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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior. The description adds meaningful behavioral detail beyond that: it rounds up to whole dollars and never down so the target is always met, and it returns rents for 0.75, 1.00 and 1.25 in addition to the target rent.

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 front-loaded and appropriately short, stating the main result first and then the additional DSCR outputs. It has minor redundancy in saying both 'rounded up to whole dollars' and 'Rounds up, never down', but the repetition reinforces an important behavior.

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 12-parameter calculation tool with no output schema, the description adequately explains what is computed, the default target, rounding behavior, and alternate DSCR outputs. The exact output structure is not spelled out, but the essential return semantics are clear enough for an agent to call it correctly.

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 all 12 parameters are already well documented in the schema. The description mentions the major input categories and the default target DSCR, but adds no syntax, format, or interpretation details 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 uses a specific verb and resource: it 'solves for the smallest monthly rent' that reaches a target DSCR, with scope defined by loan, rate, term, tax, insurance, HOA and vacancy. This clearly distinguishes it from siblings such as calculate_dscr and max_loan_for_target_dscr without needing to name them.

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 description implies when to use the tool by stating it solves for required rent against a target DSCR and defaults target_dscr to 1.25. However, it does not explicitly say when to choose this versus calculate_dscr or max_loan_for_target_dscr, leaving alternatives to inference.

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