client_from_vat

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does reasonably well: it discloses the external dependency (VIES EU registry), that the default is a non-mutating preparation step, and that create=true performs the write. It omits what happens when VIES lookup fails or returns partial data, and says nothing about permissions or duplicate-client handling.

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?

Three compact sentences, front-loaded with the core action, then the SDI caveat, then the create flag. No filler. The density is high but every clause carries information an agent 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?

No output schema and no annotations, yet the description tells the agent what data comes back (business name, address, verified city/province) and what the create flag does, which is the essential shape for a 7-parameter enrichment tool. Gaps remain around failure modes and the role of company_id and email, which are undocumented in both schema and description.

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 57%, so the description needs to compensate and largely does: it explains vat_number (with or without country prefix is covered by schema), create, ei_code and certified_email, and adds genuine domain meaning by noting the SDI code is not publicly available and PEC is the fallback. It adds nothing for email, country, or company_id.

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?

States a specific verb and resource: builds a client's master data (anagrafica) from a VAT number via VIES, returning business name, address, and verified city/province. That is far more than the bare name. It does not explicitly contrast itself with the sibling create_client, so an agent must infer that this is the VIES-enriched path versus manual entry.

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?

Gives clear operating context: use it when you have a partita IVA and want registry data resolved, and it explains the preview-versus-write split ('Con create=true crea il cliente'). It also advises what to do when the SDI code is unavailable (ask the client or use their PEC). It stops short of naming alternatives or stating when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.