How Cheapli works

What MCP is, in sixty seconds

The Model Context Protocol is a standard way for an AI assistant to use outside tools. A server publishes a list of tools with typed inputs; the assistant reads that list, decides when a tool is relevant, calls it, and reads the result back into its answer.

You never call Cheapli yourself. You ask your assistant a question in English — "can these two service $850k across the panel?" — and it works out that run_serviceability is the tool for the job, fills in the scenario, and explains the result.

Connect your agent

Pick your client. Replace $CHEAPLI_URL with the endpoint from your access email and $CHEAPLI_TOKEN with your token.

claude mcp add --transport http cheapli $CHEAPLI_URL/mcp \
  --header "Authorization: Bearer $CHEAPLI_TOKEN"

# then just ask:
#   "run serviceability for a couple on 125k and 78k,
#    one dependant, buying at 1.1m in NSW"

{
  "mcpServers": {
    "cheapli": {
      "type": "http",
      "url": "$CHEAPLI_URL/mcp",
      "headers": {
        "Authorization": "Bearer $CHEAPLI_TOKEN"
      }
    }
  }
}

# Prefer to keep scenarios on your own machine?
# Cheapli runs over stdio with no network hop at all.
npm install
npm run pipeline cdr        # seed carded rates from public open-banking APIs
claude mcp add cheapli -- npx tsx src/server/stdio.ts

curl -s $CHEAPLI_URL/mcp \
  -H "Authorization: Bearer $CHEAPLI_TOKEN" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize",
       "params":{"protocolVersion":"2025-03-26",
                 "capabilities":{},
                 "clientInfo":{"name":"curl","version":"1"}}}'

# keep the mcp-session-id response header, send it on every
# following request (tools/list, tools/call, …)

Tokens and fair use

Access is a bearer token sent on every request. Request one here — we send the endpoint and the token by email, and we don't charge for it. If a token leaks, tell us and we'll roll it.

Tool reference

Your assistant reads these definitions automatically. They're here so you know what it can do — and so you can check its homework.

{
  "lenderId": "anz",
  "status": "pass",
  "maxBorrowing": 951044,
  "monthlySurplus": 0,        // solving max drives surplus to ~0
  "dti": 4.44, "dtiCap": 7.5, "lvrPct": 86.5,
  "productRatePct": 6.54, "assessedRatePct": 9.54,
  "bindingConstraint": "surplus",
  "breakdown": { "incomeLines": [ … ], "commitments": [ … ],
                  "expenseFloorUsed": "hem", "hemMonthly": 4350 },
  "appliedPolicies": [
    "Declared expenses below benchmark — HEM floor of $4350/mo applied",
    "HECS/HELP assessed at statutory marginal repayment rates", … ],
  "drivers": [ "assessment rate 9.54% is 0.40% above the median" ],
  "modelVersion": "2026.07.0",
  "verifiedAgainst": { "source": "public calculators, broker policy pages, APG 223",
                       "date": "2026-07-14" },
  "disclaimer": "Estimate only — modelled from public sources …"
}

Resources

Alongside tools, Cheapli publishes documents an agent can read directly:

Where the numbers come from

Each lender assessment runs the same seven steps. Nothing is hidden in a black box — every step appears in the response.

1. Recognise income. Each income type is shaded to that lender's policy — overtime, bonus, commission, casual, rental and self-employed all get different treatment, and some occupations get different treatment again.
2. Tax it. Individual income tax, Medicare levy and the low-income offset are applied per applicant on the recognised gross, not the declared gross.
3. Floor the expenses. The greater of declared living expenses and the household benchmark for that family size and income band.
4. Buffer the commitments. Existing mortgages re-amortised at a buffered rate, credit cards at a percentage of limit whether or not they're used, personal loans at actual or buffered repayments, HECS from assessed income.
5. Assess the new loan. Repayment computed at the greater of the product rate plus the lender's buffer and the lender's floor rate.
6. Take the surplus. Net income minus expenses, commitments and the assessed new repayment.
7. Solve the maximum. A binary search for the largest loan that keeps the surplus non-negative, capped by that lender's LVR and debt-to-income ceilings — the response says which of the three actually bound.

Rates come from public open-banking product data, refreshed daily, with the last known good set kept if a refresh fails. Lender models are hand-built from public material, version controlled, and changed only by review — a detected policy change raises a flag for a human, it never edits itself.

What this is not

• Not advice. Cheapli does not provide financial product or credit advice, and is not a credit assistance service.
• Not a system of record. Nothing you send is stored. If you need an audit trail, keep it in the system you already use for that.
• Not exact. Real assessments include documents, credit history, valuations and judgement. Treat every figure as a starting point to verify.