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Firebase Basics

GoogleOfficialPublished by Google

  • Skill
  • Tool integration
  • Cloud and DevOps
  • Apache-2.0
  • Low risk
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From the author

Provides foundational Firebase CLI setup, CLI installation, version checks (`firebase-tools@latest --version`), CLI login (including --no-localhost), project creation, project selection (`firebase use`), and app config file downloads (`google-services.json`, `GoogleService-Info.plist`). Use ONLY for CLI login, project creation/switching, or downloading app config files. Don't use for Firebase Hosting deploy, Firestore, Auth, App Hosting, Data Connect, Crashlytics, or Remote Config.
— the description by Google

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

The firebase-basics skill provides a standardized approach for initializing and managing the Firebase CLI environment. It enforces best practices such as using npx for command execution to ensure version consistency and provides structured workflows for authentication, project selection, and programmatic retrieval of platform-specific configuration files like google-services.json and GoogleService-Info.plist. This skill serves as a prerequisite for more advanced Firebase operations.

What it does

  • Verifies and checks the version of the Firebase CLI.
  • Handles user authentication via the CLI, including support for headless environments.
  • Manages Firebase project selection and context switching.
  • Facilitates the creation of new Firebase projects.
  • Automates the retrieval of Android and iOS configuration files.

When to use it

  • When setting up a new development environment for a Firebase-backed project.
  • When you need to authenticate with Firebase services via the CLI.
  • When switching between different Firebase projects.
  • When you need to download project-specific configuration files for mobile apps.

Advantages

  • Ensures consistent CLI usage by mandating npx for all commands.
  • Provides clear, standardized procedures for project initialization.
  • Reduces manual effort by automating the download of configuration files.
  • Includes specific guidance for headless or remote server environments.

Usage examples

“Log me into Firebase.”
The agent executes the login command using npx, providing the --no-localhost flag if the environment is detected as a remote shell.
“I need to set my active project to my-app-123.”
The agent verifies the current project context and executes the command to switch to the specified project ID.
“Download the google-services.json for my Android app.”
The agent uses the Firebase CLI to fetch the SDK configuration for the specified Android app ID and saves it to the correct project path.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/google/firebase-basics/download

  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip firebase-basics.zip -d .agents/skills

Documentation by Google

Firebase Basics

Usage Attribution

MUST READ: Before executing any gcloud, REST API, or MCP command, you MUST read and follow the instructions in Usage Attribution.

Prerequisites

Complete these setup steps before proceeding:

  1. Local Environment Setup: Verify the environment is properly set up so we can use Firebase tools:

  2. Authentication: Ensure you are logged in to Firebase so that commands have the correct permissions. Run npx -y firebase-tools@latest login. For environments without a browser (e.g., remote shells), use npx -y firebase-tools@latest login --no-localhost.

    • The command should output the current user.

    • If you are not logged in, follow the interactive instructions from this command to authenticate.

  3. Active Project: Most Firebase tasks require an active project context.

    [!IMPORTANT] For Agents: Before proceeding with project configuration, you MUST pause and ask the developer if they prefer to:

    1. Provide an existing Firebase Project ID, or

    2. Create a new Firebase project.

    • If using an existing Project ID:

      1. Check the current project by running npx -y firebase-tools@latest use.

      2. If the command outputs Active Project: <project-id>, confirm with the user if this is the intended project.

      3. If not, or if no project is active, set the project provided by the user:

      npx -y firebase-tools@latest use <PROJECT_ID>

    • If creating a new project: Run the following command to create it:

      npx -y firebase-tools@latest projects:create <project-id> --display-name "<display-name>"

      Note: The <project-id> must be 6-30 characters, lowercase, and can contain digits and hyphens. It must be globally unique.

Firebase Usage Principles

Adhere to these principles:

  1. Use npx for CLI commands: To ensure you always use the latest version of the Firebase CLI, always prepend commands with npx -y firebase-tools@latest instead of just firebase. For example, use npx -y firebase-tools@latest --version. NEVER suggest the naked firebase command as an alternative.

  2. Prioritize official knowledge: For any Firebase-related knowledge, consult the developerknowledge_search_documents MCP tool before falling back to Google Search or your internal knowledge base. Including "Firebase" in your search query significantly improves relevance.

  3. Follow Agent Skills for implementation guidance: Skills provide opinionated workflows (CUJs), security rules, and best practices. Always consult them to understand how to implement Firebase features correctly instead of relying on general knowledge.

  4. Use Firebase MCP Server tools instead of direct API calls: Whenever you need to interact with remote Firebase APIs (such as fetching Crashlytics logs or executing Data Connect queries), use the tools provided by the Firebase MCP Server instead of attempting manual API calls.

