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

No annotations exist, so the description carries the full burden. It usefully discloses that interest is computed per half-year period and that each figure is returned with its legal reference, but it omits jurisdiction coverage, behavior for unsupported countries, and the EUR-only constraint implied by the schema — meaningful gaps for a 24-parameter legal calculation.

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?

Two sentences, zero filler, with the core outputs front-loaded ahead of the secondary detail about legal references.

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 with 24 parameters, no annotations, and no output schema, the description explains only the calculation's purpose. It does not group or explain the large optional identity/banking field set, list supported jurisdictions, or describe the response shape beyond "each number comes with its legal reference."

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 only 38% across 24 parameters, so the description must compensate and does not. It never mentions the four required inputs, the eurPlnRate Polish-law special case, the dueDate-null fallback, or what the many optional debtor/creditor/banking fields are for.

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?

Nails a specific verb ("Calculate") and three concrete outputs — statutory late-payment interest, fixed recovery-cost compensation, and the total — scoped to an unpaid EU B2B invoice. That is enough to separate it from siblings like draft_reminder or get_status, but the description never names those siblings or states the boundary explicitly.

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?

"for an unpaid EU B2B invoice" implies the applicable scenario, but there is no explicit when-to-use/when-not, no statement that this is a pure computation vs. the drafting/status siblings, and no guidance on which jurisdiction to pass when creditor and debtor differ.

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