Most apps store your data and let you search it. Cortex does something different. When you write an entry, AI reads it, understands it, and creates a structured layer on top. Later, when you ask a question, the system uses that structure to find the right entries and lets the AI interpret your original words fresh.
Here's how it works, step by step.
Step 1
You Write
You open the app and write whatever is on your mind. Text or voice. No forms, no prompts, no structure required.
This is saved as raw text on your device. Nothing leaves your phone yet.
Step 2
AI Reads and Understands
The moment you save, the AI reads your entry and extracts structured information from it:
- What type of entry is this? Are you observing your state, venting, reflecting on something, recording a strategy? The AI figures this out from what you wrote.
- What key concepts are mentioned? Terms like "fatigue," "social withdrawal," "drowsiness" are identified and normalized.
- What patterns are present? Neurodivergent patterns like social exhaustion or understimulation are detected when present.
This happens once, automatically. You don't see any of it. It runs in the background.
Step 3
Everything Stays on Your Device
Both the original text and the AI's structured understanding are stored locally on your phone. Your journal never lives on a server. The structured data sits alongside the raw text like an invisible index.
After a week, you might have 30+ entries. After a month, hundreds. Each one has been read and understood by the AI, and each one still has the original text intact.
Step 4
You Ask a Question
Days or weeks later, you open the chat and ask something.
Now the system needs to find which of your entries are relevant to this question. It can't send all of them to the AI. It needs to pick the right ones.
Step 5
The System Finds Relevant Entries
This is where the Step 2 processing pays off. The system uses the structured index to:
- Find entries that mention energy, fatigue, stimulation, or related concepts
- Filter by entry type if needed (e.g., only strategies, only observations)
- Rank results so the most relevant entries come first
Out of 30 entries this week, maybe 8 are about energy. Those 8 get selected.
Step 6
AI Reads Your Original Words
Here is the important part. The AI does not read the labels or summaries it created in Step 2. It reads your original journal text from those 8 entries. The raw words you actually wrote.
It then generates a response based on your real entries, with your real details, in your real voice.
This answer is grounded in your actual entries. Not generic advice. Not guesses. Your own data, interpreted fresh.
Why This Matters
The AI Never Reads Its Own Conclusions
The structured data from Step 2 is only used to find entries. The AI always goes back to the source text when answering.
I learned this the hard way. Early versions of Cortex fed the AI's own conclusions back into future processing. The result was a feedback loop: the AI's guesses became "confirmed patterns," which made it more confident, which produced more guesses, and so on. Confidence grew without any new information.
126 commits went into that approach before I scrapped it. The lesson: the AI is a tool for finding and interpreting. It should never be treated as a source of truth about your life. Your own words are the source of truth.
How It All Connects