LangChain & LLMs b7 2024
Learning and Mastering LangChain
A practical mental model for LangChain: chains, tools, memory, and how to avoid building fragile LLM spaghetti.
LangChain can feel overwhelming if you treat it as a framework you must fully adopt. I treat it as a toolbox: a set of helpers to wire together LLM calls, tools, and memory in a way that is testable and debuggable.
Chains as explicit workflows
I start by writing down the exact steps an ideal human expert would follow to answer a request. Then I encode those steps as a chain: retrieve context, call tools, format intermediate state, and only then call the model. This approach avoids the "single giant prompt" anti-pattern.
Tools and guards
Tools are where LangChain becomes interesting: database lookups, HTTP calls, calculators, custom business logic. I design tools with strict, typed inputs and clear error messages so I can log and monitor how often they fail. The LLM is then orchestrating reliable pieces instead of improvising everything.