[LangChain](https://www.langchain.com/) is a framework that eases developing with LLMs. # Vocabulary - Chain - Model - Prompt - Output parser - **Prompt template** - Similar to a Mustache template. Replace prompt variables with user values at run time. - **LCEL** - LangChain Expression Language - Uses pipe syntax, i.e., `|` - **Runnable** protocol - stream - invoke - batch # Features - [Force models to call a tool](https://python.langchain.com/docs/how_to/tool_choice/) - [OpenTelemetry support](https://changelog.langchain.com/announcements/end-to-end-native-opentelemetry-support-for-langsmith-sdk) for metrics/analytics # Alternatives - AutoGPT - GPT-Engineer - LlamaIndex - Microsoft AutoGen # Contact - Slack - [Join](https://www.langchain.com/join-community) the channel - [Visit](https://app.slack.com/client/T05P4BNF01J/C05NZ3SMWTF) the channel - Email: [email protected] # Resources - https://chat.langchain.com/?threadId=8b948dfc-7b41-4ce0-8fbd-7dc387aa5fd0 - https://docs.smith.langchain.com/evaluation/how_to_guides/attach_user_feedback - Lucas Soares taught *Getting started with LangChain* on O'Reilly ## Traces - [Tag traces with metadata | LangChain](https://docs.smith.langchain.com/observability/how_to_guides/add_metadata_tags) - [Log user feedback | LangChain](https://docs.smith.langchain.com/evaluation/how_to_guides/attach_user_feedback) - [View threads | LangChain](https://docs.langchain.com/langsmith/threads#view-threads) # Testing - [Vitest and Jest | LangChain](https://docs.langchain.com/langsmith/vitest-jest) - [Pytest | LangChain](https://docs.langchain.com/langsmith/pytest) - [Simulate a conversation | GitHub](https://github.com/langchain-ai/openevals?tab=readme-ov-file#multiturn-simulation) ## Evals - openevals: https://github.com/langchain-ai/openevals - agentevals: https://github.com/langchain-ai/agentevals