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

The description accurately indicates the tool performs calculations, consistent with the readOnlyHint annotation. It adds minimal behavioral context beyond the annotation, but there is no contradiction.

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 sentence that conveys the purpose and modes, but it is somewhat lengthy (65 words). It could be more concise or structured (e.g., using bullet points) for easier scanning.

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 calculation tool with three parameters and no output schema, the description adequately explains all modes and parameter roles. No critical information is missing.

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 input schema covers 100% of parameters with descriptions. The tool description restates the modes but does not add additional semantic meaning beyond what the schema already provides. Baseline 3 is appropriate.

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 states the tool performs percentage calculations with five distinct modes, each briefly explained. It effectively distinguishes from sibling tools (other calculators) by specifying its unique functionality.

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 lists five modes and their use cases, providing clear guidance on when to use each. However, it lacks explicit instructions on when not to use this tool or comparisons to alternatives, which would make it more comprehensive.

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