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

With no annotations, the description carries the full behavioral disclosure burden and does it well: it states that ineligible plans are listed with reasons, that Parent PLUS runs the consolidation path unprompted, and that loanType affects eligibility, not just rates. These are non-obvious behaviors beyond the input schema.

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?

Three dense sentences with no filler: the first front-loads the purpose and outputs, the second explains the ineligible-plan behavior, and the third highlights the critical parameter. Every sentence earns its place.

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?

For a complex 7-parameter tool with no output schema and no annotations, the description is nearly complete: it specifies the returned comparison dimensions, explains handling of ineligible plans, flags special Parent PLUS behavior, and warns about the loanType dependency. This is enough to invoke the tool correctly without external documentation.

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 coverage is 100%, so the baseline is 3. The description adds meaningful semantic guidance for loanType by emphasizing that it drives plan eligibility and should be chosen accurately, which goes beyond the schema's enum list and helps the agent avoid a critical parameter mistake.

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 names the action ('Compare') and the exact resource ('every federal repayment plan a loan can elect') and enumerates the output dimensions: monthly payment, lifetime cost, forgiveness timing, and estimated tax on forgiven balances. It also names the specific plans, making the tool's scope clear and distinguishable from siblings like estimate_rap_monthly_payment.

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 clearly implies a comprehensive comparison use case and explicitly calls out when Parent PLUS triggers the consolidation path. However, it does not explicitly name sibling tools or state when to use them instead, such as when the user only needs a repayment estimate or a married filing status comparison.

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