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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds valuable behavioral context beyond that: the tool returns a single tri-state decision, aggregates four sources, has a specific price per call, and explains authentication options (x-credit-token header, free daily tier, no wallet/API key needed). This fully prepares the agent for what happens when the tool is invoked.

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 dense but well organized: the decision question first, then the sources and output, then the use case, then pricing and access details. Every sentence contributes useful information, though the pricing and header details add length that could arguably be trimmed without losing core meaning.

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 tool that aggregates four data sources into a decision, the description covers the inputs, the decision output, the underlying sources, the fraud scenario, and the access/pricing model. The output schema exists to handle return details. The only minor gap is clarifying whether at least one of name, email, or domain is required, but the descriptions and context make that reasonably inferable.

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 100%, so the input parameters are already well documented. The description adds a little context, such as name enabling OFAC and LEI checks and email's domain being used when domain is omitted, but it mostly relies on the schema. This meets the baseline for a fully documented 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 opens with a direct question that frames the decision, then states the tool's job: one call combining four public sources into a GO / HOLD / STOP verdict. It names the exact resources (RDAP, DNS, OFAC, LEI) and the output format, making the purpose unmistakable and distinct from simpler sibling tools like domain_check or sanctions.

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?

The description gives a clear trigger context: trusting an invoice, onboarding a new vendor, or processing a payment-detail change, and explains the fraud pattern it catches. It does not explicitly name alternatives or say when not to use it, but the use case is specific enough that an agent can decide when to invoke it.

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