ScorpTech x402 API

Compound Interest

compound_interest

Read-onlyIdempotent

Compound growth / savings calculator: future value of a principal plus monthly contributions at any compounding frequency (incl. continuous), contributions at start or end of month, inflation-adjusted value, APR <-> APY conversion, doubling time, months to reach a target and a yearly breakdown. Works for savings, staking yields and DCA projections. Price: $0.001 USDC per successful call (x402, Solana). Same tool over HTTPS: GET https://scorptech.it.com/api/x402/v1/compound-interest

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "compound_interest"
  }
}

Input Schema

Name	Required	Description	Default
`years`	No
`apyPct`	No	Effective annual yield in percent (converted to the APR for the compounding)
`target`	No	Optional goal amount: months needed to reach it
`principal`	No
`compounding`	No		monthly
`inflationPct`	No	Annual inflation for the real (today's money) value
`annualRatePct`	No	Nominal annual rate (APR) in percent; or give apyPct
`contributionTiming`	No		end
`monthlyContribution`	No

Schema Changelog

Changes observed during successful MCP inspections.

AddedOct 23, 2026

TDQS

A4.4/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and non-destructive behavior, so the safety profile is covered. The description adds useful operational context: $0.001 USDC per successful call via x402 on Solana and an HTTPS endpoint. It does not describe validation failures, rate limits, or error behavior.

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

Conciseness5/5

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

The description is front-loaded with the core functionality and uses a dense but efficient list of supported computations. The usage sentence and pricing/endpoint sentence each add actionable information with no filler.

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

Completeness4/5

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

For a 9-parameter calculator with no output schema, the description names the expected outputs and computations: future value, doubling time, months to target, and yearly breakdown. It also covers payment and an HTTPS endpoint, but lacks detailed response shape, precision, and error behavior, so it is strong but not exhaustive.

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

Parameters4/5

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

With only 44% schema description coverage, the description helps by explaining APR/APY conversion, inflation-adjusted value, contribution timing, continuous compounding, target months, and monthly contributions. It still leaves some ambiguity, such as what happens if both annualRatePct and apyPct are supplied, and does not fully document every parameter beyond its schema name.

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?

States a specific calculator purpose and enumerates the exact computations: future value of principal plus monthly contributions, multiple compounding frequencies, contribution timing, inflation-adjusted value, APR/APY conversion, doubling time, target months, and yearly breakdown. It also distinguishes intended use cases such as savings, staking yields, and DCA projections.

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

Usage Guidelines4/5

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

The phrase 'Works for savings, staking yields and DCA projections' gives clear usage context. However, it does not explicitly say when not to use it or name alternatives among the many finance-related sibling tools such as loan_amortization or bond_calc.

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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