SmartTools

Compound interest calculator

compound_interest_calculator

Future balance and interest earned: A = P(1 + r/n)^(nt). Runs on smart-tools.xyz.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "principal": "<principal>",
      "annual_rate": "<annual_rate>",
      "years": "<years>"
    },
    "name": "compound_interest_calculator"
  }
}

Input Schema

Name	Required	Description
`years`	Yes	Number of years
`locale`	No	Language for the source_url link (default en)
`principal`	Yes	Starting amount
`annual_rate`	Yes	Annual rate, percent
`compounds_per_year`	No	Compounding periods per year (default 12)

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 17, 2026

TDQS

B3.1/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It mentions the formula and 'Runs on smart-tools.xyz' but does not disclose whether the result is a single value or two outputs, rounding behavior, or handling of invalid/edge-case inputs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is short and front-loaded with the core purpose and formula. However, the second sentence 'Runs on smart-tools.xyz' is filler that does not help an agent select or invoke the tool, preventing a perfect score.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description lacks details about the output structure (does it return both future balance and interest earned?), locale parameter effects, parameter constraints (e.g., positive values), or any error handling. For a no-output-schema tool, this is a significant gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so parameters are already well-documented. The formula adds context relating principal, rate, and compounding periods, but this is marginal beyond the schema's own descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool computes future balance and interest earned, with an explicit formula. This distinguishes it from sibling calculator tools and uniquely identifies its function.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided for when to use this tool versus alternative calculators, nor are there any exclusions or prerequisites. The intended use is only implied by the name and formula.

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

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