calculate_annuity_payment

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It states it calculates periodic payments and returns specified values, but omits critical details such as compounding frequency (assumed monthly?), payment timing (beginning or end of period), rounding behavior, or handling of edge cases (e.g., zero interest rate). The description adds minimal behavioral context beyond the obvious 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?

The description is extremely concise at two sentences. The first sentence front-loads the core purpose (calculate periodic payment). The second efficiently provides return field names and a pointer to related tools via list_bundles. No unnecessary words, and every sentence serves a clear purpose.

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?

Given the tool's simplicity (3 required parameters, no enums, output schema exists), the description covers the basics: what it calculates and what it returns. It also references list_bundles for further context. However, it lacks examples, does not explain the underlying formula (e.g., standard annuity, compounding assumptions), and does not address potential pitfalls (e.g., interest rate in percent vs decimal). For a financial calculator, more completeness would be beneficial.

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%, with each parameter clearly described (principal amount EUR, annual interest rate percent, number of payment periods in months). The description adds the return field names but no additional semantic information about the parameters. Since the schema already provides adequate explanations, the description does not significantly enhance parameter understanding.

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 clearly states the tool calculates periodic payment amounts for loans or annuities. It lists the return fields (monthly_payment_eur, total_paid_eur, total_interest_eur) and references list_bundles for related calculators, which provides some differentiation from similar tools like calculate_loan_payment. However, it could be more explicit about its specific niche among many calculate_ siblings.

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 suggests using list_bundles to find related finance calculators, implying this tool is part of a suite. However, it does not explicitly state when to use this tool versus alternatives (e.g., calculate_loan_payment), nor does it provide usage context like typical loan types or scenarios. This leaves the agent to infer applicability.

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