company_brief

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

With no annotations at all, the description carries the full behavioral burden and does so unusually well: it discloses return structure (key_facts as plain sentences, every section in full, plus a checks map reporting ran/skipped/failed), billing ($0.03 USDC per call), the no-charge-on-empty-result rule, and p99 latency of 15s. Those are exactly the non-obvious traits an agent needs to decide whether to call and how to interpret partial results.

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 first clause identifies the tool and its one-call value immediately, and the source enumeration, audience, routing rationale, and cost/latency tail each carry information. It is dense and a bit long, but no sentence is filler; only the six-source list borders on over-enumeration given sections are described later.

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 exists, so the description must explain returns — and it does, describing key_facts, full sections, and the checks map. All six optional parameters are covered, the entry requirement is stated, and pricing/latency plus partial-failure semantics round out everything needed to call and interpret results.

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 100%, so per-parameter meaning is already handled, but the description still adds cross-parameter guidance the schema cannot express: at least one identifier is required, name+domain produces the fullest brief, and the VIES caveat about countries like DE returning no name explains why name should be sent alongside vat_number. That is genuine semantic value beyond the schema.

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 names a specific verb+resource (company check/KYB plus enrichment) and enumerates exactly what the brief contains — LEI legal entity data, VIES VAT, OFAC/EU/UN sanctions, RDAP/MX/SPF/DMARC, tech stack, news. It explicitly positions itself against six named siblings (company-lookup, vat-validate, sanctions-screen, domain-check, tech-stack, news-search), so an agent can tell what it aggregates without opening any schema.

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?

It gives concrete use cases (supplier/customer onboarding, lead qualification, due diligence, sales research, European companies) and states the entry condition — at least one of name, vat_number, lei or domain, with name+domain giving the fullest brief. The cost-based routing note against single-purpose siblings is a clear alternative signal. It does not, however, distinguish itself from the closely related kyb_check and company_enrich siblings, which is the remaining gap.

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