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

Annotations already establish readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description usefully discloses the calculation methods (30% rule, 40x test, debt inclusion), which is real behavioral context, but it says nothing about output structure or how the methods combine or conflict.

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 tight sentences, with the illustrative example front-loaded before the methodology. The trailing marketing URL is low-value but minor; nothing is padded or 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?

With 4 parameters, no output schema, and no required params, the description does explain the underlying formulas, which is helpful. However, it never indicates what the tool returns (a single rent figure? a range? a breakdown across the three tests), leaving an agent to guess at the response 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 description coverage is 100%, so the schema already documents income, debts, period, and currency. The description only loosely gestures at salary and monthly debts and adds no syntax, bounds, or currency/period interaction detail. Baseline 3 applies when the schema carries the load.

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 the resource (rent affordability) and specifies the exact methodology used (30% rule, landlord 40x test, monthly debts), which is more concrete than most calculator siblings. It stops short of distinguishing itself from adjacent tools like home_affordability_calculator, rent_vs_buy_calculator, or debt_to_income_calculator in the sibling list.

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 tool versus the many affordability/rent siblings, no prerequisites, and no exclusions. The leading example ('A $60,000 salary supports about $1,500 rent') illustrates output but does not guide tool selection.

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