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

LangChain Assistant

Ask a question to get started

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 Hash Json Patch Json Schema Math Ssrf Standard Schema Stream Testing Tiktoken Types Uuid Vectorstores

Language

Theme

JavaScript@langchain/coretestingStreamUsageExpectation

Type●Since v1.2

StreamUsageExpectation

Copy

StreamUsageExpectation

Properties

View source on GitHub

property

input_token_details: Record<string, unknown>

property

input_tokens: number

property

output_token_details: Record<string, unknown>

property

output_tokens: number

property

total_tokens: number

Breakdown of input token counts.

Does not need to sum to full input token count. Does not need to have all keys.

Count of input (or prompt) tokens. Sum of all input token types.

Breakdown of output token counts.

Does not need to sum to full output token count. Does not need to have all keys.

Count of output (or completion) tokens. Sum of all output token types.