langflow-ai/langflow · error · ValueError

OAuth host and port are required to get the SSE URL for MCP

Error message

OAuth host and port are required to get the SSE URL for MCP Composer

What it means

Error "OAuth host and port are required to get the SSE URL for MCP Composer" thrown in langflow-ai/langflow.

Source

Thrown at src/backend/base/langflow/api/v1/mcp_projects.py:1224

    if not normalized_urls:
        return False

    mcp_servers = config_data.get("mcpServers", {})
    for server_name, server_config in mcp_servers.items():
        if _args_reference_urls(server_config.get("args", []), normalized_urls):
            logger.debug("Found matching server URL in server: %s", server_name)
            return True
    return False


async def get_composer_sse_url(project: Folder) -> str:
    """Get the SSE URL for a project using MCP Composer."""
    auth_config = await _get_mcp_composer_auth_config(project)
    composer_host = auth_config.get("oauth_host")
    composer_port = auth_config.get("oauth_port")
    if not composer_host or not composer_port:
        error_msg = "OAuth host and port are required to get the SSE URL for MCP Composer"
        raise ValueError(error_msg)

    composer_sse_url = f"http://{composer_host}:{composer_port}/sse"
    return await get_url_by_os(composer_host, composer_port, composer_sse_url)


async def get_config_path(client: str) -> Path:
    """Get the configuration file path for a given client and operating system."""
    os_type = platform.system()
    is_wsl = os_type == "Linux" and "microsoft" in platform.uname().release.lower()

    if client.lower() == "cursor":
        return Path.home() / ".cursor" / "mcp.json"
    if client.lower() == "windsurf":
        return Path.home() / ".codeium" / "windsurf" / "mcp_config.json"
    if client.lower() == "claude":
        if os_type == "Darwin":  # macOS
            return Path.home() / "Library" / "Application Support" / "Claude" / "claude_desktop_config.json"
        if os_type == "Windows" or is_wsl:  # Windows or WSL (Claude runs on Windows host)

View on GitHub (pinned to 976ec789d2)

Solutions

1. Set the OAuth host and port in settings before requesting the SSE URL.

When it happens

Trigger: Occurs when OAuth host and port settings are missing while computing the SSE URL for MCP Composer.

Common situations: See trigger scenarios.

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/550e4a1886abeb18. Report an issue: GitHub.