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

With no annotations, the description carries full burden. It discloses the computation itself and a pricing/trial note, which is useful context, but says nothing about error handling (e.g., zero or non-numeric debtService), return format, or the fact that both inputs are optional yet required for the math.

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?

One front-loaded sentence states the operation and formula, followed by a brief promotional note. No filler, though the free-trial tag is not strictly functional.

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 the formula largely implies the output, and no output schema exists to require more. However, nothing explains the result shape, rounding, or the zero-required-parameter oddity, leaving minor gaps for a 2-parameter tool.

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 0%, so the description must compensate. It does name both parameters and assigns their roles in the formula, which is more than the bare schema offers, but it does not clarify that these numeric values arrive as strings or their expected format.

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?

States a specific verb ('Computes') and resource ('debt service coverage') and gives the exact formula (netOperatingIncome / debtService), which distinguishes it from other finance siblings like interest-coverage or debt-to-equity without opening a schema.

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?

There is no when-to-use guidance, no prerequisites, and no named alternative among the many finance-ratio siblings. The agent must infer the use case entirely from the formula.

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