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Comparisons4 min read

Claude Code alternatives: nine coding agents, and why you might not have to choose

Codex, OpenCode, Kimi Code, DeepSeek Harness, Qwen Code and four more coding agents, grouped by why you'd switch, and how to run them next to Claude Code.

Mirasim's agent picker open in a session: Claude Code, Kimi Code, DSH, Pi, Antigravity, Qwen Code, ZCode and Grok BuildMirasim's agent picker open in a session: Claude Code, Kimi Code, DSH, Pi, Antigravity, Qwen Code, ZCode and Grok Build

The short answer

If you want another company's models, pick the agent that company makes: Codex for OpenAI, Kimi Code for Moonshot AI, DeepSeek Harness for DeepSeek, Antigravity for Google, Grok Build for xAI. If you want open source with any provider, look at OpenCode. Mirasim runs all of them next to Claude Code, so trying one doesn't mean giving the other up.

Codex
You already pay for ChatGPT
OpenCode
You want open source and to bring any provider's models
DeepSeek Harness, Kimi Code
You want DeepSeek's or Moonshot's models, or to work in Chinese
Run them side by side in Mirasim
You don't want to choose

Which agent writes the best code changes with every model release; the most reliable test is giving two of them the same task on your own repository.

Agents made by the model companies

Codex (OpenAI)
OpenAI's coding agent. The CLI is open source under Apache-2.0. Sign in with ChatGPT Plus, Pro, Business, Edu or Enterprise, or use an API key.
Kimi Code (Moonshot AI)
An MIT-licensed terminal agent that runs the Kimi models. Sign in with Kimi Code OAuth or a Kimi platform API key.
DeepSeek Harness (DeepSeek)
DeepSeek's MIT-licensed agent harness, in developer preview, running the DeepSeek V4 models. Signs in with a DeepSeek API key.
Qwen Code (Alibaba)
Alibaba's open-source coding agent, built for the Qwen3-Coder models.
Antigravity (Google)
Google's agent CLI, running the Gemini models, with browser and subagent tools.
Grok Build (xAI)
xAI's coding agent, running the Grok models your account can use.

Article · Claude Code vs Codex: how they differ, and using both → Claude Code and Codex compared side by side.

Agents that run any provider's models

OpenCode
An open-source coding agent that uses the providers you set up in it, and comes with free models that need no sign-in.
ZCode
A CLI agent that runs GLM models or a model provider you configure.
Pi
A minimal terminal agent with four tools and a short system prompt, running the models you add.

Article · Pi coding agent in Mirasim: the minimal harness, next to your other agents → Pi on its own: install, providers, and running it in Mirasim.

Use them next to Claude Code instead

One Mirasim windowClaude Code plus any of these nine, each in its own pane
  • Same task, two agentsCompare their changes before you decide
  • Hand over mid-taskSwitch a session to another agent and keep the conversation
  • Try without signing upKimi Code and DeepSeek Harness can run on Mirasim credit
  • Your own accountsEach agent keeps its own sign-in; Mirasim runs the version you installed
Agent Config installs the ones you don't have yet and shows each one's installed and latest version.

Article · Run Claude Code, Codex, OpenCode and seven more coding agents in one app → All ten agents in one app, and what that adds.

Questions

Is Mirasim a Claude Code alternative?
No. Mirasim is a desktop app that runs Claude Code and the agents on this page, so you can use several of them together and share sessions with other people.
Which Claude Code alternative is open source?
Codex's CLI (Apache-2.0), Kimi Code (MIT), DeepSeek Harness (MIT), OpenCode and Qwen Code.
Can I try one without a new subscription?
OpenCode comes with free models that need no sign-in. In Mirasim, Kimi Code and DeepSeek Harness can also run on Mirasim credit.
Can I keep my CLAUDE.md?
Codex reads AGENTS.md, and Claude Code can read an AGENTS.md in place of a CLAUDE.md, so moving your rules to AGENTS.md lets both use them.

Sources

Checked on November 8, 2026 against github.com/openai/codex, github.com/MoonshotAI/kimi-code, deepseek.com/en/harness and code.claude.com/docs/en/overview. The other agents' descriptions come from Mirasim's own documentation of the agents it runs. All of them change quickly, so check each project's page for the latest.

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