How-to

How to do tax prep with AI and your bank data

7 min read
Connect your business and personal banks at bankbridge.money ($5/mo per bank), then ask your agent to group last year's transactions into Schedule C categories. Useful prompts: 'What did I spend on business travel in 2026?', 'Total Q1 freelance income from Stripe', 'Export all FOOD_AND_DRINK charges for the year'. Hand the resulting CSV to your accountant or paste into TurboTax.

Who this is for

Single-member LLC owners. Freelancers filing Schedule C. 1099 contractors. Side-hustlers with a separate business account. Sole proprietors who haven't bothered with an LLC but still need to track business income and expenses.

If you're a W-2 employee taking the standard deduction with no side income, this guide is overkill. You don't need any of this. File and move on.

If you're a multi-entity S-corp with payroll, K-1s, or inventory accounting, you need a real CPA. The agent can still help with data gathering, but the filing side is too structured to DIY.

Step 1: Connect the right banks

Sign up at bankbridge.money and connect every account where business income or business expenses flow:

  • Business checking
  • Business credit card
  • Personal checking if your freelance deposits ever land there (common for sole proprietors without an LLC)
  • Personal credit cards if you ever swipe them for business expenses (and shouldn't, but reality)

$5/mo per connected bank. So a typical "business checking + business credit card at the same bank" setup is $5/mo total since they live under one institution.

Then paste your API key into whatever agent you use. Claude Desktop, Claude Code, ChatGPT, Cursor, Gemini, Codex, Continue: pick one. The connect guide is here for Claude. Each other host has a one-screen setup at /docs/<host>.

Step 2: Pull category totals

Open a new conversation with your agent. The first prompt is a wide one to give it the lay of the land:

“Group every charge on my business card and business checking for tax year 2026 into spending categories. Show me a sorted list with totals.”

The agent calls get_spending_summary grouped by category for the year. You'll get a table with things like FOOD_AND_DRINK, TRAVEL, GENERAL_SERVICES_OTHER, ENTERTAINMENT_TV_AND_MOVIES (you might want to investigate that one), and a total per category.

Now ask follow-ups that drill into the ones that matter for your Schedule C:

  • "What did I spend on business travel in 2026?"
  • "List every flight, hotel, and rideshare for the year."
  • "Show me every conference, software subscription, and domain registration that's a business deduction."
  • "Pull all meals where the merchant was a restaurant and the charge happened during a business trip."

Step 3: Export business-deductible categories

Once the categories look right, get them out of the chat. Ask:

“Render the categorized year as a CSV table I can paste into a spreadsheet. Columns: date, merchant, amount, category, Schedule C line.”

The agent generates a CSV-shaped table in the chat. Copy it, paste it into Sheets or Excel, save it. That's the artifact your accountant wants. Or, if you're filing yourself, that's what you reference while filling out Schedule C in TurboTax or FreeTaxUSA.

A useful sub-step: ask the agent to also surface anything weird.

“Any business charges this year that look unusual, duplicate, or possibly miscategorized?”

The agent will surface things like a duplicate $497 subscription that ran twice in the same month, a vendor you haven't used since March, or a charge labeled as business travel that looks suspiciously personal. Catch the edges before your accountant does.

Step 4: Estimate quarterly taxes

The single most useful tax-prep output for LLC owners and freelancers, because missing quarterly estimate payments means underpayment penalties at filing time.

“Project my full-year freelance income based on YTD trajectory. Apply a 28% effective rate (federal + state). How much should I send for the next 1040-ES?”

The agent pulls all incoming Stripe/ACH transfers tagged as business income, extrapolates to year-end, applies your rate, subtracts what you've already remitted, and gives you the quarterly number. You're responsible for the rate assumption. The arithmetic is the agent's job.

Useful starting point: 25-30% for federal plus state combined is a safe default. Refine after your first full-year filing when you have a real effective rate to plug in.

Step 5: Hand it off

At the end of a single conversation (or a few, broken across a couple of evenings), you should have:

  • Schedule C expense breakdown as a CSV table
  • Gross business income total with payor breakdown
  • Quarterly estimate calculations
  • Home-office, mileage, and meals subtotals if applicable
  • Any flagged edge cases worth manually reviewing

Email the CSV to your accountant. Or open TurboTax or FreeTaxUSA's self-employed flow and type the totals directly into the Schedule C section.

Either way, the data-gathering hours are gone. Most LLC owners spend 3-6 hours assembling this stuff manually. With the agent it's 30 minutes.

What this isn't

The agent doesn't file taxes. It doesn't know your prior-year carryforwards unless you tell it. It can't claim a deduction you don't have receipts for. It's not a CPA: don't ask it to decide whether your home office qualifies for the simplified-method deduction, ask a human for that one.

What it does: cut the data-prep hours from a full afternoon to a coffee. The savings are real, the categorization is honest, and the data lives in your bank, not in our cache. We don't store transactions.

FAQ

Will this replace TurboTax or my accountant?

No. This replaces the data-gathering step that comes before TurboTax or your accountant. Categorized totals, income sums, deductible expense breakdowns. The actual filing still needs the filing software or the tax pro.

What if my accountant wants their own categorization?

Ask the agent to output the categories your accountant requested. Most LLC accountants want a familiar layout: Advertising, Office Expenses, Travel, Meals (50%), Professional Services, Home Office, Utilities, Other. Tell the agent that's the schema you want and it'll map your transactions accordingly.

How accurate is the categorization?

About 85-90% on the first pass, depending on how clean your bank descriptors are. The agent will flag the 10-15% it isn't sure about (was that $120 Amazon purchase office supplies or a personal gift?). You decide on the edge cases, the agent does the rest.

Can the agent estimate quarterly taxes?

Yes. Give it your effective rate (rough start: 25-30% for federal plus state) and ask 'project full-year freelance income based on YTD trajectory and tell me how much to send for Q3.' The arithmetic is the agent's job. The rate assumption is yours.

What about cash transactions?

Anything paid in cash won't be in your bank data, so it won't be in the agent's view. Track cash separately (a note, a spreadsheet, even a folder of receipts you photograph). The agent handles everything that flowed through your accounts.