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

The description explains the behavioral trait of compounding (down or up) at a yearly rate, which goes beyond the annotations that only indicate read-only and idempotent. It clarifies that the tool can both depreciate and appreciate based on the 'up' parameter, adding useful context. There is no contradiction with the annotations, and the description enriches the safety profile with method details.

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 two sentences long and front-loaded with the core behavior. Every word contributes: the first sentence states the calculation and the second gives application context. No redundancy or fluff, making it highly concise and well-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 a simple read-only calculation with a complete output schema, and the description explains the core method and typical use case (long-term assets). It does not need to explain return values since the output schema exists. It could mention edge cases (e.g., negative rates) but given the simplicity and available schema, it is sufficiently complete.

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 already documents all parameters with clear descriptions, achieving 100% coverage. The description does not add new individual parameter meaning beyond the schema, but it does provide a high-level formula context (compounding down/up over years). Since the schema handles the heavy lifting, the baseline of 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 what the tool computes: "Value after compounding down (or up) at a yearly percentage rate over a number of years." It identifies the resource (a financial value) and the method (compounding), and distinguishes it from other depreciation methods (e.g., straight-line, declining-balance) by mentioning the ability to appreciate. However, it lacks an explicit verb like 'calculates' or 'computes,' which prevents a top score.

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 provides some usage context with "This is the method the app uses for long-term assets," implying when to use it. However, it does not explicitly compare to alternatives or state exclusions (e.g., when not to use it or which sibling to use instead). The guidance is implied rather than explicit, so it earns a middle score.

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