Learn how to integrate Pickaxe agents into your NestJS application using dependency injection and decorators.

​
Installation

Install the Pickaxe SDK and required dependencies:

npm install @hatchet-dev/pickaxe
npm install @nestjs/config # For environment configuration

​
Agent Setup

Create your agent definition (src/agents/my-agent.ts):

import { pickaxe } from "@hatchet-dev/pickaxe";
import z from "zod";

const MyAgentInput = z.object({
  message: z.string(),
  userId: z.string().optional(),
});

const MyAgentOutput = z.object({
  response: z.string(),
  processedAt: z.string(),
});

export const myAgent = pickaxe.agent({
  name: "my-nestjs-agent",
  description: "Agent for NestJS application",
  inputSchema: MyAgentInput,
  outputSchema: MyAgentOutput,
  executionTimeout: "5m",
  fn: async (input, ctx) => {
    ctx.logger.info(`Processing message for user: ${input.userId}`);
    
    // Your agent logic here
    return {
      response: `Processed: ${input.message}`,
      processedAt: new Date().toISOString(),
    };
  },
});

​
Service Integration

Create a service to handle agent operations (src/agents/agent.service.ts):

import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Hatchet } from '@hatchet-dev/typescript-sdk';
import { myAgent } from '@/agents/my-agent';

@Injectable()
export class AgentService implements OnModuleInit {
  private readonly logger = new Logger(AgentService.name);
  private hatchet: Hatchet;

  constructor(private configService: ConfigService) {}

  async onModuleInit() {
    try {
      this.hatchet = Hatchet.init({
        token: this.configService.get<string>('HATCHET_CLIENT_TOKEN'),
        serverUrl: this.configService.get<string>('HATCHET_SERVER_URL'),
      });

      await this.hatchet.registerWorkflows([myAgent]);
      this.logger.log('Hatchet workflows registered successfully');
    } catch (error) {
      this.logger.error('Failed to initialize Hatchet', error);
      throw error;
    }
  }

  async runAgent(input: { message: string; userId?: string }) {
    try {
      this.logger.log(`Running agent with input: ${JSON.stringify(input)}`);
      
      const result = await myAgent.run(input);
      
      this.logger.log(`Agent completed successfully`);
      return result;
    } catch (error) {
      this.logger.error('Agent execution failed', error);
      throw new Error('Agent execution failed');
    }
  }

  async runAgentAsync(input: { message: string; userId?: string }) {
    try {
      this.logger.log(`Starting async agent with input: ${JSON.stringify(input)}`);
      
      const workflowRef = await myAgent.runNoWait(input);
      
      this.logger.log(`Agent started with run ID: ${workflowRef.runId}`);
      return { runId: workflowRef.runId };
    } catch (error) {
      this.logger.error('Failed to start agent', error);
      throw new Error('Failed to start agent');
    }
  }

  async getAgentResult(runId: string) {
    try {
      // Implementation depends on your Hatchet client setup
      // This is a placeholder for getting results by run ID
      this.logger.log(`Getting result for run ID: ${runId}`);
      
      // You would implement this based on your Hatchet client
      // return await this.hatchet.getWorkflowResult(runId);
      
      throw new Error('Method not implemented');
    } catch (error) {
      this.logger.error('Failed to get agent result', error);
      throw new Error('Failed to get agent result');
    }
  }
}

​
Controller Implementation

Create a controller to expose agent endpoints (src/agents/agent.controller.ts):

import {
  Controller,
  Post,
  Body,
  Get,
  Param,
  HttpException,
  HttpStatus,
  Logger,
} from '@nestjs/common';
import { AgentService } from './agent.service';

export class RunAgentDto {
  message: string;
  userId?: string;
}

export class AgentResponse {
  response: string;
  processedAt: string;
}

export class AsyncAgentResponse {
  runId: string;
}

@Controller('agents')
export class AgentController {
  private readonly logger = new Logger(AgentController.name);

  constructor(private readonly agentService: AgentService) {}

  @Post('run')
  async runAgent(@Body() dto: RunAgentDto): Promise<AgentResponse> {
    try {
      this.logger.log(`Running agent for message: ${dto.message}`);
      
      const result = await this.agentService.runAgent({
        message: dto.message,
        userId: dto.userId,
      });

      return result;
    } catch (error) {
      this.logger.error('Agent execution failed', error);
      throw new HttpException(
        'Agent execution failed',
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }

