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compound_interest

Calculate compound interest growth over time. Input principal, annual rate, time period, compounding frequency, and optional monthly contributions to project final value.

Instructions

Calculate compound interest growth over time with optional monthly contributions.

Parameters:
    principal — Initial principal amount.
    rate — Annual interest rate (e.g. 5.0 for 5%).
    time — Time period in years.
    compound — Compound frequency.
    contributions — Optional contribution amount (default: 0).

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>",
      "rate": "<rate>",
      "time": "<time>"
    },
    "name": "compound_interest"
  }
}

Input Schema

Name	Required	Default
`principal`	Yes
`rate`	Yes
`time`	Yes
`compound`	No	annually
`contributions`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.4.1Jun 22, 2026

TDQS

B3.1/5.0

Behavior3/5

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

No annotations are present, so the description carries the burden. It implies a read-only calculation with 'Calculate', but does not explicitly state non-destructive behavior or disclose any side effects. Adequate but not explicit.

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 concise and lists parameters in a structured format. No superfluous information, but it could benefit from a clearer separation between description and parameter list.

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?

Given the complexity of compound interest calculations, the description lacks output details (e.g., result format) and does not address edge cases. This leaves the agent with incomplete expectations.

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?

With 0% schema description coverage, the description adds meanings for all parameters (e.g., rate format, contributions default). However, 'compound' is vague ('Compound frequency') without listing allowed values, reducing clarity.

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

Purpose4/5

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

The description clearly states the tool calculates compound interest growth with optional contributions, using a specific verb and resource. However, it does not differentiate from sibling tools like simple_interest_calc or amortization_calc, which could lead to ambiguity.

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 on when to use this tool versus alternatives. The description does not mention exclusions or prerequisites, leaving the agent without context for selection.

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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