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

With no annotations provided, the description carries the full burden and delivers: paid cost ($0.05), free refusal conditions, mechanism-only series refusal, jurisdiction limitations, legal disclaimer, and receipt semantics. This is unusually thorough for behavioral disclosure.

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?

Packed with necessary operational detail—pricing, formulas, edge cases, auth, receipts—and logically ordered. It is long but every sentence earns its place; minor tightening of the receipt paragraph could improve readability.

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?

Covers pricing, authentication, refusals, receipts, and legal caveats comprehensively. With no output schema, it doesn't explicitly describe the success response shape, though the formula makes the primary output predictable. It also assumes familiarity with 'series' from sibling tools, which is acceptable given the tool ecosystem.

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 100%, but the description adds substantial meaning beyond it: the actual/365 day-count convention, inclusive/exclusive date semantics, the relation between days and from/to, api_key usage bypassing x402, and receipt behavior including the Ed25519 answer receipt. This goes well beyond the parameter descriptions in 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: 'compute statutory interest' on a principal at a statutory-interest series rate, with the exact formula (principal × (rate/100) × (days/365)). The subject matter clearly distinguishes it from sibling compute_* tools like compute_vat and compute_income_tax, and the receipt disambiguation prevents confusion with certified extracts.

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?

Gives explicit usage instructions: choose days or from/to, notes that conflicting both is refused free, and explains the api_key vs x402 payment paths. It doesn't explicitly state when to prefer this over sibling compute tools, but the domain is self-evident and the constraints are clearly laid out.

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