Family Tree with AI — what works and where AI makes up relatives

Myth × truth

What the viral video promises, step by step

Four requests to the chat and a promise of citizenship. See what holds up and why.

Myth vs. fact, prompts that work, where to research, how to verify each name, DNA testing, and citizenship

Promise	Does it work?	Why
1. "Ask me everything and build my initial family tree"	✅ Yes	AI only organizes what you told it. There's nothing to make up.
2. "Tell the story of my family line based on my surname"	⚠️ Half-truth	The origin of the surname is generic. Having the same last name doesn’t mean you’re in the same family.
3. "Research records and find relatives I don’t know about"	❌ Makes things up	Good databases require a login or are paid, and many records (in Brazil and across Latin America) aren’t indexed online. With common names, AI mixes up people with the same name and fills in the gaps with plausible people. "Names you’ve never heard of" are exactly the danger.
4. "Build the complete visual family tree"	✅ Draws	But the diagram doesn’t make the names from step 3 true.
+ "You’re going to find a citizenship"	❌ Exaggeration	Citizenship is proven with certificates. And the rules have gotten stricter: Italy limited citizenship by descent in 2025 (Law 74/2025), and Portugal changed its nationality law in 2025–2026, with parts challenged in the Constitutional Court. Information verified in November 2026: confirm with the consulate.

AI isn’t the detective. It’s your assistant. The document is what confirms it.

🧠 Why it makes things up

A language model writes the most likely text, not the most truthful. Without finding the record, the “likely” answer is a list of names that look real.

📄 Where it shines

Organize what you know, read old handwriting, translate Latin and Italian from records, suggest where to look, and put together a list of documents.

🧬 Truly unknown relatives

Only a genealogy DNA test can find cousins you don't know without starting from a document. AI can't do that.

Step by step · 8 prompts

Copy, paste, and replace what’s between < >

The prompts are also in the folder prompts/ from the repository. They all follow the same rule: without proof, it doesn't go in.

The files in the prompts/ and docs/ folders are in Portuguese; every prompt and every list is translated on this page.

Family interview

Start with living relatives. AI asks the questions and prepares a guide for you to talk with your oldest relative.

I want to build my family tree, starting with what my relatives and I know. 1) Ask me questions ONE AT A TIME: my full name, date and place of birth, and the same for my parents, grandparents, and great-grandparents. Also ask about nicknames, occupation, religion, where they came from, and when they arrived in this country. 2) Then put together a list of 15 questions for me to ask my oldest relative. 3) Rule: DO NOT add any person, date, or place that I haven’t mentioned. When something is missing, write "I don’t know" and say which document could confirm it.

Organize it in a table

Everything becomes a table with a source column and a status column. It’s the one the script draws in step 8.

Based on everything I’ve told you, create a CSV table with these columns, in this order: id,name,birth,place_of_birth,father_id,mother_id,source,status,note - Put any value that contains a comma in double quotes ("Joinville, SC"). - Short, unique id (p01, p02...). father_id and mother_id use these ids. - source = link to the record or the document. Leave blank if there isn’t one. - status = CONFIRMED only if the source is filled in; otherwise HYPOTHESIS. - A relative’s story ("grandma told me") is not a source: it stays HYPOTHESIS. - note = what’s missing for confirmation. Don’t make anyone up. Respond with only the CSV.

CSV is a text table with columns separated by commas. To save it: copy the response, paste it into Notepad (Windows) or TextEdit in plain text mode (Mac), and save it as my-family.csv inside the project folder. Or paste it into Google Sheets and download it as .csv. In Notepad, under "Save as type", choose "All files" (otherwise it becomes .csv.txt), and leave out the ``` lines if the chat adds them (the script ignores them too). The script accepts commas or semicolons.

Read an old document (photo)

AI is excellent at this: difficult handwriting, Latin, Italian, German. You verify it against the image.

This is a photo of an old record from my family. 1) Transcribe it exactly as written, line by line. Where you can’t read it, write [illegible] — don’t guess. 2) Translate it into English. 3) List: names, dates, places, parents, godparents/witnesses, occupation, and the book/page/entry number. Mark every uncertain reading with (?).

Where to look

AI suggests archives and registry offices. Open each link before you trust it.

My great-grandfather <NAME>, born around <YEAR> in <CITY, COUNTRY>, arrived in <COUNTRY> around <YEAR> and lived in <CITY, STATE>. List where to look for his records, in order of likelihood of success: online collections (OFFICIAL link and exact collection name), likely civil registry offices or parishes, immigration archives. For each one: type of record, whether it’s free, and whether it has name search or images only. If you’re not sure a collection exists, say “I’m not sure.”

Research backed by evidence (the prompt that stops hallucinations)

The safe version of "find relatives I don’t know about." Use it in a chat that can browse the web: in the ChatGPT app, tap the + next to the text box and choose web search (or agent mode, if your plan includes it). Button names change between app versions.

Search public records for <FULL NAME>, born around <YEAR> in <PLACE>, child of <FATHER> and <MOTHER>. REQUIRED RULES: 1) Only include someone under CONFIRMED if you opened a record with NAME + DATE + PLACE, and give me the DIRECT LINK to the record and the collection name. 2) Say which information in the record connects the person to my family (parents, spouse, address). A matching last name is NOT a connection. 3) Put assumptions on a separate list, HYPOTHESES, with the reason and the document that would confirm them. 4) If you find nothing, answer "I couldn't find anything." I prefer that to an invented name. 5) Don't fill in dates or places that aren't in the record.

Auditing an answer you already got

Already have a list that AI “found”? Open a new chat (without the history) and ask for an audit.

