Car Lease Decoder Skill

Leases are quoted in a dialect designed to prevent comparison: money factors instead of interest rates, cap costs instead of prices, payments instead of totals. This skill translates everything into the two numbers that matter — the effective APR and the total cost of the lease — then walks the traps that live in the back pages.

What This Skill Produces

• The translation — money factor × 2400 = the APR they didn't say; cap cost vs MSRP vs negotiated price
• Total lease cost — payments + drive-off + fees + likely end charges, one number
• The trap list — mileage math, disposition fee, wear-and-tear standards, early-exit exposure, each priced
• Negotiation points — what's routinely movable, with the asks

Required Inputs

Ask for these only if not provided:

• The offer sheet — payment, term, miles/year, drive-off; ideally: money factor, residual %, cap cost, fees
• The car — model and MSRP (residuals and negotiability vary)
• Your driving reality — honest annual miles; the mileage trap is priced per your number
• The alternative — buying the same car, if they want the comparison (chain to car-tco)

Framework

1. Money factor first: MF × 2400 = APR. Quote it back to the dealer as a rate. A "0.00325 money factor" is 7.8% — a number the customer can compare to their credit union. Also ask what MF the captive lender published — marked-up MF is dealer profit and negotiable.
2. The lease equation, shown: depreciation (cap cost − residual) + rent charge ((cap + residual) × MF) + taxes/fees. Every offer decodes into this; anything that doesn't reconcile is a question.
3. Cap cost is the price — negotiate it exactly like a purchase price before ever discussing payment. "What payment do you want?" is the trap question; the decode answers with cap cost.
4. The mileage math, personalized: (your real miles − allowance) × per-mile charge × term. At 15k real vs 10k leased and $0.25/mile, that's $3,750 hiding behind a cheaper payment.
5. The end-of-lease gauntlet: disposition fee, wear standards ("excessive" defined by whom?), and the early-exit table — decode each with its dollar exposure and the one protective ask (e.g., waived disposition if leasing again).

Output Format

Lease Decode: [car] — [term]/[miles]

The two numbers: effective APR [n.n]% · total lease cost $[n] ([payments] + [drive-off] + [fees] + [projected end charges])

The equation, reconciled [depreciation + rent charge + fees vs their payment math — matches / gap of $n asks why] Trap table | Trap | The line | Your exposure | The ask | Negotiation points — cap cost, MF markup, mileage tier, disposition — each with wording Lease vs buy pointer: [one honest paragraph; full math via car-tco]

End verbatim: "This is a plain-language reading, not financial advice — lease structures and taxes vary by jurisdiction; confirm anything load-bearing before signing."

Quality Checks

• The money factor is converted to APR and the markup question is raised
• Total lease cost is computed, not just the payment
• Mileage exposure uses the user's real miles
• Every trap carries a dollar exposure and a protective ask
• The disclaimer appears verbatim

Anti-Patterns

• Do not evaluate the payment — payments are the costume; APR and total cost are the deal
• Do not accept the money factor as a mystical constant — it's a rate with a markup
• Do not use the leased mileage in the math — use the driven mileage
• Do not ignore the end-of-lease pages — that's where the cheap payment gets paid back
• Do not declare lease vs buy universally — it depends on miles, years, and taxes; point to the calculator