calculate_with_prepayment

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

No annotations are provided, so the description must disclose behavioral traits itself. It states that the tool 'Calculate EMI outcomes' and returns 'a Backend JSON payload capturing EMI adjustments, duration changes, and savings or an error structure,' which implies a pure calculation with no side effects. However, it does not explicitly confirm that this is a read-only operation, nor does it describe edge cases, error conditions beyond 'error structure,' or how parameters like prepayment_start_month are validated. This adds some but not rich behavioral transparency.

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 with a concise one-sentence summary, followed by an Args list with one line per parameter, and a Returns section. Every sentence provides useful information with no filler. It is appropriately sized for a 7-parameter tool and front-loaded with the 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 complexity (7 parameters, no annotations, no enums in schema) and an available output schema, the description covers all parameters with their semantics and describes the return structure. Minor gaps remain: it does not specify the exact valid values for prepayment_frequency and calculation_method, nor does it explain how errors are structured beyond 'or an error structure.' This is adequate but not exhaustive.

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 0%, so the description must compensate for all 7 parameters. It does so by explaining each parameter's meaning, for example, 'interestRate: Annual interest rate expressed in percent (e.g. 9.5)' and 'prepayment_start_month: Month number when prepayment begins (1-indexed).' It gives examples for prepayment_frequency and calculation_method, but does not enumerate all allowed values, which limits completeness.

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 'Calculate EMI outcomes when regular prepayments reduce the outstanding principal' clearly states a specific verb (calculate), resource (EMI outcomes), and the special condition (prepayments). This distinguishes it from sibling tools like calculate_emi, calculate_schedule, and compare_loans, which likely don't focus on prepayment adjustments.

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 gives a clear context for when to use the tool: 'when regular prepayments reduce the outstanding principal.' It does not explicitly name alternatives or state when not to use it, but the context is unambiguous enough for an agent to select it for prepayment scenarios.

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