LANGCHAIN-AGENTS
LangChain Agents agentic LLMs tool use ReAct.
Définition
LangChain Agents key concepts : (1) Agents : LLM-powered components that decide actions via Reasoning (chain-of-thought) + Acting (tool calls), iterate until completion or max iterations. (2) Tools : functions exposed to LLM (search engines DuckDuckGo + Google, calculator, custom Python functions wrapped as Tool, REST APIs, SQL databases, vector DBs, etc.), tool description Markdown LLM understands. (3) Agent types : ReAct Agent (most common, Reasoning + Acting iterative), Plan-and-Execute Agent (Planner + Executor LLMs separate), Conversational Agent (chat history aware), OpenAI Functions Agent (uses OpenAI function calling), Tool Calling Agent (modern, supports any LLM with tool calling capability). (4) AgentExecutor : runtime that orchestrates agent + tools, handles max_iterations, max_execution_time, error handling. (5) Memory : ConversationBufferMemory, ConversationSummaryMemory, etc. retain context across iterations. (6) LangGraph (since 2024) : alternative to AgentExecutor, builds agentic workflows as graph (nodes = functions, edges = transitions), more control + visibility. Integration : LangSmith (observability + tracing + evals), LangServe (deploy LangChain apps via FastAPI), LangGraph Cloud (managed graph workflows). LangChain library Python + JavaScript, ~12000+ contributors 2024.
Origine
LangChain initial release octobre 2022 par Harrison Chase (ex-Robust Intelligence) ; LangChain Inc. fondee 2023 ; Series A $25M April 2023 (Sequoia Capital + Benchmark) ; Series B negotiation 2024 ; ~80000+ GitHub stars 2024.
Exemple en contexte
Customer service AI assistant uses LangChain Tool Calling Agent : tools available = search company knowledge base, query CRM customer record, escalate to human ; user 'mon order #12345 not arrived', agent reasons + calls CRM Tool (gets shipping info delayed) + calls Knowledge Base Tool (gets policy refund) + responds 'your order was shipped 5 days ago, expected today, here is tracking link + apologies if delayed'.
Termes liés
- LangGraph — evolution graph-based.