Source: https://guthlabs.ai/docs/instruments/monte-carlo-retirement-simulator/implementation/

instrument implementation / implementation-contract

# Monte Carlo Retirement Simulator implementation

A source-bound implementation contract for Monte Carlo Retirement Simulator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-061

**Effect**: Computation or source lookup only

## Input and validation requirements

The extreme-magnitude vector produces approximately 1e616, which overflows standard JavaScript Number arithmetic to Infinity. The specification also leaves withdrawal timing and return-unit conventions underspecified, allowing materially different balances for the same apparent inputs.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "starting_balance": 100000,
    "withdrawal_amount": 5000,
    "mean_return": 0.05,
    "volatility": 0,
    "years": 3,
    "trial_count": 100,
    "withdrawal_timing": "end_of_year",
    "return_model": "simple_annual",
    "return_draws": [
      0.05,
      0.05,
      0.05
    ]
  },
  "expected_outputs": {
    "success_probability_percent": 100,
    "balance_percentiles": {
      "p5": [
        100000,
        99750,
        99487.5,
        99211.875
      ],
      "p50": [
        100000,
        99750,
        99487.5,
        99211.875
      ],
      "p95": [
        100000,
        99750,
        99487.5,
        99211.875
      ]
    }
  },
  "working": "All 100 trials are identical because sigma=0. Year 1: (100000-5000)*1.05 = 95000*1.05 = 99750. Year 2: (99750-5000)*1.05 = 94750*1.05 = 99487.5. Year 3: (99487.5-5000)*1.05 = 94487.5*1.05 = 99211.875. Every withdrawal is affordable, so 100 of 100 trials succeed and every percentile equals the common path."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/monte-carlo-retirement-simulator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/monte-carlo-retirement-simulator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/monte-carlo-retirement-simulator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`