_eur | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It states what decision is made but not how thresholds are applied, what output format is returned, or which inputs are actually required versus optional. The description also omits any assumptions, limitations, or country-specific handling details.
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 a single focused sentence with no filler, and it front-loads the core purpose. It is efficiently written, though its brevity means it can't carry the behavioral and parameter detail the tool needs.
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?
With no annotations and no output schema, the description leaves too much unstated. It doesn't describe the return result, threshold logic, or how optional parameters like supply_types and sale_countries affect the decision. It also creates ambiguity by naming customer_type and annual_revenue while only country is required in the schema.
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 description coverage is only 40%, so the description must compensate, but it only mentions customer type and annual revenue as inputs and adds no semantic detail such as thresholds or units. It doesn't clarify the required country parameter or the roles of supply_types and sale_countries. The added value over the schema is minimal.
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 identifies the tool's function: it determines whether a business needs to register for VAT in a country, using customer type and annual revenue as key inputs. This is specific enough to distinguish it from related tools like vat_rate_lookup or vat_number_check, though it doesn't explicitly contrast with siblings such as vat_compliance_full.
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 implies the tool should be used when an agent needs a VAT registration eligibility decision with customer type and revenue available. However, it provides no explicit guidance on when not to use it, no alternative tool recommendations, and no indication of how it fits alongside vat_compliance_full or reverse_charge_certificate.
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 has a distinct primary purpose: registration, validation, rate lookup, reverse-charge certification, and full compliance analysis. There is slight overlap because reverse_charge_certificate also validates VAT IDs via VIES, but the descriptions clearly differentiate the outputs and use cases.
Most tools follow a descriptive snake_case pattern with a vat_ prefix, such as vat_number_check and vat_registration_check. reverse_charge_certificate and vat_compliance_full deviate slightly from the prefix/pattern but remain consistently readable.
Five tools is a well-scoped size for a VAT compliance server. Each tool covers a distinct compliance need without unnecessary redundancy or bloat.
The set covers the core VAT compliance workflow: registration eligibility, VAT number validation, rate lookup, reverse-charge eligibility, and a broad gap analysis. Some edge cases like reverse charge for goods or detailed place-of-supply rules are not explicitly covered, but the core domain is well served.
