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

Annotations already declare a safe, read-only, closed-world calculation. The description adds substantive behavioral context beyond that: combined TDS across both properties, subject-property GDS, a 20% minimum down payment unless occupying, and optional rental income add-back. It still does not explain the returned breakdown or lender assumptions.

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?

It is one front-loaded sentence with no filler, and the colon list efficiently summarizes the calculation. It is dense and jargon-heavy, but appropriately sized for a compact tool description.

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 19-parameter calculator with no output schema, the description supplies the headline output and main qualification mechanics. It omits return-value structure, assumptions or caveats, and how province and intent materially affect results, so it is adequate but not complete.

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 schema already documents all 19 parameters in detail. The description adds high-level relationships such as combined TDS, the down-payment rule, and rental add-back, but little parameter-specific meaning beyond what the schema provides.

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 states a specific computed output—maximum purchase price for a second property while retaining the current home—and distinguishes the scenario from primary-home affordability via combined TDS across both properties. Cottage, rental, and second-home cases are explicitly named.

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?

It gives clear usage context: a second property while keeping the current home, with vacation/rental/personal-home intent cases named. It does not explicitly route the agent to or away from sibling tools such as mortgage_affordability or mortgage_qualifier, and it states no exclusions or limitations.

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