Developers often struggle with brittle, monolithic code that's hard to test and rearrange. A new tutorial builds a minimal Executable Chain abstraction from scratch to demonstrate the power of composable logic. This approach breaks down complex workflows into small, focused units, mirroring patterns seen in frameworks like LangChain but without the framework's complexity.

The core design centers on an Executable interface where each step takes input, performs work, and returns a ChainAction to control flow. A ChainContext object passes state between steps using a simple key-value map, trading type safety for flexibility. The Chain class orchestrates the entire sequence, running steps until a STOP action is triggered or the chain completes.

Using an order processing example, the tutorial shows how to validate, check inventory, reserve stock, take payment, and send notifications as discrete steps. This separation makes the system more predictable and easier to modify. While the implementation lacks advanced features like parallel execution or rollback, it provides a clear mental model for understanding how modern workflow engines and AI pipelines actually work under the hood.