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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds a useful behavioral hint — output includes 'common lender bands' — but says nothing about whether the result is a number, a band label, or a breakdown, which matters since no output schema exists.

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?

A single terse fragment with no wasted words, but it is under-specified rather than crisp — there is no verb and no front-loaded statement of what the caller gets back. Efficient but too thin for a three-parameter calculator.

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 should describe the return, and it only hints at 'lender bands' without describing the ratios themselves or their interpretation. Adequate for a simple calculator, but gaps remain for an agent needing to act on the result.

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 67%, with monthly_gross_income left undocumented. The description's front-end/back-end framing implicitly maps monthly_housing to the front-end ratio and other_monthly_debts to the back-end, adding mild interpretive value, but it never explains the missing parameter or input units.

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 clearly names the resource — front-end (housing) and back-end debt-to-income ratios — and even scopes the calculation split. An agent can tell this is a DTI calculator, though it never names siblings like rent_to_income or rent_affordability to disambiguate the family of ratio tools.

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?

No statement of when to use this versus the many sibling calculators (rent_to_income, rent_affordability, monthly_income_from_pay). The agent is left to infer that this is the tool to pick when both housing and other debts matter.

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