Local when you want it
Run it locally and your data stays as plain JSON on your disk. Hosted state expires after an hour without use. What we hold, and for how long.
MCP server for AI assistants
Calculations, not hallucinations.
FinPlanTools gives Claude, ChatGPT, and other AI assistants a real calculation engine for personal finance: IRS tables, state tax, Social Security, RMDs, and projections from quick formulas to full Monte Carlo.
Or paste into your assistant
Add the finplan.tools mcp and use it for financial decisions AskYour assistant
Can I take a year off and still retire at 63?
ComputeFinPlanTools
- create_scenario · project_plan
- Monte Carlo simulation
- Goal: retire at 63
AnswerComputed
- Success probability
- 87%
- Median ending balance
- $2.41M
- 10th percentile
- $610K
Why trust it
Cited, not guessed
Federal brackets from IRS publications. Every state and local rate cited to the government that levies it.
Same inputs, same answer
Projections are reproducible and can be pinned to dated snapshots you can diff later.
The problem
Ask an AI about money and you usually get a paragraph.
Language models are good at conversation and bad at tax brackets. FinPlanTools does the arithmetic, so your assistant answers with numbers it can show its work on.
| Question | An LLM alone | With FinPlanTools |
|---|---|---|
| How much tax will I owe? | An estimate from training data. | The IRS brackets for your filing status and year. |
| Can I max out my 401(k)? | A limit that may be out of date. | This year's limit for your age. |
| Will I have enough to retire? | A hedged paragraph. | A projected range of outcomes, from exact formulas or Monte Carlo. |
How it works
Real math, exposed as tools your assistant can call.
Each capability is a typed MCP tool. Your assistant picks the right one, fills in your data, and gets exact numbers back.
- ProjectionsFormulas by default, Monte Carlo when the path matters.
- TaxFederal, all 50 states + DC, local layers, AMT, capital gains.
- AccountsEvery common account type, including debts, each with its tax treatment and rules.
- GoalsTargeted by confidence, funded by earmarked accounts.
- Social SecurityBenefits at every claiming age, spousal and survivor rules.
- RMDsYear-by-year schedules under SECURE 2.0.
- Equity compISO exercises, AMT, qualifying and disqualifying dispositions.
- PortfolioCapital market assumptions, allocations, glide paths.
- MortgagePayments and full amortization schedules.
- BudgetIncome and expenses rolled into a cash-flow timeline.
- SnapshotsPoint-in-time records you can diff.
- ChartsFan charts, projection comparisons, allocation breakdowns.
Composable
Ask the question you actually have.
Each capability is a separate tool, so your assistant can combine them to answer questions nobody designed a screen for.
Question atax · accounts · projections
What if I take a year off and harvest capital gains in the low-income year?
Question btax · accounts · rmd · projections
Should I convert to Roth before RMDs push me into a higher bracket?
Question csocial security · tax · projections
Can I go part-time at 55 and still claim Social Security at 67?
Question dtax · rmd
For the Hendersons: how much to convert to Roth this year before the next bracket, and the break-even against leaving it in the IRA.
Get started
Connected in three steps.
Also works with Claude Desktop, ChatGPT, Gemini CLI, Cursor, Zed.
Add the marketplace
One command in Claude Code.
claude plugin marketplace add bestdan/finplan-plugin Install the plugin
OAuth handles authentication.
claude plugin install finplan@finplan-plugin Run setup
Then ask anything.
/finplan:setup Ask a question with an answer you can show.
Pick your assistant, connect in a few minutes, and try it on sample data first. Free for personal use.