Welcome to reflex — a small but powerful open decision model that helps you turn your current situation and questions into clear, calibrated probabilities. Whether you're a professional making strategic choices or just someone who wants to think more clearly, reflex gives you an AI-powered second opinion that's based on logic and data, not gut feeling.
Reflex is a lightweight, open-source tool that re-creates the cognitive approach of Jev / System One thinking, built on the advanced Qwen3.5 model. It takes two inputs:
The output? Calibrated probabilities — well-reasoned, percentage-based likelihoods that help you understand the odds and make more informed choices. No more vague "probably" or "maybe." Reflex gives you numbers you can actually use.
Small footprint, quick responses. Works even on modest hardware — no supercomputer needed.
Outputs precise, calibrated percentages instead of vague statements. Know your true odds.
Type your state and questions in plain language. Get structured, actionable probability estimates back.
Transparent code. No hidden algorithms or proprietary black boxes. See exactly how it works.
Follow these simple steps to get reflex running on your Windows computer:
Visit this link to download the application. This will take you to the official reflex repository page.
Look for the "Releases" section on the right side of the page, or click on the "Latest" release if shown. This is where the official Windows files are hosted.
Locate the file listed for Windows — it will typically be named something like reflex-windows.zip or reflex-setup.exe. Click it to start the download. Your browser will save the file to your Downloads folder by default.
Once the download completes, navigate to your Downloads folder and find the file you just downloaded.
reflex executable file inside.When the application opens, you'll see a simple interface with two fields. Type your current state (describe your situation), then type your questions (what you want to know). Click "Generate Probabilities" and reflex will analyze your input and provide you with calibrated probability estimates. That's it!
To get the best results from reflex, follow these tips:
If you need more help, visit the official repository and check the Issues tab. You'll find helpful guides, FAQs, and you can ask the community for assistance. The project is actively maintained, and the developers are responsive.
Reflex isn't just for one type of user. Here are some ways people use it:
For those curious about how reflex works under the hood: it's built using a state-of-the-art Qwen3.5 model fine-tuned for decision-theoretic reasoning. The system uses a "System One" approach — fast, heuristic-based reasoning that mimics human intuition but with the consistency and accuracy of AI. It's designed to be transparent, reproducible, and easy to integrate into your existing workflows.
The codebase is intentionally small and well-documented, making it a great learning resource for developers interested in decision theory and AI-assisted reasoning. All code is available for review and contribution on the repository.
Your data is yours. Reflex runs locally on your machine after the initial model download. No analytics, no tracking, no sending your state and questions to any server. We believe that a decision tool should respect your privacy completely.
Want to stay updated on the latest releases and features? Star the repository on GitHub to show your support and get notifications. You can also follow the project's release notes to see what's new.