Google announced its open-source Gemini-CLI that brings natural language command execution directly to developer terminals. Beyond natural language, it brings the power of Google’s Gemini Pro 2.5 — and it does it mostly for free. The free tier provides 60 model requests per minute and 1,000 requests per day at no charge, limits that Google deliberately set above typical developer usage patterns. The tool is open source under the Apache 2.0 license. While Gemini CLI is mostly free, OpenAI and Anthropic’s tools are not. Google senior staff software engineer Taylor Mullen noted that many users will not use OpenAI Codex or Claude code for just any task, as it carries a cost. Another key differentiator for Gemini CLI lies in its extensibility architecture, built around the emerging Model Context Protocol (MCP) standard. This approach lets developers connect external services and add new capabilities and positions the tool as a platform rather than a single-purpose application. The extensibility model includes three layers: Built-in MCP server support, bundled extensions that combine MCP servers with configuration files and custom Gemini.md files for project-specific customization. This architecture allows individual developers to tailor their experience while enabling teams to standardize workflows across projects. If an organization wants to run multiple Gemini CLI agents in parallel, or if there are specific policy, governance or data residency requirements, a paid API key comes in. The key could be for access to Google Vertex AI, which provides commercial access to a series of models including, but not limited to, Gemini Pro 2.5. Gemini CLI operates as a local agent with built-in security measures that address common concerns about AI command execution. The system requires explicit user confirmation for each command, with options to “allow once,” “always allow” or deny specific operations. The tool’s security model includes multiple layers of protection. Users can use native macOS Seatbelt support for sandboxing, run the agent in Docker or Podman containers, and route all network traffic through proxies for inspection. The open-source nature under Apache 2.0 licensing allows complete code auditing.