Try free

Your own plan,
inside Claude or ChatGPT.

Ask questions about your real plan and budget, and let your AI make changes: budgets, categories, rules, scenarios. 100+ tools, and every change is logged, with an undo until you edit it again.

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What your AI would do

You

Can I retire at 56 if I spend $300 a month less?

What the assistant did

  1. get_my_budgetRead your budget: $4,500 a month, with dining out at $270 and shopping at $270.
  2. create_scenarioSaved two what-ifs next to your plan, not over it: retiring at 56, and the same with $300 less a month. Each is logged with an undo.
  3. run_my_monte_carloRan each what-if through random markets: 80 in 100 lasted, and 95 with the smaller budget.
  4. update_budget_amountsPrepared the change below as a preview.

Your AI

Yes, it could. With $300 less a month, retiring at 56, your money lasts the whole plan in 95 of 100 market runs, up from 80. Dining out and shopping are the easiest to trim, so I’d take $150 from each. Want me to make the change?

Dining out$270 → $120

Shopping$270 → $120

Your budget doesn’t change until you say yes.

That’s what your AI could answer once cinder.fi is connected with Pro, worked out for the homepage’s example household with the same engine. Change the answers on the homepage and this conversation uses yours.

Free connections can read your plan, 5 calls a day. Pro adds Monte Carlo, changes and 500 calls a day. Dining out and shopping here are a typical share of the monthly spending; your AI reads your real budget.

Assumes 6% a year on retirement savings and 2.5% inflation, shown in today’s dollars. An estimate, not financial advice.

Connect in a minute

Add cinder.fi to your AI app with one address, then sign in to your cinder.fi account. The connection can only see your account.

Server address

https://mcp.cinder.fi/mcp

Claude

Open Claude connectors
  1. Click “Add custom connector”.
  2. Name it cinder.fi and paste the server address above.
  3. Click Add, then Connect and sign in to cinder.fi (or create a free account).

If Claude asks how it should identify itself, choose “Register automatically”.

Free Claude plans allow one custom connector. On Team and Enterprise, an Owner adds it under Organization settings.

ChatGPT

  1. In ChatGPT settings, turn on developer mode (under Apps & Connectors › Advanced). Availability depends on your plan, and Business and Enterprise admins may need to allow it.
  2. Create a connector with the server address above.
  3. Sign in to cinder.fi.

A one-click ChatGPT app is on the way.

Cursor

Add to Cursor
  1. Click the button and confirm the install in Cursor.
  2. Connect the cinder.fi server and sign in.

VS Code

Add to VS Code
  1. Click the button and confirm the install in VS Code.
  2. Start the cinder.fi server and sign in.

Claude Code

Run this in your terminal

claude mcp add --transport http cinderfi https://mcp.cinder.fi/mcp
  1. Run the command, then type /mcp inside Claude Code.
  2. Choose cinderfi and sign in to cinder.fi.

Any other app that speaks MCP works with the same server address. If it cannot sign in, use an API key (see developer setup below).

Connections start read-only. A free account gets 5 calls a day. Pro gets 500 and can switch changes on per connection in Settings › Ask cinder & agents › Connected agents.

Questions it can answer

  • “How much contribution room do I have left this year?”get_my_contribution_room
  • “Which categories went over budget last month?”budget_variance
  • “Why did my net worth change last month?”explain_balance_change
  • “How long would my cash last if I stopped working?”cashflow_runway

Changes it can make, with your OK

  • “Move $200 a month from dining out to savings.”Shown as a preview first. Nothing changes until you say yes.
  • “Make a rule so Costco is always groceries.”Saved as a rule, with an undo. Applying it to past transactions is a separate step you can preview.
  • “Try retiring two years later as a scenario.”Saved as a scenario next to your plan, not over it.

What a connection can and can’t do

A connection signs in as you and sees only your household’s data. It starts read-only, and an assistant can change nothing until you turn changes on for that connection.

Every change is logged with what it replaced, and you can undo it from your AI or in Settings, as long as nothing has edited it since.

If you use an encrypted mode, a connected AI gets only the calculators. It can’t read your financial data.

Read your plan. Change it. Check the math.

More than 100 tools: the calculators, plus tools that read and change your saved plan. Here is a sample.

