Budget Builder and Narrative
Structure a budget and write the narrative that explains and defends its assumptions.
Get the Budget Builder and Narrative skill
Install it in Claude as an Agent Skill, or copy it into ChatGPT, Gemini, or any assistant. Same method either way.
This is a drafting and analysis aid. It produces a first draft for a qualified professional to review. It is not financial, accounting, tax, or investment advice.
What this does and why it matters
A budget without a rationale is just a wish list that gets cut arbitrarily. This skill structures a budget and, crucially, writes the narrative that explains the assumptions behind each line, so the budget is defensible, understood, and more likely to survive review. The narrative is what turns numbers into a plan stakeholders buy into.
Inputs to gather
- The period and scope (whole company, department, project).
- The revenue or funding assumptions.
- The cost drivers and planned spend by category.
- Prior actuals, for grounding.
- The strategic priorities the budget should fund.
Method
1. Anchor to priorities
A budget is strategy expressed in dollars. Tie spend to the priorities it funds, so reviewers see what each line buys, not just what it costs.
2. Make assumptions explicit
Every significant line rests on an assumption (headcount, growth rate, unit cost, timing). State them, because a budget is only as credible as its stated assumptions, and unstated ones invite suspicion.
3. Ground in history where possible
Compare to prior actuals and explain material changes, so the numbers feel evidence-based rather than pulled from air.
4. Build in reality
Flag where estimates are uncertain and where contingency is prudent, rather than presenting false precision.
5. Write the narrative per section
For each major category, a short rationale: what it funds, the key assumption, and why the amount. This is the defensible core.
Output format
ALWAYS use:
# Budget: [Scope] | [Period]
## Overview (what this budget funds, top-line totals)
## Revenue / funding assumptions
## Expense plan by category (category | amount | vs prior | key assumption)
## Narrative by section (rationale for each major line)
## Key assumptions summary
## Contingency and areas of uncertainty
Anti-patterns to avoid
- Numbers with no stated assumptions.
- No comparison to prior actuals.
- False precision that hides real uncertainty.
- Spend disconnected from any priority.
Guardrails
This structures figures and assumptions the user provides; it is not financial advice. Never invent figures or assumptions; use placeholders for anything missing and flag it. The user is responsible for the accuracy of the underlying numbers.
Example
A department budget ties each line to a priority, states the headcount and unit-cost assumptions behind the largest categories, compares to last year with explanations for the increases, and flags one uncertain vendor cost with a contingency.
How to use this skill
- Download the SKILL.md file above.
- Add it to a Claude environment that supports Agent Skills, or attach the file to your conversation.
- Make your request and hand over the raw input. Claude triggers the skill automatically.
- Copy the skill text above.
- Paste it into a ChatGPT Project, a Custom GPT's instructions, or a Gemini Gem.
- Give the model your raw input. It follows the same method and output format.
Frequently asked questions
What does the Budget Builder and Narrative skill do?⌄
Structure a budget and write the narrative that explains and defends its assumptions. Use this skill whenever a user is building a budget, needs a budget narrative or justification, is planning next year's spend, or says 'help me build our budget', 'write the budget narrative', or 'justify these numbers'. Trigger whenever budget figures need structure and a written rationale that stakeholders will accept.
How do I use the Budget Builder and Narrative skill in Claude?⌄
Download the SKILL.md file and add it to a Claude environment that supports Agent Skills, or attach the file to your conversation. Claude triggers the skill automatically when your request matches what it does, then returns a structured first draft.
Can I use the Budget Builder and Narrative skill in ChatGPT or Gemini?⌄
Yes. Copy the skill text and paste it into a ChatGPT Project, a Custom GPT's instructions, or a Gemini Gem. Then give the model your raw input and it follows the same method.
Is the Budget Builder and Narrative skill free?⌄
Yes. Every skill in the library is free and ungated. Download it, copy it, and use it however you like.
Is the Budget Builder and Narrative skill financial or professional advice?⌄
No. Regulated skills produce first drafts and analysis for a qualified professional to review. They do not replace professional judgment and are not financial, accounting, tax, or investment advice.
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