This is my implementation of the workflow engine described in the assignment. I built it on top of FastAPI, structuring it around a simple node-based graph execution model where each node maps to a registered tool function, itself contributing to a shared workflow state. The engine supports synchronous and asynchronous tasks, including background execution for long-running steps, and exposes clear APIs for creating graphs, triggering runs, and polling their state. To start working with the project, one should activate the virtual environment, install the requirements, and start the server using Uvicorn; after this, the interactive API documentation will be available at http://127.0.0.1:8000/docs. I included two example workflows that demonstrate both sequential logic and async execution.