A decision journal you can look back on, with dates
By The Architect team · Last updated
We make Architect (formerly The Architect). What this page says about the app and The Billionaire was checked against the app itself on October 29, 2026.
A decision journal is where you write down a decision when you make it, with your reasons, so you can look back later at what you actually thought. Architect is a private journal that keeps each entry with its date and notes the decisions in it, and its mentor The Billionaire pushes on the reasoning before you commit. When the same decision comes round again, it can bring back what you wrote, word for word, with the date.
Free to start, no card. What you write is encrypted on your device, the key stays with you, and it is never used to train AI.
How to keep a decision journal here
- Write the decision the day you make it. What you decided, why, what you expect to happen, and how sure you are. Plain sentences; there is no form to fill.
- Let The Billionaire argue with it. It gives the counterargument first, works out its own numbers, and says how sure it is. It asks things like "What is the actual constraint here?" and "Are you optimizing for the right variable?"
- Write what happened. When the result comes in, write it down. If it echoes the earlier entry, the mentor can set the old line beside it, with its date.
- Look back. History holds every entry. On the paid plan, Ask The Architect answers questions from your whole journal, such as what did I decide about hiring, and why?
What it remembers, and when
Architect remembers what you wrote, and when. After a reply, it keeps dated notes on what the entry recorded, such as a decision, a commitment, a belief or a turning point, along with lines copied from your own words. They are encrypted with the same key as your journal.
That is what makes a decision journal worth keeping: not what you remember deciding, but what you wrote at the time. When a reply quotes an earlier entry and the quote is matched to your words, it appears in a gold card with its date, copied from your entry, not reworded, and a tap opens the original page.
What it sounds like
You, on March 3: "No new hires until revenue covers two salaries."
You: "Decided to hire a second engineer. It feels right this time."
The Billionaire: "On March 3 you wrote, 'No new hires until revenue covers two salaries.' Today's entry says nothing about revenue. I'd put moderate confidence on this being the March decision made again with a different feeling. Tell me what changed."
You: "Revenue hasn't moved. But we're drowning in support."
The Billionaire: "That's new evidence, and it counts. March priced the hire in revenue; today you're paying for it in hours. I'd put moderate confidence on one variable deciding this: what the hours you buy back would let you do that pays for the hire. Write your answer down today, and the call is yours."
The March line in a reply like this is the person's own entry, with its date; the mentor quotes an earlier entry only when there is one to quote.
Honest limits
- It is a journal, not a form. There are no outcome fields, scores or review reminders. You write the decision and the result in your own words.
- It does not reread every page for every reply. Each reply reads today's entries first, then a selection of recent ones, and older entries come back through the dated notes when they fit what you are writing now. It can miss one; say so in the conversation.
- Your record is yours. Export your whole journal to a file, free on every plan. Entries can be up to 25,000 characters.
Free and paid
The Billionaire is on every plan. Choose it in Settings, Your mentor, or switch to it in the middle of a conversation. Writing is free, and every entry saves. The free plan includes 11 full mentor replies, then one reply every 7 days. No card is needed.
The paid plan is $33 a month, $299 a year, or $9.99 a week. It adds replies with no daily cap, Ask The Architect (up to 10 questions a day, answered from your whole journal) and Insights. Every number is on the pricing page. For the mentors, see the AI mentor app page; for the whole app, what Architect is.