LangChain.js

npm install @veriproof/sdk-core @veriproof/sdk-instrumentation-langchainjs @langchain/core @langchain/anthropic

VERIPROOF_API_KEY=vp_live_...
VERIPROOF_APPLICATION_ID=my-langchain-app
ANTHROPIC_API_KEY=sk-ant-...

import { configureVeriproof, VeriproofSdkOptions, VeriproofSession,
         SessionIntent, RiskLevel, StepOutcome, StepType } from '@veriproof/sdk-core';
import { VeriproofLangChainJSInstrumentation } from '@veriproof/sdk-instrumentation-langchainjs';
import { ChatAnthropic } from '@langchain/anthropic';
import { ChatPromptTemplate } from '@langchain/core/prompts';
import { StringOutputParser } from '@langchain/core/output_parsers';
 
// 1. Configure VeriProof with the LangChain instrumentation adapter
const { provider } = configureVeriproof(
  VeriproofSdkOptions.createDevelopment({
    apiKey: process.env.VERIPROOF_API_KEY!,
    applicationId: process.env.VERIPROOF_APPLICATION_ID!,
  }),
  {
    serviceName: process.env.VERIPROOF_APPLICATION_ID!,
    setGlobal: true,
    instrumentations: [new VeriproofLangChainJSInstrumentation()],
  },
);
process.on('SIGTERM', async () => { await provider.shutdown(); });
 
// 2. Build a governance session
const session = new VeriproofSession({
  applicationId: process.env.VERIPROOF_APPLICATION_ID!,
  sessionName: 'contract-summarisation',
  intent: SessionIntent.ANALYSIS,
});
 
await session.addStep({
  stepName: 'summarise-contract',
  stepType: StepType.ANALYSIS,
  input: { documentId: 'contract:C-2026-0042', pageCount: 18 },
});
 
// 3. Build and invoke a LangChain chain — all spans captured automatically
const model = new ChatAnthropic({ model: 'claude-3-5-haiku-20241022', maxTokens: 512 });
const prompt = ChatPromptTemplate.fromMessages([
  ['system', 'You are a legal analyst. Summarise the key obligations of each party.'],
  ['human', '{contract_text}'],
]);
const chain = prompt.pipe(model).pipe(new StringOutputParser());
 
const summary = await chain.invoke({
  contract_text: '...contract text here...',
});
 
// 4. Record outcome and complete
await session.setDecision({
  decisionSummary: summary,
  riskLevel: RiskLevel.LOW,
  outcome: StepOutcome.COMPLETED,
});
 
const result = await session.complete();
console.log('Session ID:', result.sessionId);