#langchain

• 25 May 2026 · Study

  LangChain · LangSmith

  What LangSmith records (traces of every run, with inputs, outputs, latency and errors) and how it's enabled; locally I captured the same run tree with a callback handler, without sending anything to a hosted service.

• 13 May 2026 · Study

  LangChain · RAG

  Retrieval-augmented generation end to end with LCEL: retrieve chunks from my own notes, stuff them into a grounded prompt, answer with a local model, and return the sources with the answer.

• 6 May 2026 · Study

  LangChain · Vector stores

  Embedding chunks with a local sentence-transformer, storing them in LangChain's InMemoryVectorStore, similarity search with scores, metadata filters, and turning the store into a retriever.

• 30 Apr 2026 · Study

  LangChain · Text splitters

  Why documents are split into chunks for retrieval, how RecursiveCharacterTextSplitter tries paragraph, then sentence, then word boundaries, and what chunk size and overlap do.

• 24 Apr 2026 · Study

  LangChain · Document loaders

  The Document object (page_content + metadata), writing a small custom loader for text and CSV files, and why metadata matters later for filtering and citing sources.

• 20 Apr 2026 · Projects

  Built this: Enterprise Agentic RAG Orchestrator (Multi-Agent-RAG)

  A Supervisor → Worker → Validator multi-agent RAG system with LangGraph Corrective RAG, hybrid dense + BM25 retrieval with cross-encoder reranking, a Qdrant semantic cache and a security layer.

• 17 Apr 2026 · Study

  LangChain · Memory and message history

  Chat models are stateless; RunnableWithMessageHistory stores and re-sends past messages per session, with trimming to keep the history within limits.

• 13 Apr 2026 · Study

  LangChain · Chains and LCEL

  The LangChain Expression Language: composing Runnables with |, parallel branches, passthroughs, output parsers, and the invoke/batch/stream methods every chain inherits.

• 7 Apr 2026 · Study

  LangChain · Prompt templates

  ChatPromptTemplate for reusable prompts with variables, message placeholders for history, and few-shot examples, all producing message lists ready for any chat model.

• 1 Apr 2026 · Study

  LangChain · Chat models

  LangChain's chat-model interface: messages in, an AIMessage out, the same invoke/stream/batch methods for every provider, shown with a local Hugging Face model and a fake model for tests.

• 17 Oct 2025 · AI updates

  LangChain 1.0 released

  LangChain reached 1.0. The release notes list the final changes before it: new middleware (shell, file search, tool retry), an injectable ToolRuntime, state-schema options for create_agent, and Python 3.14 support.