Assets, priced and dated.
You can import your investment portfolio and trade history to aggregate and maintain your balance across different accounts — daily stock price updates reflect the current value of your holdings. Alternatively, you can plan from a single total and a % of stocks, bonds, and cash. It's easy to get started.
A plan you describe by what you spend.
Most retirement calculators ask for a target income and then check whether you can withdraw it, which is circular — you guess a number and the model scores your guess. This one asks what the household spends: a baseline, the step down as each child becomes independent, the years a wedding or a new roof lands in. It asks what the household earns. Then the portfolio funds the difference across 1,000 simulated markets. Two people retiring three years apart is something you can simply say.
Then see where every dollar goes.
The success percentage is not the whole answer, so beside it sits the path the plan expects: the whole arc on one chart with the years something happens marked, any one of those years opened up to show where its money came from and where it went. Withdrawals come out of three real buckets — taxable, tax-deferred, and Roth — with early-withdrawal penalties and required minimum distributions keyed to each owner's own age rather than one blended rate for the household.
Your own files. No bank logins.
You are never asked for a brokerage password, and no third party holds a standing connection to your accounts. Your history goes in as a plain CSV and you can use an AI assistant to generate the import format from your broker's export, or enter trades one at a time. Your data is never locked in and can be exported at any time.
Bring your own agent.
Point Claude, or any MCP client, at your own household and ask it your own questions: what happens if we retire two years earlier, what does the health-insurance bridge actually cost, which holding is showing no value. It can record trades and import a CSV too. The server is hosted, so there is nothing to install. In Claude Code it is one line:
claude mcp add --transport http --scope user inv https://mcp.inv.randomfact.comThen run /mcp in a new session and sign in through the browser tab that opens. In Claude Desktop or on claude.ai, add https://mcp.inv.randomfact.com under Customize → Connectors as a custom connector instead. Either way the assistant acts as you — same Google account, same household, same role — so a viewer's agent reads everything a viewer can and writes nothing. It arrives already knowing how the app works, so you ask for the outcome rather than the API call.
Explanations throughout.
Any change to the model automatically recalculates the plan so you can see the impact in real time. Market assumptions can be adjusted based on industry standards or your own research. Review the documentation for details on how the plan works and what the model accounts for.
Read it before you trust it
- Getting startedThe first account, the first import, the first plan.
- Portfolio and cashHow the dashboard's number is built, and what the date means.
- Monte Carlo and scenariosWhat the percentage is, and how to try an alternative safely.
- How the plan is simulatedEvery formula, with a real number worked through it.
- What the model leaves outThe simplifications, each with the direction of its error.
- Connect your AI assistantSetting up MCP, and what is actually worth asking it.
Start with what you already have.
Add an account, drop in a CSV, and the plan has a real portfolio to run over. It is a planning tool, not financial advice.
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