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

With no annotations, the description carries the full behavioral burden but only adds the fact that a decimal value is returned. It says nothing about edge cases critical to this operation, such as a zero denominator, negative signs, or improper fractions, nor about error behavior.

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?

A single front-loaded sentence with zero filler. Every clause earns its place by naming the operation and the return value.

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 math utility with no output schema, stating the return value (decimal) is helpful, but the nested, undescribed payload plus missing edge-case behavior leave notable gaps for an agent deciding how to call it.

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 0% and the input is a nested payload object, so the description should compensate but does not. The field names numerator/denominator are largely self-evident, yet nothing clarifies accepted integer form, sign handling, or the wrapping payload structure.

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+resource ('Simplify a fraction to lowest terms') and even notes the secondary output ('return its decimal value'). It is clearly distinguishable from math-adjacent siblings like number_roman or number_radix, though it never explicitly contrasts with any of 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 offers no when-to-use guidance, no alternatives, and no prerequisites. It simply says what the tool is, leaving the agent to infer applicability.

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