Reason is the native CLI for Reasoning Harness, an evidence-grounded AI runtime that keeps model-generated candidates separate from verified factual authority.
Publisher’s description
What is Reason?
Reason by git-ksk is open-source Windows software in the ai assistants & llms category. It is written in Rust.
Installation and requirements
The publisher provides Portable installers for 64-bit Windows. It runs without installation (portable).
Updates and version history
The current version is 0.5.5, released on October 14, 2026. The version history goes back to October 9, 2026: 3 releases, all linked to the official files. The last update is less than a month old.
Project description on GitHub: “A provider-neutral Rust harness for deterministic reasoning validation and evaluation.”
Pros / Cons
Pros
- Open source: the code can be inspected and built by anyone
- Portable: runs without installation
- Updated in the last two months
Cons
- No native ARM64 build
In short: Reason is an open-source ai assistants & llm tool for 64-bit PCs.
Is Reason safe to download?
- The file is served by github.com, the publisher’s own domain
- The download link uses HTTPS
- A SHA256 hash is published, so you can verify the file:
6C319A8C2E06E2C9B8146DB7F38C07AFB156EBE7770959F3F2CFCC1C4B15566F· Open the VirusTotal report for this hash - The link has not been checked yet
- The source code is public
- ExeAtlas does not host, wrap or modify installers
Related guide: How to check a file’s SHA256 hash on Windows
Recent versions
All 3 versions ›| Version | Date | Size | Files |
|---|---|---|---|
| 0.5.5Latest | October 14, 2026 | — | 64-bit ZIP |
| 0.5.4 | October 10, 2026 | — | 64-bit ZIP |
| 0.5.2 | October 9, 2026 | — | 64-bit ZIP |
Install from the command line
Silent install ›winget install --id git-ksk.Reason -eProgram files (.exe): reason.exe
Related guide: How to use winget: install and update apps
Information
- Publisher
- git-ksk
- Category
- AI assistants & LLMs
- Licence
- MIT
- Price
- Free
- Source code
- github.com/git-ksk/reasoning-harness
- Written in
- Rust
- Requires
- Windows 11 / 10
- Architecture
- 64-bit
- Installer
- Portable
- Version
- 0.5.5
- Released
- October 14, 2026
- Added to the catalogue
- October 9, 2026
- Versions listed
- 3
- Website
- github.com
- winget ID
- git-ksk.Reason
Ratings and reviews
No reviews yet. Be the first to rate it.
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Frequently asked questions
Is Reason free?
Yes. Reason is open-source software under the MIT licence.
Is Reason safe to download?
The download comes from github.com, which belongs to the publisher; ExeAtlas does not host or change the file. Compare its SHA256 hash with the one shown here, or open the VirusTotal report for that hash.
How do I install Reason with winget?
Open PowerShell or Windows Terminal and run the winget command shown on this page. winget downloads the official installer and checks its SHA256 hash before running it.
Does Reason run on ARM (Windows on Arm)?
There is no ARM64 build; Windows 11 on Arm can run the 64-bit version through emulation.
Where can I download an older version of Reason?
The versions page lists all 3 versions with links to their official installer files, back to October 9, 2026.
Can I use Reason without administrator rights?
Yes, it is portable: unpack and run it.
What are alternatives to Reason?
Codex CLI, Claude Code, ChatGPT, GPT4All and Jan. The alternatives page compares them.
