ctx is now open-source, a hackable desktop workbench for coding agents

Hi HN, we posted here back in April and the most common request was to make the source code public.

As of today, ctx is now open-source: https://github.com/ctxrs/ctx

ctx is an Agentic Development Environment (ADE), similar to the Codex desktop app, but it works with any agent harness.

We wrote more about why we are open sourcing it here: https://ctx.rs/blog/open-sourcing-ctx

A few things contributed to the decision to do this:

- We fell in love with Pi's extensibility model. In late 2025, we were forking Codex to add and change behaviors, but even small changes required deep surgery and rebuilding. Lately, we've been able to make those same changes with Pi, but it's so much easier. It feels closer to configuring a tool rather than rebuilding its internals. Everything seems to "just work" as an extension/plugin. We realized we wanted our ADE to work like that too. You should be able to have a sensible default desktop app, and then powerful customization options to change how it looks and works.

- The AI ecosystem is rapidly coalescing into a state-adjacent oligopoly. Today, SpaceX announced it will acquire Cursor, and last week the US government shut down Fable/Mythos. This trend is not new, but it has been accelerating lately. It makes the case for an open agent tooling ecosystem much more compelling.

- We realized we cannot build the one perfect ADE for everyone. No amount of predetermined customization options can support the near-infinite creativity that is possible through open source code. This is especially true when everyone has a coding agent that can quickly implement customization on the fly. Maybe this is "Software 3.0" finally starting to show itself.

From here, the roadmap is to make ctx more hackable. Right now it is a fairly involved Rust daemon plus desktop app. It's performant, but customization still requires cloning the repo, changing code, and rebuilding. We want to move toward a Pi-like model with extensions, plugins, and hot-reloading, while keeping the core runtime in Rust.

We'd also like to accelerate development of the mobile app (via a bring-your-own tunnel like ngrok, or hosted tunnel) as well as support for Windows (it is Mac and Linux only right now).