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

Annotations already declare this a read-only, idempotent, non-destructive, open-world lookup, so the safety profile is covered. The description adds genuine behavioral detail beyond that: it discloses that 'a company that doesn't report is said so' and that Silver 'can't be judged from the report', which tells the agent how missing or non-evaluable cases surface. It stops short of describing the overall return shape.

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?

It is front-loaded with the core purpose, but the opening is a sentence fragment ('A company's statutory payment reports against...') rather than a clear verb phrase, and the tier/test parentheticals make the middle dense. The information earns its place, but the phrasing could be tightened.

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 burden of explaining what comes back, and it only partially does so by noting non-reporting is flagged and that Silver is unjudgeable. It never describes the actual return structure or fields, which is a real gap for a tool whose output is not otherwise documented.

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?

There is a single required parameter with 100% schema description coverage ('A company number or name'), so the schema already carries the parameter semantics. The description adds nothing about the company argument itself, making the baseline 3 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 makes specific what the tool evaluates: a company's statutory payment reports read against PPN 018's two tests and the Fair Payment Code tier thresholds. It names the concrete evaluation criteria (95% within 60 days, 90% with action plan, 45-day average) so the resource and the operation are both clear. It does not differentiate itself from overlapping siblings like payment_practices or late_payment, which keeps it from a 5.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no mention of alternatives. Siblings such as late_payment, payment_practices, and will_they_pay clearly overlap in domain, yet the description never routes the agent between them. Usage is only implied by the topic.

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