Gemini CLI: Gemini 3 Flash Arrives with Frontier Agentic Performance

Gemini 3 Flash Comes to the Terminal

Gemini CLI v0.21.0 marks a significant turning point in the tool's model roster, making Gemini 3 Flash available to paid-tier users and select free-tier preview participants. While Gemini 3 Pro had already established a strong baseline for complex reasoning, Gemini 3 Flash redefines what "fast and cheap" means in an agentic coding context.

Performance That Challenges the Pro Tier

The headline number is stark: Gemini 3 Flash achieves a 78% score on SWE-bench Verified for agentic coding. That figure places it above both the entire Gemini 2.5 series and Gemini 3 Pro itself on this benchmark — a result that directly challenges the assumption that faster, cheaper models must sacrifice quality on complex software engineering tasks. Google describes the model as 3x faster than Gemini 2.5 Pro, while pricing it at less than a quarter of Gemini 3 Pro's cost per token.

Getting Access

To use Gemini 3 Flash in Gemini CLI, developers need to upgrade to version 0.21.1 or later, then enable preview features in the /settings panel. From there, running /model surfaces the Flash option alongside Gemini 3 Pro. Access at launch covers most paid-tier Gemini CLI customers.

MCP Resources Now Discoverable via @

The v0.21.0 release also adds a meaningful improvement for developers using MCP integrations. Resources — structured context objects exposed by MCP servers — can now be discovered, browsed, and searched directly from the Gemini CLI prompt using the @ command.

Hooks System and Other Improvements

Beyond Flash and MCP Resources, v0.21.0 includes a substantially expanded Hooks system. A new commands panel lets developers enable or disable hooks individually, and extension hooks now carry security warnings for third-party hook code. The update also consolidates remote MCP server configuration to use a uniform url field and introduces dynamic tool updates via the notifications/tools/list_changed protocol notification.