@nest-langchain/anthropic

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Anthropic chat model provider for NestJS dependency injection.

This package wires a ChatAnthropic instance from @langchain/anthropic into NestJS dependency injection. Connection info (apiKey, optional anthropicApiUrl) lives at the module level; model and temperature are chosen per preset or per call via a factory — the library no longer picks a default model.

Install

pnpm add @nest-langchain/anthropic @langchain/anthropic

Module

import { Module } from '@nestjs/common';
import { AnthropicProviderModule } from '@nest-langchain/anthropic';

@Module({
  imports: [
    AnthropicProviderModule.forRoot({
      apiKey: process.env.ANTHROPIC_API_KEY,
      presets: [
        { name: 'haiku', model: 'claude-haiku-4-5-20251001', temperature: 0 },
        { name: 'sonnet', model: 'claude-sonnet-4-5', temperature: 0.4 },
      ],
    }),
  ],
})
export class AiModule {}

Environment fallbacks for apiKey: ANTHROPIC_API_KEY, CLAUDE_API_KEY. ANTHROPIC_BASE_URL (or the baseUrl / anthropicApiUrl option) sets a compatible endpoint.

Injection

Inject a named preset, or inject the factory for per-call model creation. model is always required — the library never assumes one:

import { Injectable } from '@nestjs/common';
import { ChatAnthropic } from '@langchain/anthropic';
import {
  InjectAnthropicChatModel,
  InjectAnthropicChatModelFactory,
  AnthropicChatModelFactory,
} from '@nest-langchain/anthropic';

@Injectable()
export class ReviewService {
  constructor(
    @InjectAnthropicChatModel('sonnet') private readonly model: ChatAnthropic,
    @InjectAnthropicChatModelFactory()
    private readonly factory: AnthropicChatModelFactory,
  ) {}

  critique(input: string) {
    return this.model.invoke(input);
  }

  critiqueWith(model: string, input: string) {
    return this.factory.create({ model }).invoke(input);
  }
}

For dynamic lookup use getAnthropicChatModelToken(name).

Async Connection Info

Use forRootAsync when the API key comes from ConfigService or a secrets manager. Presets stay static:

AnthropicProviderModule.forRootAsync({
  imports: [ConfigModule],
  inject: [ConfigService],
  useFactory: (config: ConfigService) => ({
    apiKey: config.get('ANTHROPIC_API_KEY'),
  }),
  presets: [{ name: 'haiku', model: 'claude-haiku-4-5-20251001' }],
});

Migration (v0.1 → v0.2)

NEST_LANGCHAIN_ANTHROPIC_CHAT_MODEL and the module-level model / temperature options were removed. Replace @Inject(NEST_LANGCHAIN_ANTHROPIC_CHAT_MODEL) with a named preset, or inject the factory with @InjectAnthropicChatModelFactory() and call .create({ model }).

Demo

ANTHROPIC_API_KEY=sk-ant-... pnpm --filter @nest-langchain/demo-providers start
curl -X POST "http://localhost:3006/providers/anthropic/invoke" \
  -H "content-type: application/json" \
  -d '{"prompt":"Write one sentence about critique models."}'