  5. Keep Plugin / Agent Skills updated: Since Firebase best practices evolve quickly, regularly check for and install updates to their Firebase plugin or Agent Skills. Similarly, if you encounter issues with outdated tools or commands, follow the steps below based on your agent environment:

  6. Automate Config File Retrieval: When setting up iOS or Android apps, do NOT direct users to the Firebase Console to download google-services.json or GoogleService-Info.plist. Instead, use the Firebase CLI to fetch the config programmatically:

    • For Android: npx -y firebase-tools@latest apps:sdkconfig ANDROID <APP_ID> --project <PROJECT_ID>

    • For iOS: npx -y firebase-tools@latest apps:sdkconfig IOS <APP_ID> --project <PROJECT_ID> Save the output to the appropriate location (e.g., app/google-services.json for Android, or a path to be linked by xcode-project-setup for iOS).

References

Common Issues

  • Login Issues: If the browser fails to open during the login step, use npx -y firebase-tools@latest login --no-localhost instead.

  • Genkit: If using Genkit, install the skills:

    npx skills add genkit-ai/skills

Files

references/ios_setup.md

Firebase iOS Setup Guide

⛔️ CRITICAL RULE: STATE MANAGEMENT (OBSERVATION VS COMBINE) ⛔️

When writing or updating SwiftUI code, you MUST prioritize the modern Swift Observation framework (@Observable macro and @State) as your default approach.

However, it is acceptable to use Combine (ObservableObject, @Published, @StateObject, @EnvironmentObject) under the following conditions:

  • The user explicitly asks you to use Combine.

  • There are strong signals in the existing codebase that the project is heavily relying on Combine.

If neither of those conditions are true, default to the Swift 5.9+ Observation framework.

⛔️ CRITICAL RULE: INITIALIZATION ORDER ⛔️

When using SwiftUI, you MUST ensure FirebaseApp.configure() is called BEFORE any Firebase-dependent state objects are initialized.

  • UNSAFE (CRASH): Declaring a @State (for @Observable) or @StateObject (for Combine) property in the root App struct if its initializer touches Firebase. Property initializers run before the App.init() body, meaning the object's init() will fire before Firebase is configured.

  • SAFE: Initialize Firebase in App.init() and pass your state objects into the sub-views (like ContentView), or use onAppear for delayed setup.

Failing to follow this will result in a fatal crash: Default FirebaseApp is not configured.

1. Create a Firebase Project and App (Automated)

Do not use the Firebase Console. Use the CLI to automate setup:

  1. Create the project: npx -y firebase-tools@latest projects:create

  2. Action: Read the Xcode project (.pbxproj or Info.plist) to determine the iOS bundle ID.

  3. Register the iOS app: npx -y firebase-tools@latest apps:create IOS <bundle-id>

  4. Fetch the config: npx -y firebase-tools@latest apps:sdkconfig IOS <App-ID>

  5. Save the output as GoogleService-Info.plist in your Xcode project folder. Ensure you remove any non-XML CLI output headers, and ensure the file is linked to the main application target.

2. Installation (Automated via Swift Package Manager CLI)

Do not use raw text parsing, sed, or Ruby scripts (like xcodeproj gem) to modify .pbxproj files directly.

Instead, use the xcode-project-setup skill. Load that skill using your tools to securely execute its native Swift package setup script. That skill handles installing the required SPM packages and safely linking the GoogleService-Info.plist file.

💡 TIP: ALWAYS USE THE LATEST SDK VERSION To ensure access to the latest features and security fixes, always check for the most recent version of the Firebase iOS SDK at https://github.com/firebase/firebase-ios-sdk/releases and use that version when adding the SPM dependency.

3. Initialization

Configure the shared FirebaseApp instance. You can do this either in a modern SwiftUI App structure or a traditional AppDelegate.

SwiftUI (Modern - SAFE PATTERN)
import SwiftUI
import FirebaseCore

@main
struct YourApp: App {
  // ⛔️ FATAL CRASH: @State private var auth = AuthManager()
  // property initializers run before init(), causing FirebaseApp not configured error
  @State private var authManager: AuthManager

  init() {
    // ✅ SAFE: This runs FIRST
    FirebaseApp.configure()

    // ✅ SAFE: Initialize state ONLY AFTER Firebase is configured
    _authManager = State(initialValue: AuthManager())
  }

  var body: some Scene {
    WindowGroup {
      ContentView()
        .environment(authManager)
    }
  }
}
AppDelegate (Traditional / UIKit)
import UIKit
import FirebaseCore

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
  func application(_ application: UIApplication,
                   didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
    // ✅ SAFE: Always the first line in didFinishLaunching
    FirebaseApp.configure()
    return true
  }
}

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Node.js

Security

What our scanner noticed· Low risk

  • Instructions that use the network

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
Google
Publisher
Google (Official)
Source
google/skills · skills/cloud/firebase-basics · commit 2194d3b
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
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Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download firebase-basics.zip