We propose a symbolic generative task description language and inference engine, capable of representing arbitrary multimodal tasks as symbolic flows.The inference engine maps natural language instructions to symbolic flow, eliminating the need for task-specific training.Conventional generative models rely heavily on large-scale training and implicit neural representation to learn cross-modal mappings, which demands extensive computational resources and restricts expandability. In this paper, we propose an explicit symbolic task descriptive language, comprising three types of primitives: functions, parameters, and topological logic. Using a pre-trained language model to infer symbolic workflows in a training-free manner, our framework successfully performs over 12 multimodal generative tasks based on user instructions, demonstrating enhanced efficiency and flexibility. Extensive experiments demonstrate that our approach can generate multimodal content competitive with, and often surpassing, that of previous state-of-the-art unified models, while offering robust interruptibility and editability. We believe that symbolic task representations are capable of cost-effectively expanding the boundaries of generative AI capabilities. All code and results are available in the Supplementary Materials.