zero vs fx
Terminal coding agents compared
zero and fx are coding agents built for terminal workflows, with interactive use and options for one-shot or scripted tasks. zero emphasizes local sessions and controls over tool actions, while fx also offers ACP integration and a WebAssembly SDK for embedding.
zero: Run a Local Terminal Coding Agent
Zero is a Go-based terminal coding agent that can inspect and edit repositories, run commands, and work with many hosted or local models. It suits developers who want scriptable coding assistance with local sessions and explicit controls over side effects.
fx: Run a Unix-Style Coding Agent in Your Terminal
fx is a native Zig coding-agent CLI with an interactive shell, one-shot requests, and embedding options. It suits developers who want an extensible, model-agnostic agent that fits terminal workflows rather than a full-screen IDE.
| zero | fx | |
|---|---|---|
| Language | Go | Zig |
| License | MIT | Apache-2.0 |
| Stars | 1.7k | 3.3k |
| Forks | 194 | 368 |
| Last analyzed | Oct 3, 2026 | Oct 4, 2026 |
Key differences
- zero is written in Go, while fx is written in Zig.
- zero uses an MIT license; fx uses Apache-2.0.
- zero provides headless `zero exec` with text, JSON, and stream-JSON I/O, while fx offers one-shot requests through `fx ask`.
- zero includes configurable permissions and sandbox policies for file writes, shell commands, network access, and additional directories; fx documents shell startup-file settings for zsh and bash.
- fx supports ACP clients and embedding through its WebAssembly SDK, while zero lists repository utilities, local sessions, and plugins among its capabilities.
- fx is described as experimental and its README advises using it at your own risk.
Choose zero if you…
- want local sessions that can be searched, resumed, forked, or rewound.
- need explicit permission and sandbox controls for agent actions.
- want headless scripting with structured input and output options.
Choose fx if you…
- want to connect through ACP-compatible clients or embed an agent using WebAssembly.
- prefer a native Zig implementation with an interactive shell and `fx ask`.
- need shell commands to reuse captured zsh or bash startup-file settings.
This comparison is generated with AI from the OSRepos analyses of both projects. Always check each project's repository and documentation before choosing.