Below is a list of relatives that an AI chat said it found in "public records." I do NOT trust it. For each person: say whether there’s a verifiable source (direct link, collection, book/page); classify as SOURCE TO CHECK or NO SOURCE (likely made up); point out inconsistencies (ages, dates, places, people with the same name). Don’t add or confirm anyone without a source. <paste the list here>

Citizenship: the document checklist

AI organizes the process; the law and the consulate make the decision. Ask for the date of the information. The prompt terms (full-text certificate, Hague Apostille, sworn translation) are in the glossary.

My ancestor <NAME>, born in <YEAR> in <CITY, COUNTRY>, is my <great-grandfather/grandfather>. The line down to me is: <he> → <child> → <grandchild> → me. 1) List the certificates normally requested to prove this line, for each generation, and where each one comes from. 2) Tell me which ones usually need a full-text certificate, a Hague Apostille, and a sworn translation. 3) Explain, with the DATE of your information, what I need to verify in the current law of <COUNTRY>, and give me the official consulate website link. 4) Don’t tell me I “have a right”; tell me what I need to verify.

Visual tree with confirmed people only

Open a terminal in the project folder: on Windows, open the folder in File Explorer, click the address bar, type powershell and press Enter; on Mac, right-click the folder → Services → New Terminal at Folder; on Linux, right-click → Open in terminal. Then run the script with the table from step 2. It also checks that anyone marked CONFIRMED without a source (or with only the website address) becomes a hypothesis, and flags impossible ages for a father or mother. The script reads the English columns from step 2 and answers in English.

# Mac and Linux
python3 scripts/arvore.py my-family.csv --output my-tree.html   # saves my-tree.html
python3 scripts/arvore.py my-family.csv --only-confirmed --output only-proof.html
python3 scripts/arvore.py modelos/people.csv --output example.html   # fictional example family
# Windows (PowerShell)
py scripts\arvore.py my-family.csv --output my-tree.html
py scripts\arvore.py my-family.csv --only-confirmed --output only-proof.html
py scripts\arvore.py modelos\people.csv --output example.html

The script only saves the file: double-click my-tree.html in the folder to open it in your browser (it needs an internet connection to render). No computer? Ask the chat: "draw this table in Mermaid, HYPOTHESIS with a dashed border, without adding anyone" and paste the result into mermaid.live to see the drawing. To move the tree to a genealogy website, the standard format is GEDCOM (.ged): build the tree directly on FamilySearch or MyHeritage, or ask the chat to convert the table to GEDCOM and import it on the site.

Where to really research

The archives AI won’t access for you

Start at home: certificates, work records, passports, letters, and photos with notes on the back. Then check these archives.

Where	What it has	Cost
FamilySearch (familysearch.org)	Civil and parish records from several states in Brazil and around the world. Many are only available as images, with no name search, so you have to browse through them.	Free
Civil registry office (Brazil: cartório)	The full-text certificate (inteiro teor, a faithful copy of the book) is the one that counts for citizenship. Request it at the registry office or online.	Paid
Parishes and diocesan offices	Baptisms, marriages, and deaths from before civil registration became widespread.	Varies
State archives and the National Archives (Brazil)	Immigration, naturalization, probate records. The National Archives holds passenger lists for ships that arrived in Rio.	Free
Museu da Imigração (São Paulo, Brazil)	Records of the immigrant hostel (Hospedaria de Imigrantes) and passenger lists.	Free
United States: NARA, Ellis Island passenger search, state vital records offices	National Archives (census, naturalization, ship lists), the Statue of Liberty–Ellis Island Foundation passenger database (arrivals in New York), and each state’s vital records office for birth, marriage and death certificates.	Mostly free
Your country’s civil registry and national archive	The list above is strongest for Brazil. In any country, the civil registry and the national archive hold births, marriages, deaths and immigration. Ask the chat for your country’s list with prompt 4 and open every link.	Varies
Hemeroteca Digital (Brazil’s National Library)	Old newspapers: marriages, deaths, ship arrivals.	Free
Antenati Portal (Italy)	Civil records from Italian state archives.	Free
Digitarq (Portugal)	Digitized parish records from district archives.	Free
Matricula (Germany, Austria, Poland)	Catholic parish registers.	Free
Szukaj w Archiwach and Geneteka (Poland)	Digitized Polish state archives and a volunteer-built index of parish and civil records.	Free
DNA test (MyHeritage, Ancestry, and others)	Compare your DNA with that of other people who have been tested and find real cousins. Each company compares results against its own database; some sites accept DNA files from another company (upload), which broadens the search. DNA is sensitive data: read the privacy policy.	Paid

Glossary

The tricky words, in one line

So no one gets stuck along the way.

Hallucination

When AI makes something up that looks real: a name, a date, a record that doesn’t exist.

Person with the same name

A different person with the same name. The biggest risk in genealogy: finding the wrong "José Rossi."

Indexed

A record you can find by typing in a name. Not indexed = only a photo of the book, so you have to browse page by page.

Parish record

A baptism, marriage, or death recorded in the church book. Before civil registry offices, it was the main record.

Full-text certificate

A certificate that copies the complete record from the registry office book, including parents, grandparents, and notes. It’s the one that counts for citizenship.

Hague Apostille

A certificate added by an authorized office that makes a document from one country valid in another (in Brazil, a notary; in the US, the Secretary of State of the state that issued the document).

Sworn translation

Official translation, done by a registered public translator, required for citizenship applications.

CSV

Table saved as text, with columns separated by commas. Opens in Excel and Google Sheets.

Mermaid and GEDCOM

Mermaid is a language that turns text into a diagram. GEDCOM (.ged) is the standard file format for moving a family tree from one genealogy site to another.

Your family tree with AI, with no made-up relatives