# Driver Based Budget Builder

> Builds a monthly budget from real volume, price, and department cost growth drivers via a bundled calculator, phased across the year, instead of the "last year plus X%" shortcut that hides every real assumption behind one blended growth rate. Use whenever the user is building an annual or departmental budget, needs a phased monthly plan rather than a single annual number, or has a budget built as…

- **Type:** Skill
- **Install:** `agentstack add skill-natan-mohart-24-finance-skills-for-claude-driver-based-budget-builder`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [Natan-Mohart](https://agentstack.voostack.com/s/natan-mohart)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [Natan-Mohart](https://github.com/Natan-Mohart)
- **Source:** https://github.com/Natan-Mohart/24-finance-skills-for-claude/tree/main/skills/driver-based-budget-builder

## Install

```sh
agentstack add skill-natan-mohart-24-finance-skills-for-claude-driver-based-budget-builder
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Driver-Based Budget Builder

## When to use
Use whenever a budget needs to be built or rebuilt from real drivers rather than "take last year and add X%" — a shortcut that hides whether growth is coming from volume, price, or something else, and applies the same blended assumption to every department regardless of what actually drives its cost.

## What it does
Builds a phased, monthly budget from explicit revenue drivers (starting volume, volume growth rate, price, and timed price changes) and department-level cost growth rates via a bundled calculator, producing a full monthly build with revenue, opex by month, and EBITDA, rather than a single annual figure with no visibility into how it's phased.

## Method
1. **Decompose revenue into volume and price separately**, never a single blended revenue growth rate. State the starting volume, the monthly volume growth rate, the starting price, and any planned price changes with their timing (many businesses change price once a year, not continuously — model it as a discrete jump on the right month, not smoothed across twelve months).
2. **Build cost by department, not one company-wide opex line.** Each department has a different natural growth rate: R&D might scale with headcount plans, G&A might grow slower than revenue, sales and marketing might scale with the pipeline the growth target requires.
3. **State each department's monthly growth rate explicitly**, tied to a real driver (headcount additions, planned tooling costs, marketing spend as a percent of pipeline target) rather than a copied-forward percentage.
4. **Run the bundled calculator** (`scripts/driver_budget.py`) to get the full monthly build: units, price, revenue, total opex, and EBITDA for every month of the year.
5. **Check the phased shape, not just the annual total.** A budget that's flat month to month rarely matches how a real business actually grows — look for whether the monthly progression makes sense (seasonality, a price increase landing on a specific month, ramping costs ahead of a launch).
6. **Sanity-check the full-year EBITDA margin against what's actually achievable** — a budget that implies a margin far outside historical range or peer benchmark needs its drivers revisited, not just accepted because the formula produced it.
7. **Feed this bottom-up build into annual-operating-plan** to reconcile against any top-down target leadership has in mind, rather than treating this build as the final published budget on its own.

## Inputs
- Starting volume/units and monthly volume growth rate
- Starting price and any planned price changes with timing
- Department list with starting monthly cost and monthly growth rate per department
- Config saved as JSON matching the format documented at the top of `scripts/driver_budget.py`

## Output format
Full monthly table: units, price, revenue, total opex, and EBITDA for every month; full-year totals; full-year EBITDA margin.

## Example
A budget built as "last year's $3.2M revenue plus 20%" gives one number with no way to check if it's realistic. Rebuilding from drivers, 1,000 starting units growing 4% monthly with a 3% price increase in month 7, produces $3.82M with visibility into exactly when and why revenue accelerates, plus a full monthly opex build showing the business runs at a -68% EBITDA margin for the year, a number worth challenging on the cost side before the budget is finalized, not something a single blended annual figure would have surfaced.

## Common pitfalls
- Building revenue as one blended growth rate instead of separating volume and price, which hides which lever is actually doing the work.
- Applying the same growth rate to every department instead of driver-based rates per department.
- Publishing only the annual total without the monthly phasing, missing whether the shape of the year actually makes sense.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [Natan-Mohart](https://github.com/Natan-Mohart)
- **Source:** [Natan-Mohart/24-finance-skills-for-claude](https://github.com/Natan-Mohart/24-finance-skills-for-claude)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-natan-mohart-24-finance-skills-for-claude-driver-based-budget-builder
- Seller: https://agentstack.voostack.com/s/natan-mohart
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.