@composio/langchain

The LangChain provider for Composio SDK, providing seamless integration with LangChain's ecosystem and tools.

Features

- LangChain Integration: Seamless integration with LangChain's ecosystem
- LCEL Support: Full support for LangChain Expression Language (LCEL)
- Streaming Support: First-class support for streaming responses
- Tool Execution: Execute LangChain tools with proper parameter handling
- Chain Integration: Work with LangChain chains and agents
- Type Safety: Full TypeScript support with proper type definitions

Installation

``bash
npm install @composio/core @composio/langchain @langchain/core @langchain/openai


or

yarn add @composio/core @composio/langchain @langchain/core @langchain/openai

or

pnpm add @composio/core @composio/langchain @langchain/core @langchain/openai
`

Environment Variables

Required environment variables:

- COMPOSIO_API_KEY: Your Composio API key
- OPENAI_API_KEY: Your OpenAI API key (or other LLM provider's key)

Optional environment variables:

- LANGCHAIN_TRACING_V2: Enable LangChain tracing (set to "true")
- LANGCHAIN_ENDPOINT: Custom LangChain API endpoint
- LANGCHAIN_API_KEY: Your LangChain API key (for hosted services)

Quick Start

`typescript
import { Composio } from '@composio/core';
import { LangChainProvider } from '@composio/langchain';

// Initialize Composio with LangChain provider
const composio = new Composio({
apiKey: 'your-composio-api-key',
provider: new LangChainProvider(),
});

// Get available tools
const tools = await composio.tools.get('user123', {
toolkits: ['gmail', 'googlecalendar'],
limit: 10,
});

// Get tools with version control
const versionedTools = await composio.tools.get('user123', {
toolkits: ['gmail'],
toolkitVersions: { gmail: '20250909_00' },
});

// Get a specific tool
const sendEmailTool = await composio.tools.get('user123', 'GMAIL_SEND_EMAIL');
`

Examples

Check out our complete example implementations:

- Basic LangChain Integration
- LCEL Example
- RAG Example
- Streaming Example

$3

`typescript
import { Composio } from '@composio/core';
import { LangChainProvider } from '@composio/langchain';
import { ChatPromptTemplate } from '@langchain/core/prompts';
import { StringOutputParser } from '@langchain/core/output_parsers';
import { ChatOpenAI } from '@langchain/openai';

const composio = new Composio({
apiKey: process.env.COMPOSIO_API_KEY,
provider: new LangChainProvider(),
});

// Get tools for the chain
const tools = await composio.tools.get('user123', {
toolkits: ['gmail'],
limit: 10,
});

const model = new ChatOpenAI({
modelName: 'gpt-4',
streaming: true,
});

const prompt = ChatPromptTemplate.fromTemplate('Tell me a joke about {topic}');
const parser = new StringOutputParser();

const chain = prompt.pipe(model).pipe(parser);

// Stream the response
const stream = await chain.stream({
topic: 'programming',
});

for await (const chunk of stream) {
console.log(chunk);
}
`

$3

`typescript
import { Composio } from '@composio/core';
import { LangChainProvider } from '@composio/langchain';
import { ChatPromptTemplate } from '@langchain/core/prompts';
import { JsonOutputParser } from '@langchain/core/output_parsers';
import { ChatOpenAI } from '@langchain/openai';

const composio = new Composio({
apiKey: process.env.COMPOSIO_API_KEY,
provider: new LangChainProvider(),
});

// Get tools for the chain
const tools = await composio.tools.get('user123', {
toolkits: ['gmail'],
});

const model = new ChatOpenAI({
modelName: 'gpt-4',
streaming: true,
});

const chain = model.pipe(new JsonOutputParser());
const eventStream = await chain.streamEvents(
Output a list of the countries france, spain and japan and their populations in JSON format.,
{ version: 'v2' }
);

for await (const event of eventStream) {
const eventType = event.event;
if (eventType === 'on_chat_model_stream') {
console.log(Chat model chunk: ${event.data.chunk.content});
} else if (eventType === 'on_parser_stream') {
console.log(Parser chunk: ${JSON.stringify(event.data.chunk)});
}
}
`

Provider Configuration

The LangChain provider can be configured with various options:

`typescript
const provider = new LangChainProvider({
// Default model configuration
model: new ChatOpenAI({
modelName: 'gpt-4',
streaming: true,
}),
// Custom execution modifiers
modifiers: {
beforeExecute: params => {
// Transform parameters before execution
return params;
},
afterExecute: response => {
// Transform response after execution
return response;
},
},
// Enable tracing
tracing: true,
});
`

API Reference

$3

The LangChainProvider class extends BaseComposioProvider and provides LangChain-specific functionality.

#### Methods

##### executeToolCall(tool: Tool): Promise

Executes a LangChain tool call and returns the result.

`typescript
const result = await provider.executeToolCall(tool);
``

Contributing

We welcome contributions! Please see our Contributing Guide for more details.

License

ISC License

Support

For support, please visit our Documentation or join our Discord Community.