calculate_percentage

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

Annotations already fully cover the safety profile (readOnlyHint, destructiveHint, idempotentHint). The description adds 'Read-only and deterministic' which is redundant but confirms behavior. No additional behavioral details (e.g., precision, error handling) are provided beyond the annotations.

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 four sentences, each serving a clear purpose: operations overview, inputs, return value, behavioral note. No wasted words. Information is front-loaded and efficiently structured.

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?

The tool is simple (no output schema, few parameters). The description covers what the tool does, inputs, and behavior. It could mention the return type (number) explicitly, but overall it is sufficiently complete for an agent to use correctly.

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 100% with clear descriptions for each parameter and enum values. The description adds minimal value beyond restating that meanings depend on operation. With full schema coverage, 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 it performs three specific percentage operations, naming the operation parameter and summarizing each. It distinguishes itself from sibling tools (all specialized calculators) as the only generic percentage calculator.

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 implicitly guides usage by naming the three operations and their effects. However, it does not explicitly state when to use this tool versus alternatives, or provide exclusion criteria. Since siblings are all domain-specific, the guidance is adequate but not explicit.

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