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

With no annotations provided, the description carries the full burden. It discloses that it uses the latest CDN inflation rate for the inflation-adjusted value, which is a non-obvious behavior. However, it does not mention any side effects (none expected for a calculator) or potential data source dependencies beyond the inflation rate, which is a minor gap.

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 compact: two sentences, front-loaded with the core purpose, and each phrase adds value. It avoids fluff and clearly communicates the tool's function and a key data source in minimal words.

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 calculator tool with no output schema and full parameter schema documentation, the description is quite complete. It mentions the return values and a key external data source (CDN inflation rate). Missing details like whether monthly contributions are added at the beginning or end of the period are minor and not critical for typical use.

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 100%, so the schema already documents all parameters. The description adds meaningful context by mentioning 'monthly contributions' and 'inflation-adjusted value', clarifying that monthlyContribution is supported and that inflationRate affects the output. This adds value beyond the basic schema 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?

The description clearly states the tool's purpose: compound interest with monthly contributions, and explicitly lists the return values (final balance, total interest, inflation-adjusted value). It is distinct from the many sibling tax and ROI calculators, focusing on a specific financial calculation.

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 implies usage for financial planning scenarios involving compound interest and contributions, but does not explicitly state when to use this tool versus alternatives like calculate_roi or calculate_freelancer_pricing. It lacks explicit exclusions or alternative guidance, though the purpose is clear enough to infer common use cases.

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