LangChain Adapter

npm install @stellartools/langchain-adapter @langchain/core

import { HumanMessage } from "@langchain/core/messages";
import { ChatOpenAI } from "@langchain/openai";
import { shield } from "@stellartools/langchain-adapter";

const model = shield(new ChatOpenAI({ model: "gpt-4o" }), {
  apiKey: process.env.STELLAR_TOOLS_API_KEY!,
  customerId: "cus_xxx",
  productId: "prod_xxx",
  cacheTTL: 120_000,
});

const result = await model.invoke([new HumanMessage("Hello")]);

import { StringOutputParser } from "@langchain/core/output_parsers";
import { ChatPromptTemplate } from "@langchain/core/prompts";

const chain = ChatPromptTemplate.fromMessages([["human", "{question}"]])
  .pipe(
    shield(new ChatOpenAI(), {
      apiKey: process.env.STELLAR_TOOLS_API_KEY!,
      customerId: "cus_xxx",
      productId: "prod_xxx",
      cacheTTL: 120_000,
    })
  )
  .pipe(new StringOutputParser());

const answer = await chain.invoke({ question: "What is Stellar?" });

import { ShieldError, shield } from "@stellartools/langchain-adapter";

try {
  const result = await model.invoke([new HumanMessage("Hello")]);
} catch (err) {
  if (err instanceof ShieldError) {
    return res.status(403).json({ error: err.message });
  }
  throw err;
}