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

With no annotations, the description carries the full behavioral burden. It discloses the paid nature and cost (0.001 USDC per call via x402) and mentions the year-by-year schedule output, but it does not explain the payment workflow, rate limits, or that the operation is purely computational.

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 compact sentences with no wasted language. The core purpose is front-loaded, followed by the cost disclosure.

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 description covers the main result and the per-call cost, and the schema supplies most parameter details. However, with no output schema and no annotations, it should more fully explain the payment-proof workflow and the meaning of periodsPerYear for compounding frequency.

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 description coverage is high at 83%, so the schema already documents most parameters. The description adds conceptual context by referencing principal, periodic contributions, and compounding, but it does not clarify the undocumented periodsPerYear parameter or add syntax beyond 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 computed result: future value of a principal with periodic contributions and compounding, plus a year-by-year schedule. It is specific enough to distinguish this from generic arithmetic tools, though it does not explicitly differentiate from finance siblings like apr_apy or dca_plan.

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 gives no explicit guidance on when to use this tool versus alternatives, nor does it state prerequisites or exclusions. The implied use case is compound-interest projection, but there is no routing guidance among the many finance-related siblings.

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