A personal budget in one evening: bank statement + AI

Here's the header of my bank statement — the first 8 rows, including
column names. This is already anonymized data.

[paste 8 rows]

Tell me what's in this file:
1. What each column means, and which one is the amount, the date,
   and the counterparty name.
2. What the delimiter is, what the encoding is, and how decimals
   and thousands are written.
3. How to tell an expense from income in this format.
4. Which columns are useless for budgeting and can be deleted.
5. What's missing from this export for it to work as a budget
   (e.g. a missing payment type or empty descriptions).

Don't calculate anything yet, just describe the structure.

Write me a Python script that prepares my bank statement for
further processing. The script will run locally on my machine.

Input: file statement.csv, delimiter semicolon, encoding
[UTF-8 / Windows-1252], decimal comma, amounts with a negative
value for expenses.
Columns: [list the column names].

The script should:
1. Load the file and convert amounts to numbers (handle thousands
   separators and decimal commas).
2. Delete these columns: [account numbers, reference number, address].
3. In the counterparty name, replace these strings with a generic
   description: [list, e.g. employer's name -> "salary"].
4. Add a "month" column in YYYY-MM format.
5. Flag rows where the counterparty is one of my own accounts
   [list of identifiers] with the value "internal transfer".
6. Save the result as statement-anon.csv in UTF-8.

Write a comment for each step explaining what it does.
The script must handle empty cells without breaking.

I'm attaching an anonymized bank statement covering [12] months
(columns: date, amount, payment type, description, month).

Sort every transaction into one of these categories:
[housing, food - groceries, food - restaurants, food - delivery,
transportation, subscriptions and services, health, clothing,
entertainment, gifts, one-off big expenses, loan payments and
savings, other]

Rules:
- Don't count rows flagged as internal transfers at all — just
  list them separately at the end.
- Don't categorize income as an expense; put it in its own group
  and separate regular income from irregular income.
- If you're not sure about a payment, DON'T GUESS. Put it in an
  "uncategorized" group and list it separately.
- Flag one-off expenses over [5,000] on their own, even if they
  belong to another category.

Give me:
1. A table: category, total for the whole period, monthly average,
   number of transactions, share of total expenses.
2. The "uncategorized" list with date, amount, and description.
3. The ten largest individual expenses for the period.

Based on how you just sorted my transactions, build me a mapping
table of rules that I'll use every month.

Format: keyword or pattern in the description | category | note

Conditions:
- Base it only on payments that actually appeared in my statement.
- Use the most general patterns possible (a chain's name, not a
  specific branch), so the rule still holds next time.
- For each rule, note how many transactions it would cover in my
  annual statement.
- List separately any payments that recur but don't map well to
  a rule, and explain why.
- Sort the rules from most common to least.

At the end, tell me what share of my transactions this rule set
would cover automatically.

Build me a monthly summary for the whole period from the sorted
transactions.

For each month, calculate:
- total income (regular and irregular, separately),
- total expenses,
- expenses broken down by category,
- cash flow = income minus expenses,
- cash flow WITHOUT one-off big expenses (so I can see what my
  normal month-to-month spending looks like).

Don't include transfers between my own accounts in the calculation.

Then write me a summary:
1. How many months had negative cash flow, and which ones.
2. What my average monthly baseline spending is (median expenses,
   not the mean — and explain why they differ in my case).
3. The three categories that swing the most between months.
4. Which months are consistently the most expensive for me, and why.

For every number, say how many transactions it's built from.
Don't give me recommendations, just the numbers and description.

Go through my annual statement and find all recurring payments.

Treat a payment as recurring if it went to the same or a very
similar counterparty at least [3] times over the period, in a
similar amount, at a regular interval.

For each one, give me:
- the counterparty description,
- the typical amount and whether it changed during the year (if
  so, when and by how much),
- the cadence (monthly, quarterly, yearly),
- how many times it occurred over the period,
- the total for the period and the annualized total,
- the date of the last payment.

