calculate_cost_per_use

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

No annotations are provided, so the description must disclose behavioral traits. It states inputs and outputs (cost per use and break-even use count) but does not explicitly confirm it is a read-only operation or mention any side effects, permissions, or rate limits. For a calculator, this is minimally adequate.

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 three sentences, front-loaded with the purpose, then usage context, then inputs/outputs reference. Every sentence contributes, no fluff.

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 tool's simplicity (2 params, output schema exists), the description covers purpose, when to use, inputs, and outputs. It also points to list_bundles for related tools, making it fully adequate for agent decision-making.

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 provides clear descriptions (e.g., 'Item purchase price' and 'Expected number of uses') with 100% coverage. The description adds value by mentioning 'expected uses or years' and detailing the return values (cost per use and break-even use count), though the 'years' mention slightly deviates from the schema.

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 computes cost-per-use for value evaluation. It identifies the resource (cost-per-use of a purchase) and differentiates from siblings by referencing list_bundles, though it does not explicitly distinguish from all sibling calculators.

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 explicitly says 'Use for buying decisions on durable goods or subscriptions,' providing clear when-to-use guidance. It does not state when not to use or enumerate alternatives beyond list_bundles, but the context is adequate.

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