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

Annotations already cover read-only and idempotent behavior, so the description benefits from a lower bar. It adds meaningful behavioral context beyond annotations: the call is 'signed,' it produces an 'audit-ready compliance report' and a 'signed XDR-1 receipt,' and it is intended as a pre-payment fraud defense. No contradiction with annotations.

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 compact and front-loaded: the core function appears first, followed by a cost-benefit statement and the compliance outputs. Every sentence contributes a distinct piece of information, with no filler or tautology.

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 an output schema present and annotations covering read-only/idempotent safety, the description does not need to explain return values. It covers the main scenarios, outputs, and value proposition. The only minor gap is clarity around optional-parameter combinations, which is partially mitigated by the schema marking all parameters optional.

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%, and the input schema already documents each parameter as an optional vendor identifier. The description restates the parameter set (IBAN, LEI, VAT, company number) but adds no semantic detail beyond the schema, such as whether at least one identifier is required or how combinations affect the result. Baseline 3 is appropriate.

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 states a specific verb ('screens'), a clear resource (vendor IBAN + LEI + VAT + UK company number), and the combined one-call nature that distinguishes it from sibling individual-check tools. It also communicates the output artifacts (compliance report, XDR-1 receipt), making the tool's role unmistakable.

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 clearly implies when this tool is preferred: when multiple vendor identifiers need screening in one call, especially 'before funds move.' It positions the tool against the alternative ('Saves 50% vs individual checks'), though it does not explicitly name the sibling tools or state when NOT to use it, such as when only a single identifier check is needed.

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