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

With no annotations, the description carries the burden and adds useful behavioral context: deterministic math, line-by-line quotability, output categories, and the x402 pricing model ($0.01/call USDC on eip155:8453). It does not explicitly state read-only/no-side-effect behavior or computation assumptions, but for a calculation endpoint the key traits are largely covered.

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?

Front-loads the core output summary and follows with usage and pricing. It is appropriately sized, though the phrase "Use this when an agent needs to full yearly schedule" is slightly awkward and could be tightened.

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?

No output schema or annotations exist, so the description must explain return content, which it does by naming the payment, yearly table, total interest, and extra-payment savings. It could be more complete with assumptions (monthly compounding, payment timing) or exact output format, but it is sufficient for an agent to understand and invoke the tool.

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 four parameters. The description adds only high-level meaning by noting that extra monthly payments affect payoff timeline and interest saved; it does not add per-parameter constraints or format details beyond the schema.

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?

States a specific resource and verb ("Full loan amortization") and enumerates the concrete outputs: monthly payment, yearly principal/interest/balance table, total interest, and extra-payment savings. This differentiates it from the simpler sibling calculators_loan_payment_calculator by scope and output depth.

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?

Includes an explicit usage condition: "Use this when an agent needs to full yearly schedule + extra-payment savings." It gives a clear context for selection but does not name alternatives explicitly or state when not to use it, leaving the sibling comparison implicit.

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