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

Annotations already declare this as a non-destructive, closed-world read, so the bar is lower. The description still adds real domain behavior beyond them: the 39%/44% limit thresholds, the 50% condo-fee treatment, and that a qualifying view should use the stress-test-rate 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?

Two tightly packed sentences with the core computation front-loaded and the two domain rules (condo haircut, stress-test rate) following. No filler or restated title.

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 7 parameters and no output schema, the description should say more about what comes back (both ratios, per-ratio pass/fail against the 39%/44% limits) and whether defaults like heating/property tax are applied. The 'against the limits' phrasing hints at a comparison but does not specify the return shape.

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 100%, so the baseline is 3. The description goes slightly beyond the schema by explaining the condo-fee 50% haircut in context and by advising that mortgagePayment should reflect the stress-test rate for qualifying purposes, which changes what value the agent should supply.

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 computation (GDS and TDS ratios) from specific inputs (income, housing costs, other debts) benchmarked to the 39%/44% thresholds. It is distinguishable from nearby tools like debt_to_income or mortgage_qualifier by naming the exact ratio pair, though it never names those siblings explicitly.

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 line about using the stress-test-rate payment gives one piece of situational guidance, but there is no explicit when-to-use versus alternatives (e.g. debt_to_income for TDS-only, mortgage_stress_test for rate qualification). Usage is implied rather than routed.

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