Coding agents: Add full-stack auth to your app

Install the authstack plugin, then tell your coding agent to add SaaSKit auth to your app.

Claude Code

1. Install the authstack plugin

   Terminal

   npx @scalekit-inc/cli setup

   For repeated use, install globally:

   Terminal

   npm install -g @scalekit-inc/cli
   scalekit setup

   Select Claude Code when prompted. The CLI installs the authstack plugin for you.

   Tool-native alternative (if not using the CLI)

   claude plugin marketplace add scalekit-inc/authstack
   claude plugin install agentkit@authstack
   claude plugin install saaskit@authstack

   Or run /plugins inside Claude to enable via the wizard.

2. Generate authentication implementation

   Copy the following prompt into your coding agent:

   Authentication implementation prompt

   Add SaaSKit auth to my app. I need login, sessions, and logout.

   Review generated code

   Always review AI-generated authentication code before deployment. Verify that environment variables, token validation logic, and error handling match your security requirements. The coding agent provides a foundation, but you must ensure it aligns with your application’s specific needs.

3. Verify the implementation

   After the coding agent completes, verify that all authentication components are properly configured:

   Check generated files:

   • Scalekit client initialization with environment credentials (you may need to set up a .env file with your Scalekit API credentials)
   • Login route that redirects to Scalekit’s authorization endpoint
   • OAuth callback route that exchanges the code for tokens
   • Secure session storage with proper cookie attributes
   • Logout endpoint that clears the session

   The login flow should redirect users to Scalekit’s authorization page, where they authenticate. Your application should then exchange the returned authorization code for tokens, store the session, and redirect the user to the protected area of your app.

Codex

1. Install the authstack plugin (recommended)

   Terminal

   npx @scalekit-inc/cli setup

   For repeated use, install globally:

   Terminal

   npm install -g @scalekit-inc/cli
   scalekit setup

   Choose Codex when prompted. The CLI installs the authstack plugin.

2. Enable the SaaSKit plugin

   Restart Codex and enable the authstack plugin in the Plugin Directory.

3. Generate the authentication implementation

   Copy the following prompt into Codex:

   Authentication implementation prompt

   Add SaaSKit auth to my app. I need login, sessions, and logout.

   Codex loads the SaaSKit plugin from the authstack plugin, analyzes your existing application structure, generates Scalekit client initialization with environment credentials, creates the login redirect handler, implements the OAuth callback to exchange the authorization code for tokens, and adds secure session storage with a logout endpoint.

   Review generated code

   Always review AI-generated authentication code before deployment. Verify that environment variables, token validation logic, and error handling match your security requirements. The coding agent provides a foundation, but you must ensure it aligns with your application’s specific needs.

4. Verify the implementation

   After Codex completes, verify that all authentication components are properly configured:

   Check generated files:

   • Scalekit client initialization with environment credentials. You may need to set up a .env file with your Scalekit API credentials.
   • Login route that redirects to Scalekit’s authorization endpoint
   • OAuth callback route that exchanges the code for tokens
   • Secure session storage with proper cookie attributes
   • Logout endpoint that clears session state

   The login flow should redirect users to Scalekit’s authorization page, where they authenticate. Your application should then exchange the returned authorization code for tokens, store the session, and redirect the user to the protected area of your app.

When you connect, users authenticate through the OAuth 2.0 flow you configured. Verify that protected routes require a valid session and that the logout endpoint properly clears session state.

GitHub Copilot CLI

1. Install the authstack plugin (recommended)

   Terminal

   npx @scalekit-inc/cli setup

   For repeated use, install globally:

   Terminal

   npm install -g @scalekit-inc/cli
   scalekit setup

   The CLI installs the authstack plugin for GitHub Copilot.

   Tool-native alternative

   copilot plugin marketplace add scalekit-inc/authstack
   copilot plugin install agentkit@authstack
   copilot plugin install saaskit@authstack

   Use copilot plugin list to verify.

2. Generate authentication implementation

   Copy the following command into your terminal:

   Terminal

   copilot "Add SaaSKit auth to my app. I need login, sessions, and logout."

   GitHub Copilot uses the SaaSKit plugin to analyze your existing application structure, generate Scalekit client initialization code, create the login redirect handler, implement the OAuth callback for token exchange, add secure session storage, and provide a logout endpoint.

