Compare federal student loan repayment plans

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

With no annotations provided, the description carries the full burden, and it does so by explaining that it compares only eligible plans, returns excluded plans with the rule that excludes them, and is computed by a parity-verified engine rather than estimated. It does not describe the exact output shape, but the behavioral detail is substantial.

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 front-loaded with the action, the list of plans, and the outputs, followed by reliability and usage guidance. Every sentence contributes necessary context, and there is no redundant filler or vague marketing language.

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?

The tool has seven parameters and no output schema or annotations, so the description must explain what comes back; it does, listing monthly payment, lifetime cost, excluded plans, and the eligibility rule. Minor details such as exact output formatting or underlying assumed loan terms are absent, but they are not essential for correct invocation.

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%, so the schema already documents all seven parameters. The description reinforces that loanType drives eligibility with a Parent PLUS and consolidation example, but that example already appears in the schema's loanType description, so it adds no new parameter meaning.

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 states a specific verb ('Compares') and resource ('US federal student loan across every repayment plan'), enumerates the eligible plans, and specifies what is returned. It does not explicitly differentiate from sibling tools by name, but its scope is unambiguous.

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 clear usage context: 'Use this instead of calculating federal repayment math yourself' and explains why eligibility is easy to get wrong. It does not mention sibling alternatives or say when not to use the tool, so it stops short of full when/when-not guidance.

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