Calculate max affordable home price

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

Annotations already establish readOnly, idempotent, and closed-world behavior, so the bar is lower; the description still adds real value by declaring 'No network — pure local math' and by spelling out the return contents (max price, binding constraint, full PITI breakdown). With no output schema, that return-shape disclosure is genuinely useful. It stops short of 5 because it says nothing about error cases or edge behavior (e.g., zero down payment).

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 tight sentences: the core purpose first, then inputs, then outputs, with the local-math note last. Every sentence carries information an agent needs and none is redundant.

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 10-parameter, no-output-schema tool, the description covers purpose, most inputs, return contents, and the stateless/no-network characteristic. The one real gap is that it does not explain the overridable DTI caps or defaults for the optional cost parameters, which matters for a tool whose whole premise is a debt-ratio rule.

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 60%, so the schema already documents the DTI caps, interest rate format, loan term, and property-tax rate. The description recasts the inputs in plain language ('monthly income, recurring monthly debts (car loans, student loans, etc.), down payment, interest rate, and optional property-tax rate / insurance / HOA / loan term') and clarifies which are optional, which is a modest addition over the schema. It never mentions the tunable front_end_dti/back_end_dti parameters beyond the fixed '28/36' framing, leaving part of the 60%-uncovered surface unaddressed.

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 a specific verb and outcome: solving for the maximum affordable home price under the 28/36 DTI rule, which is inherently distinct from a payment-calculator sibling like zillow_calculate_mortgage. It is clear and concrete, but it never names or contrasts an alternative tool, so it stops short of the sibling differentiation a 5 requires.

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?

Usage is implied by the framing ('Solve for the maximum home price you can afford'), which tells an agent this is for affordability/budget questions rather than payment math. There is no explicit when-to-use, no when-not-to-use, and no reference to zillow_calculate_mortgage or zillow_estimate_rent_vs_buy, so routing must be inferred.

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