Your plan: ask

  • get_my_planYour saved plan and its inputs
  • get_my_budgetYour budget by category and month
  • get_my_accountsAccounts, balances and net worth
  • get_my_projectionYour projection and key ages
  • search_transactionsSearch your transactions
  • get_my_contribution_roomContribution room by account type

Your plan: change

Pro
  • update_my_inputsChange plan inputs, previewed first
  • update_budget_amountsAdjust budget amounts by category
  • upsert_category_ruleCreate or edit a categorization rule
  • create_scenarioSave a what-if scenario
  • add_transactionAdd a transaction by hand
  • undo_changeReverse a change by its id

Projections & Analysis

  • run_projectionYear-by-year retirement projection
  • run_full_analysisProjection + score + insights in one call
  • calculate_scorecinder score 0–100 retirement readiness
  • generate_insightsPersonalized optimization recommendations

Tax & Benefits

  • calculate_taxIncome tax for any province or US state
  • calculate_dividend_taxCanadian dividend tax with gross-up and credit
  • estimate_benefitCPP/OAS or Social Security with claiming age
  • calculate_cpp_timingCPP and OAS claiming ages compared
  • calculate_ss_timingSocial Security 62–70 vs full retirement age
  • calculate_gisGIS eligibility, clawback & provincial supplement
  • calculate_meltdownRRSP meltdown / Roth conversion strategy

Spending & Impact

  • simulate_purchaseRetirement cost of a one-time or recurring expense
  • simulate_windfallOptimal allocation for an inheritance or bonus
  • compare_spending_strategiesFixed / Guyton-Klinger / VPW comparison
  • map_financial_dataConvert YNAB/bank exports to cinder.fi inputs

Pro calculators

Pro
  • run_monte_carloProbabilistic success with percentile outcomes
  • optimize_withdrawal_orderBest CPP/SS timing + withdrawal strategy
  • run_backtestEvery historical window since 1928
  • compare_scenariosSide-by-side 1–4 scenario comparison
  • optimize_pension_splitMinimize combined tax via pension income splitting

The calculators take couples on every tier. Reading your own data needs a key or connection tied to your account. Making changes needs Pro and a switch you turn on.

API keys and calculators

  1. 1

    Get an API key

    A free key runs the calculators: 5 calls a day, no credit card. To reach your own data, create a personal key in Settings › Ask cinder & agents › API.

    Get a free key →

  2. 2

    Add it to your config

    One JSON block into Claude Desktop, Claude Code, Cursor or any MCP-compatible host. Swap in your key and you’re live.

    See configs →

  3. 3

    Ask anything

    Your agent can call the cinder.fi tax engines, projection models and optimizers.

    View docs →

Retirement math,
inside your AI.

Ask about CPP timing, run Monte Carlo, or find out what a $70K car costs your retirement.

Get a free API keyView on GitHub ↗

MCP Tool

run_monte_carlo

87%

success rate

1,000 simulations complete. At the 10th percentile you run out at 82. Cutting $400/mo spending pushes success to 91%.

Drop it in and you’re done

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "cinderfi": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.cinder.fi/mcp"],
      "env": {
        "AUTHORIZATION": "Bearer YOUR_API_KEY"
      }
    }
  }
}

File location: ~/Library/Application Support/Claude/claude_desktop_config.json (macOS)

Endpoint: https://mcp.cinder.fi/mcp
Auth: Authorization: Bearer <api-key>
Transports: Streamable HTTP, SSE

Full documentation and agent skills: GitHub

Get your API key

Free key: 5 calls a day, no credit card required.

Already have a cinder.fi account? Manage your key →

Simple, transparent

MCP Free

$0 forever

Calculators with full tax engines for Canada and the US, plus read-only access to your own plan.

Get a free key
  • ✓ Tax, benefit and projection calculatorsCouples included, CA + US tax engines
  • ✓ Read your own planBudget, accounts, projection, contribution room
  • ✓ 5 calls a dayA free key needs no credit card
  • — Monte Carlo, optimizer, backtest
  • — Changes and undo

MCP Pro

$5/mo

Billed monthly

Everything in Free, plus changes and the heavy tools: Cut my dining budget. File this payee under groceries. What’s my Monte Carlo success rate?

Get MCP Pro
  • ✓ 500 calls a dayRoom for a long conversation
  • ✓ Changes, with undoBudgets, categories, rules, scenarios, accounts
  • ✓ All 100+ toolsIncluding every Pro calculator
  • ✓ Monte Carlo and backtestOn any inputs or on your saved plan
  • ✓ Withdrawal optimizerCPP/SS timing + order + meltdown

Already a cinder.fi Pro subscriber? MCP access is included with your plan. Connect your AI above.

Your AI, with
your real numbers.

Connect cinder.fi, ask about your plan, and undo anything you don’t like.

Connect your AI