I looked at the most relevant coding harnesses that run locally on your machine.
These are the six serious options right now:
- Claude Code: Best Claude harness, but proprietary and without a free tier.
- OpenAI Codex: Open-source OpenAI agent for CLI and VS Code.
- Gemini CLI: Best free fallback, with up to 1,000 requests per day.
- OpenCode: Best independent open-source option with BYOK and local models.
- Cursor: Mature proprietary AI-first IDE with a free plan.
- Devin Desktop: Formerly Windsurf, with multiple models and a limited free tier.
My classification:
- Primary tools: Claude Code and Codex
- Best fallbacks: Gemini CLI and OpenCode
My fallback stack would therefore be:
Claude Code and Codex for daily work. Gemini CLI and OpenCode when I hit a usage limit.
One important distinction: a free harness does not necessarily include free model usage. Gemini CLI currently offers the most attractive clearly documented free allowance.