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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds genuine behavioral context beyond that: the tool returns a 0-1 confidence score, cites evidence sources (Wikidata, homepage brand match), and surfaces alternatives, rejected look-alikes and social links. It does not say how minConfidence affects the response or what happens on no match, keeping 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?

A single sentence with the core purpose front-loaded and zero filler. The trailing list of outputs is dense but earns its place since there is no output schema; the one sprawling sentence is the only structural weakness.

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 output schema, the description carries the return-value burden and does it well, naming confidence, evidence, alternatives, rejected look-alikes and social links. Missing details are around the minConfidence threshold's effect on results and failure/ambiguity behavior, which are secondary for a read-only lookup.

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 67%, with the company parameter well documented in the schema. The description adds the meaning of the confidence output (0-1) and implies the verification use of the input, but never explains the country code or the minConfidence default of 0.6 and its filtering behavior. Marginal value over 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?

States a specific verb and resource ('Find the official website domain of one company from its name') and scopes it to a single company, so the agent knows exactly what it resolves. It also enumerates the shape of the answer, which reinforces the purpose. No siblings exist, so differentiation is moot.

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?

Usage is implied by the lookup framing, but there is no explicit statement of when to reach for this tool, what prerequisites exist (e.g. ambiguity handling, rate limits), or when the result should not be trusted. With no siblings the alternative-routing burden is low, but the guidance remains implicit rather than stated.

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