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

The description states 'Expression discarded' but does not disclose any side effects, permissions, or lack thereof. With no annotations and a misleading description, the actual behavior is opaque.

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 very short, but it is not appropriately sized because it omits essential information. The sentences are concise but do not contribute to a useful understanding.

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?

Given the complexity of the schema and the presence of many sibling tools, the description is completely inadequate. It does not explain what the tool actually does, how it handles inputs, or what the output might be.

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 description fails to explain the meaning or role of any of the 9 parameters. The schema descriptions themselves are present but are inconsistent with the stated arithmetic purpose, adding no clarity.

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 claims the tool evaluates arithmetic, but the schema parameters (URLs, paths, timezones, etc.) are entirely unrelated. This is misleading about the tool's actual purpose.

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 guidance is provided on when to use this tool versus the many sibling tools, such as normalize-url or validate-json. The description offers no context or alternatives.

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