   Review generated code

   Always review AI-generated authentication code before deployment. Verify that environment variables, token validation logic, and error handling match your security requirements. The coding agent provides a foundation, but you must ensure it aligns with your application’s specific needs.

3. Verify the implementation

   After GitHub Copilot completes, verify that all authentication components are properly configured:

   Check generated files:

   • Scalekit client initialization with environment credentials (you may need to set up a .env file with your Scalekit API credentials)
   • Login route that redirects to Scalekit’s authorization endpoint
   • OAuth callback route that exchanges the code for tokens
   • Secure session storage with proper cookie attributes
   • Logout endpoint that clears the session

   The login flow should redirect users to Scalekit’s authorization page, where they authenticate. Your application should then exchange the returned authorization code for tokens, store the session, and redirect the user to the protected area of your app.

When you connect, users authenticate through the OAuth 2.0 flow you configured. Verify that protected routes require a valid session and that the logout endpoint properly clears session state.

Cursor

1. Install the authstack plugin (recommended)

   Terminal

   npx @scalekit-inc/cli setup

   For repeated use, install globally:

   Terminal

   npm install -g @scalekit-inc/cli
   scalekit setup

   The CLI detects Cursor and installs the authstack plugin directly.

2. Reload and select plugins

   Restart Cursor (or run Developer: Reload Window), then open Settings > Cursor Settings > Plugins.

   Enable the Scalekit plugins you need (AgentKit, SaaSKit, etc.).

   Alternative for other agents

   For 40+ agents (Windsurf, Cline, etc.) or to install skills manually, the CLI also offers the skills option, or run:

   npx skills add scalekit-inc/authstack

3. Generate the implementation

   Open Cursor’s chat panel with Cmd+L (macOS) or Ctrl+L (Windows/Linux) and paste in an implementation prompt from the feature page (or describe what you need in natural language). The installed Scalekit plugins provide the agent with accurate patterns.

   Review generated code

   Always review AI-generated authentication code before deployment. Verify that environment variables, token validation logic, and error handling match your application’s security requirements.

4. Verify the implementation

   After Cursor finishes generating code, confirm all authentication components are in place:

   • The Scalekit plugin appears in Settings > Cursor Settings > Plugins
   • Scalekit client initialized with your API credentials (set up a .env file with your Scalekit environment variables)
   • Authorization URL generation and callback handler
   • Session or token integration matching your application’s existing patterns

40+ agents

The authstack plugin works with 40+ AI agents. Skills are installed via the Scalekit CLI or the Vercel Skills CLI.

The easiest way for most developers is:

Terminal

npx @scalekit-inc/cli setup

For repeated use, install globally:

Terminal

npm install -g @scalekit-inc/cli
scalekit setup

Then choose the “Other agents” / skills option when prompted.

You can also install the skills directly:

1. Install interactively

   Run the command with no flags to be guided through the available skills:

   Terminal

   npx skills add scalekit-inc/authstack

2. Browse and install a specific skill

   Install the skill for your auth type (for example, MCP OAuth):

   Terminal

   # List all available skills
   npx skills add scalekit-inc/authstack --list
   
   # Install a specific skill
   npx skills add scalekit-inc/authstack --skill adding-mcp-oauth

3. Invoke the skill Varies by agent

   Each coding agent has its own behavior for invoking skills. In OpenCode, skills are invoked automatically by the agent based on natural language — no slash commands required. The agent has a list of available skills and their description fields in context. It reads your intent, matches it against those descriptions, and autonomously calls the skill tool to load the relevant SKILL.md. A clear, specific description in skill frontmatter is what the agent uses to decide which skill to invoke.

   Flow in practice:

   • You write a natural language message to the agent
   • The agent checks its context — it already sees <available_skills> with names and descriptions
   • If your request matches a skill’s purpose, the agent calls skill("<name>") internally
   • The full SKILL.md content loads into context and the agent follows those instructions

   If your agent does not automatically pick up skills, you can run a command to load a skill and manually select Scalekit’s skills to load into context. Refer to your favorite coding agent’s documentation for how to invoke skills once they are installed.

4. Install all skills globally

   To add all Scalekit authentication skills to your agents:

   Terminal

   npx skills add scalekit-inc/authstack --all --global

   This installs all AgentKit and SaaSKit skills.