mortgage_calculator

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

No annotations are provided, so the description must carry the full behavioral disclosure burden. It adds the cost requirement ($0.001 USDC via x402) but says nothing about the operation's behavior: what inputs it accepts, whether it triggers payment, what it returns, or whether it is read-only. This is a significant gap for a payment-gated tool.

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 text is very short, but 'mortgage calculator' repeats the tool name and adds no value. The cost sentence is the only substantive part, so half the description is redundant. The structure is front-loaded, but under-specification outweighs brevity.

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 financial calculator with a generic schema and no output schema, this description is severely incomplete. It lacks any explanation of expected parameters, return values, or payment flow. The agent has no way to know how to correctly invoke the tool or interpret results.

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 only has a generic 'params' object with no named properties, and the description adds no meaning. An agent cannot infer that principal, interest rate, and term are likely needed, nor any defaults or units. The schema coverage statistic is 100%, but that refers only to the generic wrapper, not actual parameter semantics.

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 labels the tool as a 'mortgage calculator — Finance & Math tool' but never states what it does (e.g., 'calculate monthly mortgage payments'). It restates the tool name and gives a broad category, and without a verb it fails to distinguish from sibling tools like loan_calculator or amortization_calc.

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?

There is no guidance on when to use this tool versus alternatives. The cost note ('Costs $0.001 USDC via x402') is a pricing detail, not a usage guideline. No prerequisites, exclusions, or alternative tool references are provided.

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