Documentation Index Fetch the complete documentation index at: https://docs.langchain.com/llms.txt
Use this file to discover all available pages before exploring further.
LangChain UI Playground Explore production-ready UI patterns for LangChain agent apps — across React , Vue , Svelte , and Angular . Pick a framework, browse demos, and open in your editor. Framework Previews Every pattern is implemented across all four frontend frameworks. Choose a tab to browse demos.
Tool Calling Render agent tool calls as rich cards — calculator, weather, search, email and more.
Human in the Loop Agent pauses and surfaces an approval card before taking a sensitive action.
Generative UI Server-driven dynamic UI — the agent emits structured component payloads rendered live.
Reasoning Tokens Collapsible chain-of-thought blocks that stream thinking tokens before the final answer.
Structured Output Agent returns typed structured data rendered with LaTeX math support.
Time Travel Branch conversation history and replay from any checkpoint using LangChain state.
Join / Rejoin Visualize fan-out/fan-in parallel subgraph execution with merge indicators.
Async Iterator Tools Stream incremental tool progress using async iterators with live progress cards.
Deep agent — Subagent Cards Hierarchical activity cards for Deep Research-style multi-subagent orchestration.
Deep agent — Todo List Agent builds and checks off a live todo list while executing a long-running task.
Deep agent — Sandbox IDE-like UI with file browser, code viewer, and diff panel backed by a sandbox environment.
Graph Execution Cards Timeline cards that visualize each LangGraph node as it executes in real time.
Markdown Messages Rich Markdown rendering with syntax-highlighted code blocks inside chat bubbles.
Message Branching Display multi-branch message threads with branch selectors inline in the chat history.
Branching Chat Full chat interface with first-class branch navigation and history traversal.
Message Queues Visualize message queue state and throughput for multi-step agent pipelines.
Subagent Streaming Stream output from multiple parallel subagents simultaneously with isolated windows.
Tool Calling Render agent tool calls as rich cards — calculator, weather, search, email and more.
Human in the Loop Agent pauses and surfaces an approval card before taking a sensitive action.
Generative UI Server-driven dynamic UI — the agent emits structured component payloads rendered live.
Reasoning Tokens Collapsible chain-of-thought blocks that stream thinking tokens before the final answer.
Structured Output Agent returns typed structured data rendered with LaTeX math support.
Time Travel Branch conversation history and replay from any checkpoint using LangChain state.
Join / Rejoin Visualize fan-out/fan-in parallel subgraph execution with merge indicators.
Async Iterator Tools Stream incremental tool progress using async iterators with live progress cards.
Deep agent — Subagent Cards Hierarchical activity cards for Deep Research-style multi-subagent orchestration.
Deep agent — Todo List Agent builds and checks off a live todo list while executing a long-running task.
Deep agent — Sandbox IDE-like UI with file browser, code viewer, and diff panel backed by a sandbox environment.
Graph Execution Cards Timeline cards that visualize each LangGraph node as it executes in real time.
Markdown Messages Rich Markdown rendering with syntax-highlighted code blocks inside chat bubbles.
Message Branching Display multi-branch message threads with branch selectors inline in the chat history.
Branching Chat Full chat interface with first-class branch navigation and history traversal.
Message Queues Visualize message queue state and throughput for multi-step agent pipelines.
Subagent Streaming Stream output from multiple parallel subagents simultaneously with isolated windows.
Tool Calling Render agent tool calls as rich cards — calculator, weather, search, email and more.
Human in the Loop Agent pauses and surfaces an approval card before taking a sensitive action.
Generative UI Server-driven dynamic UI — the agent emits structured component payloads rendered live.
Reasoning Tokens Collapsible chain-of-thought blocks that stream thinking tokens before the final answer.
Structured Output Agent returns typed structured data rendered with LaTeX math support.
Time Travel Branch conversation history and replay from any checkpoint using LangChain state.
Join / Rejoin Visualize fan-out/fan-in parallel subgraph execution with merge indicators.
Async Iterator Tools Stream incremental tool progress using async iterators with live progress cards.
Deep agent — Subagent Cards Hierarchical activity cards for Deep Research-style multi-subagent orchestration.
Deep agent — Todo List Agent builds and checks off a live todo list while executing a long-running task.
Deep agent — Sandbox IDE-like UI with file browser, code viewer, and diff panel backed by a sandbox environment.
Graph Execution Cards Timeline cards that visualize each LangGraph node as it executes in real time.
Markdown Messages Rich Markdown rendering with syntax-highlighted code blocks inside chat bubbles.
Message Branching Display multi-branch message threads with branch selectors inline in the chat history.
Branching Chat Full chat interface with first-class branch navigation and history traversal.
Message Queues Visualize message queue state and throughput for multi-step agent pipelines.
Subagent Streaming Stream output from multiple parallel subagents simultaneously with isolated windows.
Tool Calling Render agent tool calls as rich cards — calculator, weather, search, email and more.
Human in the Loop Agent pauses and surfaces an approval card before taking a sensitive action.
Generative UI Server-driven dynamic UI — the agent emits structured component payloads rendered live.
Reasoning Tokens Collapsible chain-of-thought blocks that stream thinking tokens before the final answer.
Structured Output Agent returns typed structured data rendered with LaTeX math support.
Time Travel Branch conversation history and replay from any checkpoint using LangChain state.
Join / Rejoin Visualize fan-out/fan-in parallel subgraph execution with merge indicators.
Async Iterator Tools Stream incremental tool progress using async iterators with live progress cards.
Deep agent — Subagent Cards Hierarchical activity cards for Deep Research-style multi-subagent orchestration.
Deep agent — Todo List Agent builds and checks off a live todo list while executing a long-running task.
Deep agent — Sandbox IDE-like UI with file browser, code viewer, and diff panel backed by a sandbox environment.
Graph Execution Cards Timeline cards that visualize each LangGraph node as it executes in real time.
Markdown Messages Rich Markdown rendering with syntax-highlighted code blocks inside chat bubbles.
Message Branching Display multi-branch message threads with branch selectors inline in the chat history.
Branching Chat Full chat interface with first-class branch navigation and history traversal.
Message Queues Visualize message queue state and throughput for multi-step agent pipelines.
Subagent Streaming Stream output from multiple parallel subagents simultaneously with isolated windows.
UI Framework Integrations Drop-in UI component libraries built to work with @langchain/react out of the box.
ai-elements Headless, composable React components for building AI chat UIs. Uses useStream under the hood with full shadcn/ui compatibility.
Scroll-sticky conversation container
Streaming code blocks with syntax highlighting
Collapsible reasoning / thinking blocks
Tool call display with args & results
Shimmer loading states & suggestion chips
assistant-ui A Claude-style assistant UI built with @assistant-ui/react primitives wired to LangChain via useExternalStoreRuntime.
Claude-style warm parchment theme
Chain-of-thought collapsible reasoning
Image attachment support
Copy / thumbs-up / thumbs-down action bar
Full dark mode support
OpenUI Generative UI chat where a LangChain agent emits arbitrary React components as part of the message stream — rendered live in the browser.
Agent-driven dynamic component rendering
Streaming message composition
Custom component registry
Live preview of generated interfaces
