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

Beyond the readOnlyHint annotation, it clarifies the DTI-relevant vs living-cost distinction, explains that monthly_expenses is used only for the leftover-life check, and describes how address affects property tax and insurance estimates. This adds real behavioral context beyond the 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 core question and output list, then organizes parameter semantics and optional inputs into short, purposeful sentences. No sentence is superfluous.

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?

With no output schema, the description enumerates return values and key calculation inputs clearly, including the verdict scale. It is mostly complete for invocation, though some edge behavior (e.g., what happens when address and rate parameters are both omitted) is left implicit.

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?

It thoroughly explains monthly_debts and monthly_expenses and addresses the optional address and liquid_savings behavior. However, schema description coverage is 0% across 12 parameters, and several parameters such as marginal_tax_rate, fixed_rate, insurance_rate, and property_tax_rate are left to be inferred from their names/defaults.

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 opens with a targeted question and lists a concrete set of outputs (monthly PITI, front/back DTI, income needed, after-tax leftover, cash cushion, verdict). It is specific about the resource and calculation, though it does not explicitly distinguish itself from the sibling affordable_price.

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 first sentence frames the use case as determining whether a buyer can afford a home, and the description gives conditional parameter guidance ('Pass address to ground property tax + insurance... Pass liquid_savings to get the post-closing cash cushion'). It does not name alternatives or exclusions, so it stops short of a 5.

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