  @Post('run-async')
  async runAgentAsync(@Body() dto: RunAgentDto): Promise<AsyncAgentResponse> {
    try {
      this.logger.log(`Starting async agent for message: ${dto.message}`);
      
      const result = await this.agentService.runAgentAsync({
        message: dto.message,
        userId: dto.userId,
      });

      return result;
    } catch (error) {
      this.logger.error('Failed to start agent', error);
      throw new HttpException(
        'Failed to start agent',
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }

  @Get('result/:runId')
  async getAgentResult(@Param('runId') runId: string) {
    try {
      this.logger.log(`Getting result for run ID: ${runId}`);
      
      const result = await this.agentService.getAgentResult(runId);
      return result;
    } catch (error) {
      this.logger.error('Failed to get agent result', error);
      throw new HttpException(
        'Failed to get agent result',
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }
}

​
Module Configuration

Create and configure the agent module (src/agents/agent.module.ts):

import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';
import { AgentService } from './agent.service';
import { AgentController } from './agent.controller';

@Module({
  imports: [ConfigModule],
  controllers: [AgentController],
  providers: [AgentService],
  exports: [AgentService],
})
export class AgentModule {}

Update your main app module (src/app.module.ts):

import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';
import { AgentModule } from './agents/agent.module';

@Module({
  imports: [
    ConfigModule.forRoot({
      isGlobal: true,
    }),
    AgentModule,
  ],
})
export class AppModule {}

​
Environment Configuration

Configure your environment variables (.env):

HATCHET_CLIENT_TOKEN=your_token_here
HATCHET_SERVER_URL=https://app.hatchet.run

​
Advanced Usage

​
Using Guards and Interceptors

Add authentication and logging:

import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';
import { UseGuards, UseInterceptors } from '@nestjs/common';

@Injectable()
export class AuthGuard implements CanActivate {
  canActivate(context: ExecutionContext): boolean {
    // Your authentication logic
    const request = context.switchToHttp().getRequest();
    return !!request.headers.authorization;
  }
}

@Controller('agents')
@UseGuards(AuthGuard)
export class AgentController {
  // Your controller methods
}

​
Background Processing with Queues

For production use, consider integrating with Bull Queue:

npm install @nestjs/bull bull
npm install @types/bull

import { Injectable } from '@nestjs/common';
import { InjectQueue } from '@nestjs/bull';
import { Queue } from 'bull';

@Injectable()
export class AgentQueueService {
  constructor(@InjectQueue('agent') private agentQueue: Queue) {}

  async queueAgentRun(data: { message: string; userId?: string }) {
    const job = await this.agentQueue.add('run-agent', data, {
      attempts: 3,
      backoff: {
        type: 'exponential',
        delay: 2000,
      },
    });

    return { jobId: job.id };
  }
}

​
Testing

Create unit tests for your agent service:

import { Test, TestingModule } from '@nestjs/testing';
import { ConfigService } from '@nestjs/config';
import { AgentService } from './agent.service';

describe('AgentService', () => {
  let service: AgentService;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        AgentService,
        {
          provide: ConfigService,
          useValue: {
            get: jest.fn((key: string) => {
              const config = {
                HATCHET_CLIENT_TOKEN: 'test-token',
                HATCHET_SERVER_URL: 'http://test-url',
              };
              return config[key];
            }),
          },
        },
      ],
    }).compile();

    service = module.get<AgentService>(AgentService);
  });

  it('should be defined', () => {
    expect(service).toBeDefined();
  });

  // Add more tests here
});