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

With no annotations, the description carries the full behavioral burden. It does disclose useful behavioral context by naming the 30% rule and DTI ratio, and it suggests the output is a comfortable rent range. However, it does not state assumptions such as gross vs. net income or how the two rules are combined.

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 a single, tight sentence with no filler. It front-loads the primary question and concisely lists key method components, though it could be slightly more explicit about the action it performs.

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 simple calculator with two parameters and no output schema, the description is nearly adequate but still leaves gaps. It mentions the output concept ('comfortable rent range') but omits usage context and exact calculation behavior, which an agent would need to invoke it confidently.

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 description coverage is 100%, so the baseline is 3. The description adds some interpretive value by implying monthlyIncome drives the 30% rule and monthlyDebts drives the DTI ratio, but it does not provide additional formatting, required input details, or edge-case semantics.

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 conveys the tool's purpose through the question 'How much rent can you afford?' and identifies its method ('30% rule, DTI ratio, comfortable rent range'). This distinguishes it from sibling tools like mortgage or ROI calculators, though it lacks an explicit verb like 'calculate'.

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 guidance is given about when to use this tool versus alternatives such as calculate_mortgage or calculate_rental_roi. There are no conditions, exclusions, or context hints beyond the general purpose.

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