SKILL.md
Budget Builder Skill
Most budgets fail because they're aspirational fiction. This skill builds a realistic monthly budget from someone's actual income and spending — categorized, with a clear surplus-or-shortfall number and a couple of specific moves to fix the gap. It's an educational planning aid, not personalized financial advice.
Required Inputs
Ask for these only if they aren't already provided:
- Monthly take-home income (after tax), and whether it's steady or variable.
- Fixed costs — rent/mortgage, utilities, insurance, loan/debt minimums, subscriptions.
- Variable spending — groceries, transport, eating out, fun, shopping (estimates are fine).
- Goals & obligations — emergency fund, debt payoff, saving for something, dependents.
If numbers are rough, work with ranges and say so.
Output Format
Monthly budget — [name/household]
Income (take-home): $X
| Category | Type | Amount | % of income |
|---|---|---|---|
| Housing | Need | $ | % |
| Utilities & bills | Need | $ | % |
| Groceries | Need | $ | % |
| Transport | Need | $ | % |
| Debt minimums | Need | $ | % |
| Dining / fun | Want | $ | % |
| Subscriptions | Want | $ | % |
| Savings / goals | Save | $ | % |
| Total | $ | 100% |
Needs / Wants / Savings split: X% / Y% / Z% — with a one-line read vs. a 50/30/20 guideline (a reference point, not a rule).
Bottom line: surplus of $X (allocate it) or shortfall of $X (must cut/earn).
Top 3 moves — the specific, highest-impact changes (e.g. "renegotiate the $X subscription stack", "cap dining at $Y", "auto-transfer $Z on payday").
Notes — assumptions, and for variable income, budget against a conservative (low) month.
Quality Checks
- Every dollar is assigned (expenses + savings = income; surplus/shortfall is explicit)
- Categories are split into needs / wants / savings, with percentages
- The plan is realistic for their actual spending — not an aspirational fantasy
- Variable income is handled conservatively (budget the low month)
- The top moves are specific and quantified, not "spend less"
Anti-Patterns
- Do not present a budget that doesn't balance to income — name the surplus or shortfall
- Do not set unrealistic cuts that won't survive week one — anchor to their real numbers
- Do not ignore irregular costs (annual insurance, holidays) — prorate them monthly
- Do not give generic advice — every recommendation should reference their figures
- Do not present this as personalized financial advice — it's an educational plan to adapt
Based On
Personal budgeting practice (zero-based budgeting + the 50/30/20 needs/wants/savings guideline).