Skip to main content
Glama

TrueCalci

by com.truecalci
OverviewDiscussionsAdmin

Compound wealth growth

compound_wealth
Read-onlyIdempotent

Standard precision: this calculator uses ordinary floating-point arithmetic, keeps no dated table of official rates, and has not yet passed our full reference-test suite. Simulate long-term compound interest growth for retirement portfolios, 401(k)s, Roth IRAs, UK ISAs, or European ETF savings plans (Sparplan) with recurring monthly deposits.

Behavior: Deterministic, idempotent calculation with zero external side effects. Applies discrete compound interest formula with periodic annuity deposits: Future Value = P*(1 + r/n)^(nt) + PMT(((1 + r/n)^(n*t) - 1)/(r/n)). Returns final accumulated balance, total principal contributed, total compound interest earned, and annual wealth progression milestone table.

Usage Guidelines: Use for multi-year personal wealth projection and retirement nest-egg simulations. Do not use for Indian mutual fund monthly SIPs with annual step-up; use sip_investment instead.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
principalNoInitial lump-sum deposit or starting balance in currency units. Must be non-negative.
tenureYearsYesInvestment horizon in years (e.g. 10, 20, 30). Must be an integer >= 1.
monthlyDepositNoRecurring monthly contribution added to the account. Must be non-negative.
annualRatePercentYesExpected annualized investment return rate percentage (e.g. 8 for 8%). Must be positive.
compoundFrequencyNoNumber of compounding periods per year (1 for annual, 4 for quarterly, 12 for monthly).

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed2 schema fields changed
    • removedInput schema / properties / annualRatePercent / default
      Removed value: -8
    • removedInput schema / properties / tenureYears / default
      Removed value: -15
  2. Changed5 schema fields changed
    • changedInput schema / properties / annualRatePercent / description
      Previous value: -"Expected annual return in %"New value: +"Expected annualized investment return rate percentage (e.g. 8 for 8%). Must be positive."
    • changedInput schema / properties / compoundFrequency / description
      Previous value: -"Compounding frequency per year (12 = monthly)"New value: +"Number of compounding periods per year (1 for annual, 4 for quarterly, 12 for monthly)."
    • changedInput schema / properties / monthlyDeposit / description
      Previous value: -"Monthly recurring contribution"New value: +"Recurring monthly contribution added to the account. Must be non-negative."
    • changedInput schema / properties / principal / description
      Previous value: -"Initial principal deposit"New value: +"Initial lump-sum deposit or starting balance in currency units. Must be non-negative."
    • changedInput schema / properties / tenureYears / description
      Previous value: -"Duration in years"New value: +"Investment horizon in years (e.g. 10, 20, 30). Must be an integer >= 1."
  3. First observed

TDQS

A4.9/5.0
Behavior5/5

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds valuable context beyond these: 'Standard precision: this calculator uses ordinary floating-point arithmetic, keeps no dated table of official rates, and has not yet passed our full reference-test suite.' It also confirms 'Deterministic, idempotent calculation with zero external side effects.' This discloses reliability caveats and confirms behavior without contradicting annotations.

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 structured with a front-loaded caveat, followed by purpose, behavior, and usage. Every sentence adds value: the precision warning is critical, the formula is essential, and the usage exclusion prevents misuse. It is appropriately sized for a tool with 5 parameters and no output schema, with no redundant filler.

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

Completeness5/5

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

Given the tool's complexity (5 parameters, no output schema) and rich annotations, the description fully covers what an agent needs. It explains the return values ('final accumulated balance, total principal contributed, total compound interest earned, and annual wealth progression milestone table'), provides the formula, and sets expectations on precision. Nothing essential is missing.

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?

Schema coverage is 100% and each parameter has a clear description (e.g., annualRatePercent: 'Expected annualized investment return rate percentage'), so the baseline is 3. The tool description adds the exact compound interest formula, which clarifies how parameters interact (e.g., n for compoundFrequency, PMT for monthlyDeposit). This goes beyond the schema's individual parameter descriptions and earns a 4.

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's purpose: 'Simulate long-term compound interest growth for retirement portfolios, 401(k)s, Roth IRAs, UK ISAs, or European ETF savings plans (Sparplan) with recurring monthly deposits.' It uses a specific verb (simulate) and resource (compound interest growth), and differentiates from the sibling sip_investment by explicitly excluding Indian SIPs with step-up. This makes it unambiguous which tool to choose.

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

Usage Guidelines5/5

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

The description provides explicit usage guidance: 'Use for multi-year personal wealth projection and retirement nest-egg simulations. Do not use for Indian mutual fund monthly SIPs with annual step-up; use sip_investment instead.' This clearly states when to use and when not to, and names the alternative tool, leaving nothing to inference.

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

All TrueCalci toolsInspect
Try in Browser
One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources