An open source alternative to Claude Code
AgenC Core is an open source coding agent for your terminal, like Claude Code, but MIT licensed and not tied to one model vendor. Use Claude with your Anthropic API key, or switch to DeepSeek, Grok, Gemini, OpenAI or a model on your own machine.
How they differ
| AgenC Core | Claude Code | |
|---|---|---|
| Source | Open source, MIT | Closed source |
| Models | 25 providers, Claude included | Claude only |
| Local models | Yes: Ollama, LM Studio, llama.cpp, vLLM | No |
| What you pay | Your model provider, or nothing with a local model | A Claude Pro plan or higher, or the Anthropic API |
| Headless runs | agenc -p | claude -p |
| MCP | Client and server | Client and server |
| OS sandbox | Opt-in on macOS and Linux | macOS, Linux and WSL2 |
| Terminal-Bench 2.1 | 76.2% for $34 (DeepSeek V4.1 Flash, public run) | 83.8% for $553 (Fable 5) |
Claude Code with Fable 5 scores higher. AgenC with DeepSeek scores 76.2% for about a sixteenth of that cost, and Claude Code's entries on the board cost $277 to $600 a run. All agents compared
Use Claude in AgenC
curl -fsSL https://get.agenc.ag/install.sh | sh export ANTHROPIC_API_KEY=your-key agenc --provider anthropic
AgenC uses Claude through the Anthropic API with your key. Its default Claude model is Claude Opus 5.5.
Or spend far less
export DEEPSEEK_API_KEY=your-key agenc --provider deepseek
This is the setup behind 76.2% on Terminal-Bench 2.1 for $34. AgenC with DeepSeek
Moving a project over
- AgenC reads project instructions from
AGENC.md, or fromAGENTS.mdif there is noAGENC.md. It does not readCLAUDE.md, so copy it toAGENTS.mdorAGENC.md. - The terminal UI has slash commands, approval prompts and permission modes, and
agenc -pcovers scripts and CI. Headless runs - MCP servers you already use work as they are: AgenC is an MCP client and can also serve MCP itself.
Questions
Is there an open source alternative to Claude Code?
Yes. AgenC Core is an open source coding agent for the terminal under the MIT license. It works with Claude through an Anthropic API key and with 24 other providers, including local models.
Can I use Claude models with AgenC Core?
Yes. Set ANTHROPIC_API_KEY and start agenc --provider anthropic. AgenC uses Claude through the Anthropic API with your key.
Is AgenC Core cheaper than Claude Code?
It can be. With DeepSeek V4.1 Flash, AgenC Core scored 76.2% on Terminal-Bench 2.1 for $34. Claude Code's entries on the Harbor Hub board cost $277 to $600 a run, with its top score of 83.8% from Fable 5 at $553.
Does AgenC Core read CLAUDE.md?
No. It reads AGENC.md, or AGENTS.md as a fallback. Copy your CLAUDE.md to one of those names.
Open source under the MIT license. Source code · All providers · Verify your download