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fault is an Open-Source Rust-powered CLI and AI-MCP server that lets engineers and AI agents team up to ship production-ready code.

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AI-Code Generators Need Guidance

We believe software engineers experience has never been more necessary.

Lack of Operational Context

AI-Editors focus on your source code but are limited by what that they see. Operations are still out of their reach, thus leading to code that isn't always appropriate for your unique needs.

Refactoring Pain is Real

Acceleration in bootsrapping with AI-Generated code is undeniable. Yet, delivery pipelines remain time-constant as the output requires attention and refactoring before it can be pushed to production.

Safely Accelerate Your Innovation

Bring AI-generated code into your delivery pipeline with confidence.

Reliability Engineering for Developers

Explore availability threats right from the start through our builtin fault injection engine. Automate continuous validation and make sure you are respect your SLOs.

fault run
fault scenario run

AI-Agent Operational Engineering

Bring a touch of operations into your favourite AI-editor with fault builtin MCP server. Ensure you deliver production-aware code and reduce your AI-Agent delivery time.

fault agent tool
fault agent review

Modern Features for Hybrid Engineering Teams

AI is an evolution in the engineering industry journey. Not a rupture from its past.

  • Fully Open Source

    fault is open-sourced under a permissive license and part of Rebound family. Feel free to contribute to it

  • Made for Engineers

    fault is designed to work equally well with engineers and AI-agents in a team effort.

  • Choose Your LLM

    fault supports OpenAI, Gemini, OpenRouter and ollama. Pick up the LLM that best matches your working style.

  • MCP Server

    Plug fault into any AI-Code editor and help them produce sound production output with fault various tools.

  • Battery Included & Extensible

    Common network faults such as latency, blackhole or packet loss.

  • Complex Scenarios

    Easily schedule complex scenarios by configuring timelines of fault injection.

  • Support Any TCP Protocol

    While fault is well-suited for HTTP, it can be just as easily applied to any TCP-based protocol. Explore how your application reacts.

  • Observability Ready

    fault can be configured to send Open Telemetry traces to your favorite provider. Observe the effect of fault injection in your system.

  • eBPF Support

    Intercept traffic without changing anything in your application with fault's eBPF support. Turn fault injection into a stealth game.

Ready?

Download fault and build production-grade applications now.

Frequently Asked Questions

Everything you need to know about bringing fault into your organization.

What is fault?

fault is a developer product aiming at supporting engineers keep their high-standards while onboarding AI into their pipeline.

How is fault delivered?

fault is a rust-cli. It runs natively on Linux, macOSX and Windows.

Is fault free?

The fault CLI is free and open-source and will remain so. You will pay for any LLM model through your own subscription.

Do you offer enterprise commercial support?

As part of the Rebound family, we do indeed support fault commercially. Please feel free to reach out to us.

Do you upload my data anywhere?

The fault CLI doesn't send your data or code anywhere. If you use a Cloud-based LLM such as OpenAI, Gemini or Open Router, your code will be sent there partially indeed. If you want to remain fully private, we suggest you use ollama that fault also supports.

What programming language do you support?

Currently fault supports Python, Javascript, TypeScript, go and rust. More languages will likely be added.

Can I use fault without its AI features?

Absolutely. While fault provides AI-specific features, its core capabilities are not tied to AI at all. You can thus use fault to explore your reliability using the CLI directly. fault is made for all kinds of engineers!

Can I contribute to fault?

Yes! fault is open-source and love any kind of contributions. From typos to issue fixes or feature requests. Please join us.

How can we get in touch?

First, please don't hesitate. We love hearing from everyone. Just send us a message and we'll get back to you in no times.

Explore more

fault is part of the Rebound toolset of open-source projects geared towards more reliabile operations. Two other projects complete the toolbox: Chaos Toolkit - a Chaos Engineering tool - as well as Reliably - a reliability platform. Feel free to explore each of them for a comprehensive approach of your journey.