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

Annotations declare read-only and idempotent. The description adds that inputs and outputs are percentages, clarifying unit convention. The formula is simple but no additional behavioral details such as rounding or edge cases are disclosed.

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?

Single sentence, front-loaded, and every word earns its place. Efficiently communicates the formula and unit expectations with no waste.

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 two-parameter calculator with full schema coverage, read-only annotations, and an output schema present, the description is adequate. Could mention the inverse relationship to tax-equivalent-yield, but that is not required for basic operation.

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 already documents both parameters with percentages. Description explicitly states 'yield reduced by tax rate,' clarifying the mathematical relationship between yieldPct and taxRatePct beyond field-level descriptions.

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?

Description clearly identifies the tool as computing after-tax yield via tax-rate reduction, distinguishing it from related yield tools. Uses a noun phrase rather than an explicit verb, but the purpose is unambiguous.

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 when-to-use guidance, no mention of alternatives like tax-equivalent-yield, and no context for when this calculation applies. Merely states what it does without exclusions or prerequisite context.

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