loan_amortization

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

With no annotations, the description provides useful behavioral details: the exact payment formula, the conversion of annual_rate to monthly, the effect of extra_payment ('shortens the term'), and the conditional return of the schedule via include_schedule. It does not cover edge cases or rounding, but the core calculation behavior is transparent.

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 well-structured: a one-line summary, the formula (useful for transparency), and a clean Args list. Every sentence adds value, and there is no fluff or redundancy. The front-loaded summary gives immediate clarity.

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 six parameters, no annotations, and 0% schema coverage, the description covers the calculation logic and parameter semantics well. An output schema exists, so return values need not be described. However, it omits explicit usage exclusions and error-handling behavior, leaving a minor gap.

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?

The schema has 0% description coverage, so the description fully compensates by explaining all six parameters: principal (>0), annual_rate (decimal, with example), term_months (>0), extra_payment (optional, shortens term), currency (ISO formatting), and include_schedule (conditional schedule return). This is highly valuable beyond the raw 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?

The description opens with 'Level-payment loan: monthly payment, total interest, payoff, and schedule,' which clearly specifies the tool's function and outputs. The verb is implicit but unambiguous, and the resource (loan amortization) is distinct from sibling tools like compound_growth and depreciation.

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 implies usage for level-payment, fixed-rate loans through the formula and parameter details, but it does not explicitly state when to use this tool versus alternatives (e.g., compound_growth, NPV). No exclusions or alternative tool names are mentioned, so guidance is only implied.

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