How to use the Startup Financial Modeling agent skill

What is an agent skill, and what does this one do?

An agent skill is a folder of instructions, usually a SKILL.md file with optional reference files, that an AI agent reads when a task matches the skill's description. This skill is a methodology and checklist: it tells the agent how to structure a startup financial plan. It is not a spreadsheet or software tool on its own, so the agent produces the model output itself.

When installed, the agent follows a framework that includes cohort-based revenue forecasts, cost breakdowns by category, cash flow and runway calculations, headcount planning, and conservative (P10), base (P50) and optimistic (P90) scenarios. It also runs sanity checks such as growth rates, LTV/CAC and burn multiple, and gives guidance on modeling fundraising and dilution.

• Revenue: MRR = sum of (cohort size × retention rate × ARPU), with ARR = MRR × 12
• Costs: COGS, Sales & Marketing, R&D and G&A
• Cash: burn = monthly revenue minus monthly expenses; runway = cash balance divided by monthly burn
• Time horizon: monthly detail for Years 1 and 2, quarterly for Year 3, annual for Years 4-5
• Sanity checks against benchmarks such as LTV/CAC > 3, CAC payback < 18 months and burn multiple < 2.0 in Years 2-3

How do you install the startup-financial-modeling skill?

Download the ZIP file from the skill's page on this directory and unzip it. The folder should contain SKILL.md and a references folder with details.md. You can install it in one of two places.

For a personal install, place the unzipped skill folder in ~/.claude/skills/. For a single project, place it in that project's .claude/skills/ folder. Either way, the skill folder should contain SKILL.md.

In the Claude apps, you can instead upload the skill under Settings → Capabilities → Skills.

• Option A: personal install in ~/.claude/skills/
• Option B: project install in the project's .claude/skills/
• Option C: upload through Settings → Capabilities → Skills in the Claude apps

What does the skill need before you start?

The skill lists no required tools or packages. It does not run scripts and does not use the network, so it only supplies instructions to the agent. The quality of the model depends on the inputs you give the agent, so have your real numbers ready.

• Your business model (for example SaaS, marketplace, e-commerce or services)
• Pricing, expected customer acquisition per month and retention assumptions
• Current cash balance, monthly expenses and headcount plans
• Target raise amount and the milestones you want it to reach, if you are fundraising

How do you trigger the skill with a natural request?

You do not need a special command. The skill's description lists the situations it covers, so ask for one of those tasks in plain language. The agent should pick up the skill when your request matches creating projections, calculating burn or runway, modeling fundraising scenarios, or preparing investor-ready financials for a seed or Series A raise.

Give the agent context: your business model, your current cash and your goal. The more specific the request, the more usable the output.

• "Build a 3-year financial model for my B2B SaaS startup with three scenarios."
• "Calculate my runway. I have $400K in the bank and spend $35K a month."
• "Model a $3M seed raise at a $12M pre-money valuation and show dilution."
• "Check whether my LTV/CAC and burn multiple assumptions are realistic."

What does a typical session produce?

Expect the agent to walk through the framework: define the business model, project revenue by cohort, model costs by month, plan headcount, calculate cash flow, compute metrics, build three scenarios, validate assumptions and integrate fundraising. The skill also includes example projections and typical ratio ranges for SaaS, marketplace, e-commerce and services models, so the agent can compare your numbers against them.

Because the skill is a method, you should review each assumption yourself. The benchmarks are generic rules of thumb, not figures tailored to your market.

• Quick-start process: nine steps from business model to fundraising
• Retention reference: a typical SaaS curve of 100% in month 1, 75% at month 12 and 70% at month 24 (from the reference file)
• Common pitfalls to check: optimistic revenue, underestimated costs, cash timing, static headcount and single-scenario planning

What are the safety notes and limits?

The skill runs no scripts and makes no network calls, so installing it does not run code on your machine. It is still instructions that shape what the agent writes, so treat its outputs as drafts. The benchmarks and ratios are generic, and the skill is tailored to early-stage startups, not established companies with audited financials.

This skill is not a substitute for a qualified accountant or financial advisor for real investment or tax decisions.

• No scripts are run and no network access is used
• Benchmarks are generic rules of thumb; check them against your own market
• Do not rely on the output for investment or tax decisions without a qualified professional
• Verify every number the agent produces before sharing it with investors

What tips help you get better results?

Start with your actual data rather than round guesses, and state which assumptions are estimates. Ask for all three scenarios so you see the downside, not only the plan. Use the sanity checks as a review pass, and ask the agent to explain any figure that fails a check.

If you need a finished spreadsheet, ask the agent to lay out the model in a format you can paste into your own tool, since the skill itself does not create files.

• Give the agent current cash, monthly spend and retention before asking for projections
• Always ask for conservative, base and optimistic scenarios
• Ask why a metric fails a sanity check, not just whether it does
• Add a buffer to expense estimates; the skill's pitfalls section suggests 20%
• Include hiring lag: the skill notes 3-6 months to fill roles and 10-15% annual attrition