About CodeMantis

A native macOS app that turns Claude Code and OpenAI Codex from terminal tools into a full development environment.

The Story

CodeMantis was born out of a simple frustration: Claude Code is incredibly powerful, but living inside a terminal makes it harder to use than it needs to be. Switching between windows, losing context, copying file paths — it all adds up. We wanted something that felt native, fast, and purpose-built for the way people actually work with AI coding assistants.

So we built it. A real macOS app — not an Electron wrapper, not a web view — a Tauri-powered native application that gives Claude Code — and, as of v1.3.0, OpenAI Codex — the interface they deserve.

What Makes It Different

CodeMantis wraps Claude Code and Codex in a three-panel layout: your chat, your files, and your terminal — all in one window. No tab switching, no split screens, no context lost. Everything you need is right there.

Beyond the layout, CodeMantis brings features that a terminal simply cannot offer: a visual spec writer that turns ideas into structured prompts, project templates, multi-session support so you can run several AI agents in parallel, a live activity feed, and a built-in file viewer with syntax highlighting.

Built to Outlast Any One Vendor

On June 15, 2026, Anthropic restructured Claude subscription billing — Agent SDK and claude -p(programmatic mode) moved to a separate, metered credit pool, while interactive Claude Code stayed on the original subscription. CodeMantis runs the user's own claudebinary, which keeps us in the explicitly-permitted lane. But the change made the principle clear: any app that depends on a single vendor's policy decisions is one memo away from breaking its users.

We had already shipped an AgentAdapterabstraction in v1.2.0, ostensibly for clean code. It turned out to be the seatbelt we didn't know we'd need. v1.3.0 added OpenAI Codex as a first-class second agent. v1.5.0 added per-task routing — write specs with Claude, run hot main chat on Codex, or whatever balance fits your subscription pool. The next agent CLI is a config away, not a rewrite.

Read the full reasoning in our blog post: Why CodeMantis Now Supports Two Coding Agents (and Soon More).

Free and Open Source

CodeMantis is completely free and released under the MIT License. No subscriptions, no paywalls, no usage limits. The entire source code is available on GitHub. We believe developer tools should be open — you can inspect the code, contribute features, or fork it and make it your own.

Built for Creators

CodeMantis is built for the people AI coding was made for: innovators, founders, and domain experts who have ideas worth building but have never shipped code before. The app handles the complexity so they can focus on what matters — turning ideas into working software.

To learn more about the vision behind CodeMantis, read about its creator: Meet Harald.

Get in Touch

We would love to hear from you — whether it is a feature request, a bug report, or just to say hello.