vat_mod97_checkStructural VAT check (BE mod-97 family).
| Name | Required | Description | Default |
|---|---|---|---|
| vat_number | Yes | EU VAT id; BE mod-97 checksum (BE prefix optional). |
| Name | Required | Description | Default |
|---|---|---|---|
| tool | No | ||
| scope | No | ||
| valid | Yes | ||
| reason | Yes | ||
| country | No | ||
| normalized | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already provide readOnlyHint and idempotentHint, so the safety profile is covered. The description adds the useful qualifier 'structural' to indicate this is a checksum-level check, not a registry lookup, which goes slightly beyond the annotations. It does not describe failure behavior, but the output schema likely covers result 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 compact phrase that front-loads the essential concepts: the structural nature of the check and the BE mod-97 family. There is no filler or redundant elaboration.
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, read-only tool with a clear input schema and an output schema, the description is largely sufficient. The main gap is the lack of explicit usage guidance against siblings, but the low complexity and strong annotations keep the definition complete enough for invocation.
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 has 100% description coverage, with vat_number already explained as an EU VAT ID using the BE mod-97 checksum with an optional BE prefix. The tool description adds no further parameter-level information, so the schema-baseline score of 3 is appropriate.
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 checked resource as a VAT number and specifies the exact algorithm family (BE mod-97), so an agent can distinguish it from generic checks like luhn_check or abn_check. It lacks an explicit verb like 'validates' or 'verifies', and 'structural' is not expanded, but the core purpose is unambiguous.
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?
No guidance is given about when to choose this tool over alternatives. The description does not state that it only checks structure/checksum rather than registration status, nor does it mention sibling tools such as gstin_check or luhn_check that might be confused with it.
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 identifier type or specific function (e.g., IBAN vs. EIN vs. block info), with no overlap even among similar validation routines. The batch and rental tools combine distinct sub-checks without ambiguity, making misselection unlikely.
Tool names are uniformly snake_case and mostly follow a descriptive pattern, but the action verbs vary (e.g., 'check', 'format', 'info', 'guard', 'verdict') rather than a single verb_noun structure. While clearly readable, the pattern is not perfectly uniform.
At 28 tools, the server feels like a broad utility pack rather than a focused domain. The count exceeds the 'heavy' threshold and includes three distinct sub-domains (financial identifiers, rental fraud, on-chain queries), making the surface area hard to navigate coherently.
The identifier validation coverage is thorough (most common checksums), rental checks cover risk, deposit, and verdict, and on-chain tools handle balances, activity, and settlement history. Minor gaps exist (e.g., no token transfer history, no generic identifier detection) but agents can likely work around them.