GC-201a · Module 2

The Extensions Ecosystem

3 min read

Extensions are community-built packages that bundle tools, commands, and configuration into installable units. Each extension has a gemini-extension.json manifest declaring its capabilities. The Extensions Gallery at geminicli.com is the discovery hub. Install with gemini extensions install name, remove with gemini extensions remove name. Extensions can provide MCP servers, custom commands, GEMINI.md context, and specialized tools — all bundled into a single install step.

The Google ecosystem extensions deserve priority attention. Firebase (deploy, manage, query Firestore), Cloud Run (container deployment), BigQuery (query execution and schema exploration), Google Workspace (Docs, Sheets, Drive), and Data Commons (public datasets). These are maintained by Google engineers and integrate seamlessly with Google Cloud credentials. If your stack touches Google services, these extensions are not optional — they are essential.

# Install core Google ecosystem extensions
gemini extensions install firebase
gemini extensions install cloud-run
gemini extensions install bigquery

# List what you have installed
gemini extensions list

# Check what tools an extension provides
/tools
# Filter for extension-provided tools

Do This

  • Check the Extensions Gallery before building custom MCP servers
  • Install Google ecosystem extensions if your stack uses Google Cloud
  • Audit installed extensions quarterly — remove unused ones to save context

Avoid This

  • Build a custom MCP server for Firebase when the official extension exists
  • Install every interesting extension and leave them all active permanently
  • Forget that extensions consume context tokens even when you are not using their tools