List three groups separately:
A) payments that look like digital-service subscriptions,
B) recurring payments that aren't subscriptions (rent, insurance,
   loan payments, savings),
C) yearly or twice-yearly payments that only occurred once or
   twice over the year.

At the end, give me the total: how much group A costs me per year,
and how much all recurring payments together cost.

Take my group A list of recurring payments and turn it into a
decision table I can go through.

Columns:
service | monthly | annually | last paid | question to ask myself |
what to check before canceling

In the question column, write a specific question for that service,
not a generic phrase — e.g. "when did I last open this" for
entertainment, or "do I already have this in another service" for
overlapping subscriptions.

In the last column, write what I should verify before canceling
anything: whether something else depends on it, whether it's an
annual payment I've already paid for this year, whether the service
has stored content on it.

Sort by most expensive annually. Don't recommend canceling anything
yourself — just prepare the questions, I decide.

Design me the structure of a budget spreadsheet for Google Sheets
that I'll update every month.

I want three sheets:
1. "transactions" — this is where I paste the bank export. Columns:
   date, month, amount, payment type, description, category, note.
2. "summary" — a monthly summary: rows are categories, columns are
   months, cells hold the totals. Below the table, rows for: total
   income, total expenses, cash flow, cash flow without one-off
   expenses.
3. "categories" — a list of my categories and the mapping rules.

Tell me specifically:
- what formulas to put in the "summary" sheet so the totals
  calculate themselves by category and month (include which cell
  each one goes in),
- how to set up a category dropdown list in the "transactions"
  sheet,
- how to color-code months with negative cash flow,
- how to make sure the formulas don't break when new rows get
  added.

Assume I'm a beginner: write it as a step-by-step process.

Design me a personal budget database in Notion.

Describe:
- what properties the transactions database should have and of
  what type (date, number, select, formula, relation),
- how to set up a property that automatically turns the date into
  a month, so I can group by it,
- what views I should create: current month, category comparison,
  recurring payments only, uncategorized transactions only,
- how to set up a cash flow summary for a selected month,
- what page template to use for the monthly close-out, and what
  checklist should be on it.

Write it as a process I can click through, not as theory.
Don't assume I already know Notion formulas.

This is my monthly budget prompt. I'm attaching an anonymized
statement for [month] and my mapping rule table.

1. Sort the transactions using the attached rules. Anything that
   doesn't match a rule goes into "uncategorized," listed out —
   don't guess.
2. Calculate for this month: income, expenses by category, cash
   flow, and cash flow without one-off expenses.
3. Compare against previous months, which I'm attaching as a
   summary:
   - categories that grew or shrank by more than [20]%,
   - new recurring payments that didn't appear before,
   - recurring payments that are missing this month,
   - payments that stand out from my usual pattern.
4. Give me a three-sentence summary: what changed this month.

Don't give me savings advice. I want facts and deviations.

I'm attaching my monthly budget summaries for [period]. I'm
interested in the trend, not individual months.

Evaluate:
1. Which categories are growing long-term and which are shrinking —
   for each, give the percentage change between the first and last
   month, and whether the change is gradual or sudden.
2. Seasonality: which months are consistently the most expensive,
   and why (which categories are responsible).
3. Cash flow trend: how many months were negative, whether the
   situation is improving or getting worse, and the sum of cash
   flow over the whole period.
4. The share of fixed (recurring) expenses out of the total — and
   how that share is changing.
5. How much I'd need monthly to cover just the expenses I can't
   cancel quickly.

For every conclusion, state which numbers it's based on. Where the
period is too short for a conclusion, say so instead of guessing.

Build me an artifact: a simple page showing an overview of my
budget. I'll give you the data as monthly summaries, attached.

I want it to have:
1. A bar chart of cash flow by month — positive and negative
   months color-coded, with a zero line.
2. A chart showing the trend of three categories I pick from a
   dropdown (pull the data from my summary).
3. A row of key numbers at the top: average monthly expenses
   (median), share of fixed expenses, number of negative months.
4. A table below the charts, sortable by category and amount.

Labels in English, amounts with a thousands separator.
No advice or judgment, just a display of my data.
Make sure it works on mobile too.