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

The annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is clear. The description adds the computational behavior (division), but does not disclose edge-case handling such as division by zero when annualDebtService is zero.

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, compact sentence that defines the ratio and the calculation. Every word contributes meaning, with no redundancy or unnecessary detail.

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, deterministic financial calculation, the description fully conveys the purpose and computation. The presence of an output schema covers return values, and the two parameters are clearly defined, so no additional context is necessary.

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?

The schema descriptions fully cover both parameters, providing baseline clarity. The tool description adds value by specifying the relationship between the parameters (NOI divided by annual debt service), making the numerator/denominator roles explicit beyond the individual parameter descriptions.

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 defines the tool as the debt service coverage ratio and explicitly states the formula (net operating income divided by annual debt service). This distinguishes it from sibling tools like 'noi' and 'cap-rate' by specifying the exact computation and inputs.

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 provides no guidance on when to use this tool versus alternatives. There is no mention of typical use cases (e.g., evaluating loan risk) or exclusions, leaving the agent to infer context from the formula alone.

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