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

With no annotations, the description carries the behavioral burden and does well: it discloses that the call aggregates two sources, that results are labelled with confidence and source, and that a crawl bounded by max_pages occurs. It omits cost/latency implications and any auth or rate-limit notes, which keeps it short of a 5.

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 tight sentences: output summary first, routing guidance second, parameter semantics third. Every clause carries information and nothing is repeated from the schema.

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 3-parameter aggregation tool with no output schema and no annotations, the description supplies the return shape (registry record + sourced, confidence-labelled contacts), the selection rule versus siblings, and all parameter semantics. Nothing an agent needs to invoke it correctly is missing.

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 0%, so the description must compensate, and it does for all three parameters: cui is identified as the tax code, website is described as overriding the registered one (a semantic not visible in the schema), and max_pages is described as bounding the crawl. Each parameter gains meaning beyond its bare type and default.

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 operation (whole-firm profile in one call) and enumerates exactly what it returns: the ONRC registry record plus contacts from the firm's website, each with confidence and source. It explicitly distinguishes itself from the sibling pair lookup_business + extract_contacts, so an agent can route without opening either 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 states the exact condition for choosing this tool: use it over lookup_business followed by extract_contacts when you want everything about one company. That is an explicit alternative and trigger, not an implied one.

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