LangChain Reference home page

GitHub
Main Docs

LangChain

Browser
Universal
Hub
Node
Load
Serializable
Encoder Backed
File System
In Memory
Tools

LangChain Core

Text Splitters

MCP Adapters

⌘I

Chat LangChain

What can I help with?

Enter to send·Shift+Enter new line

Menu

Browser Universal Hub Node Load Serializable Encoder Backed File System In Memory Tools

Agents Caches Base Dispatch Web Manager Promises Chat History Context Base Langsmith Documents Embeddings Errors Example Selectors Indexing Base Chat Models Compat Event Llms Openai Completions Stream Profile Stream Structured Output Load Serializable Memory Messages Tool Output Parsers Openai Functions Openai Tools Outputs Prompt Values Prompts Retrievers Document Compressors Runnables Graph Singletons Stores Structured Query Testing Tools Base Console Log Stream Run Collector Tracer Langchain Stream Async Caller Chunk Array Context Env Event Source Parse Format Function Calling Gateway Hash Json Patch Json Schema Math Ssrf Standard Schema Stream Testing Tiktoken Types Uuid Vectorstores

Language

Theme

JavaScriptlangchainbrowserContentBlock

Interface●Since v1.6

ContentBlock

LangChain Messages

Copy

interface ContentBlock

Bases

BaseContentBlock

Used in Docs

Messages
LangChain v1 migration guide

Properties

View source on GitHub

property

id: string

property

type: string

Content block identifier, which can be either

generated by the provider (e.g., a provider-specific ID)
generated by LangChain upon creation (a uuid prefixed with 'lc-')

Type of the content block