calculate_loan_payment

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

With no annotations, the description must fully disclose behavioral traits. It lists the return object but fails to mention that the tool is read-only (no side effects), any assumptions (e.g., fixed-rate amortization), or potential edge cases (e.g., zero interest).

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 two sentences, front-loading purpose and output, followed by a pointer to related tools. Every word adds value; no redundancy or padding.

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 presence of an output schema (context signal), the description's mention of return fields is adequate. For a simple, three-parameter loan calculator, the description covers the essentials. A minor gap is not explaining that the calculation assumes equal monthly payments with compound interest, but overall it is sufficiently complete.

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 input schema already describes all three parameters (principal, annual_rate, months) with 100% coverage. The description adds no additional meaning beyond the schema's descriptions, so it meets the baseline of 3.

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 verb (Calculate), the resource (monthly loan payment), and the scope (any generic loan). It also lists the returned fields, distinguishing it from the many sibling tools that calculate other financial metrics.

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 mentions 'any generic loan' implying broad applicability, and references list_bundles for related calculators. However, it does not explicitly state when to use this tool over other loan-related siblings or provide exclusions.

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