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

Annotations already declare this as a safe read-only, idempotent operation, but the description adds substantial behavioral context: it lists the returned metrics, discloses the assumption of constant income and on-time payments, and notes which plans count for PSLF. Those are meaningful execution details beyond the structured annotations.

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 comparison and remains compact for a five-parameter financial tool. The long parenthetical listing the Tiered Standard income thresholds is informative but dense and could be structured more cleanly.

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, lack of an output schema, and safe read-only annotations, the description is complete enough to call correctly. It names the compared plans, conditions, returned values, key assumptions, and PSLF treatment.

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 each parameter thoroughly. The description reinforces the conditional role of the loan-date parameter and the constant-income assumption for AGI, but it does not add syntax or interpretation beyond what the schema provides.

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 uses a specific verb ('Compares') and names the exact plans being compared: RAP, Tiered Standard, and conditionally the 10-year Standard plan. This is far more specific than the sibling calculate_rap_payment tool and makes the tool's scope immediately clear.

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 establishes the comparison context and states the condition under which the 10-year Standard plan is included. It does not explicitly direct the agent away from calculate_rap_payment or explain when a single-plan calculation would be preferable, so it stops short of full alternative routing.

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