複利計算（一括 + 月次積立）

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

No annotations are provided, and the description does not disclose behavioral traits such as whether the tool is read-only, any rate limits, or side effects. Since it is a calculation tool, it is likely safe, but the description does not confirm this or address any potential limitations.

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 a single sentence followed by a clarifying second sentence. It is extremely concise, front-loaded with the core action, and contains no unnecessary words or redundancy.

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 has no output schema, so the description should ideally hint at the output format or values. It only mentions 'future value' without further details. The description is adequate for a simple calculator but lacks completeness regarding the return structure.

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 schema covers all 4 parameters with descriptions (100% coverage). The description adds context about monthly compounding and general applicability, but it does not significantly enhance understanding beyond the schema. The baseline of 3 is appropriate as the schema already provides adequate meaning.

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 calculates the future value of a lump sum principal and monthly contributions with monthly compounding. It explicitly mentions it is a general-purpose tool for investment and time deposit simulations, which distinguishes it from sibling tools like 'calculate_required_monthly' that perform reverse calculations.

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 compound interest simulations and mentions it is usable for NISA and general investments, but it does not provide explicit guidance on when not to use this tool or name alternatives. The context is clear but lacks exclusions or comparative statements.

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