start_authentication
Initiates OAuth authentication with Kroger by generating a URL for browser authorization, then requires users to copy and paste the callback URL to complete the process.
Instructions
Start the OAuth authentication flow with Kroger.
This tool returns a URL that the user needs to open in their browser
to authenticate with Kroger. After authorization, the user will be
redirected to a callback URL that they need to copy and paste back.
Returns:
Dictionary with authorization URL and instructions
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Implementation Reference
- src/kroger_mcp/tools/auth.py:28-88 (handler)Handler function for start_authentication tool. Generates PKCE parameters, builds OAuth authorization URL for Kroger API, and provides user instructions for the browser-based flow.
@mcp.tool() async def start_authentication(ctx: Context = None) -> Dict[str, Any]: """ Start the OAuth authentication flow with Kroger. This tool returns a URL that the user needs to open in their browser to authenticate with Kroger. After authorization, the user will be redirected to a callback URL that they need to copy and paste back. Returns: Dictionary with authorization URL and instructions """ global _pkce_params, _auth_state # Generate PKCE parameters _pkce_params = generate_pkce_parameters() # Generate a state parameter for CSRF protection _auth_state = _pkce_params.get('state', _pkce_params.get('code_verifier')[:16]) # Get client_id and redirect_uri from environment client_id = os.environ.get("KROGER_CLIENT_ID") redirect_uri = os.environ.get("KROGER_REDIRECT_URI", "http://localhost:8000/callback") if not client_id: if ctx: await ctx.error("Missing KROGER_CLIENT_ID environment variable") return { "error": True, "message": "Missing KROGER_CLIENT_ID environment variable. Please set up your Kroger API credentials." } # Initialize the Kroger API client kroger = KrogerAPI() # Scopes needed for Kroger API (cart.basic:write is needed for cart operations) scopes = "product.compact cart.basic:write" # Get the authorization URL with PKCE auth_url = kroger.authorization.get_authorization_url( scope=scopes, state=_auth_state, code_challenge=_pkce_params["code_challenge"], code_challenge_method=_pkce_params["code_challenge_method"] ) if ctx: await ctx.info(f"Generated auth URL with PKCE: {auth_url}") return { "auth_url": auth_url, "instructions": ( "1. Click this link to authorize: [🔗 Authorize Kroger Access]({auth_url})\n" " - Please present the authorization URL as a clickable markdown link\n" "2. Log in to your Kroger account and authorize the application\n" "3. After authorization, you'll be redirected to a callback URL\n" "4. Copy the FULL redirect URL from your browser's address bar\n" "5. Use the complete_authentication tool with that URL to complete the process" ).format(auth_url=auth_url) } - src/kroger_mcp/tools/auth_tools.py:7-10 (registration)Registers the authentication tools by delegating to auth.register_auth_tools(mcp). This is called from server.py.
def register_tools(mcp): """Register authentication tools with the FastMCP server""" register_auth_tools(mcp) - src/kroger_mcp/server.py:78-78 (registration)Site where auth_tools.register_tools is invoked during server initialization, registering the start_authentication tool.
auth_tools.register_tools(mcp) - src/kroger_mcp/tools/auth.py:25-27 (registration)Function that defines and registers both start_authentication and complete_authentication tools using @mcp.tool() decorators.
def register_auth_tools(mcp): """Register authentication-specific tools with the FastMCP server"""