Databricks MCP Proxy

Instructions

Implementation Reference

• src/databricks_mcp_proxy/server.py:61-82 (handler)

  The handler function implementing the list_databricks_tools tool. It lists all discovered remote tools with their names, descriptions, and input parameters if available. Requires prior authentication.

  @mcp.tool()
  def list_databricks_tools() -> str:
      """
      List all available tools on the remote Databricks MCP server.
      Must authenticate first.
      """
      if not state.authenticated or not state.proxy:
          return "Not authenticated. Call 'authenticate' first."
      
      if not state.proxy.tools:
          return "No tools available."
      
      lines = [f"Available tools ({len(state.proxy.tools)}):\n"]
      for tool in state.proxy.tools:
          lines.append(f"**{tool.name}**")
          lines.append(f"  {tool.description}")
          if tool.input_schema.get("properties"):
              lines.append(f"  Parameters: {list(tool.input_schema['properties'].keys())}")
          lines.append("")
      
      return "\n".join(lines)

• src/databricks_mcp_proxy/server.py:28-59 (helper)

  The authenticate tool handler which initializes the proxy, connects, and calls discover_tools to populate the list of remote tools used by list_databricks_tools.

  @mcp.tool()
  def authenticate() -> str:
      """
      Authenticate with Databricks using OAuth U2M flow.
      Opens a browser for authorization.
      Uses DATABRICKS_HOST and DATABRICKS_APP_URL from app.yaml or environment.
      """
      try:
          host = state.host or os.environ.get("DATABRICKS_HOST")
          app_url = state.app_url or os.environ.get("DATABRICKS_APP_URL")
          scopes = state.scopes or os.environ.get("DATABRICKS_SCOPES", DEFAULT_SCOPES)
          
          if not host:
              return "Error: DATABRICKS_HOST not configured. Set it in app.yaml or environment."
          if not app_url:
              return "Error: DATABRICKS_APP_URL not configured. Set it in app.yaml or environment."
          
          print(f"Starting OAuth flow for {host}...", file=sys.stderr)
          access_token = start_oauth_flow(host, scopes)
          
          state.proxy = DatabricksMCPProxy(host, app_url, access_token)
          state.proxy.connect()
          state.proxy.discover_tools()
          state.authenticated = True
          
          tool_names = [t.name for t in state.proxy.tools]
          return f"Authenticated successfully!\n\nAvailable tools ({len(tool_names)}):\n" + "\n".join(f"  - {name}" for name in tool_names)
      
      except Exception as e:
          state.authenticated = False
          return f"Authentication failed: {e}"

• src/databricks_mcp_proxy/server.py:61-82 (registration)

  The @mcp.tool() decorator registers the list_databricks_tools function with the FastMCP server instance.

  @mcp.tool()
  def list_databricks_tools() -> str:
      """
      List all available tools on the remote Databricks MCP server.
      Must authenticate first.
      """
      if not state.authenticated or not state.proxy:
          return "Not authenticated. Call 'authenticate' first."
      
      if not state.proxy.tools:
          return "No tools available."
      
      lines = [f"Available tools ({len(state.proxy.tools)}):\n"]
      for tool in state.proxy.tools:
          lines.append(f"**{tool.name}**")
          lines.append(f"  {tool.description}")
          if tool.input_schema.get("properties"):
              lines.append(f"  Parameters: {list(tool.input_schema['properties'].keys())}")
          lines.append("")
      
      return "\n".join(lines)