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Marcello – Python, LLM, AI agent development, experts in Lemon.io

Marcello

From Brazilflag

AI Engineer|Strong senior

Marcello – Python, LLM, AI agent development

Marcello is a Strong Senior AI Engineer with 14 years of experience across machine learning, reinforcement learning, and LLM-based agent systems. He has led end-to-end AI solutions using Python, LangChain, RAG, AWS, and Azure, with a focus on structured data extraction and scalable agent orchestration. He combines strong technical depth with pragmatic decision-making, grounded in real-world constraints and business needs. Marcello is an effective client-facing engineer who communicates clearly, aligns stakeholders, and delivers production-ready systems. His experience spans both startup and enterprise environments, with a hands-on and ownership-driven approach.

14 years of commercial experience in
AI
Fintech
Legal tech
Machine learning
Sports
Gaming software
Main technologies
Python
8 years
LLM
3 years
AI agent development
3 years
RAG
3 years
LangChain
3 years
AWS
4.5 years
Microsoft Azure
2.5 years
Additional skills
Cloud Computing
LangGraph
Machine learning
Deep Learning
Reinforcement Learning
Data Science
Direct hire
Possible
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Experience Highlights

Senior Data Scientist/Machine Learning Engineer
Dec 2025 - Feb 20262 months
Project Overview

Developed an AI assistant for a legal document editing company to support grammar and content review, enhancing editorial efficiency and enabling teams to focus on more complex, high-value tasks.

Responsibilities:
  • Designed and implemented a validation pipeline, establishing accuracy benchmarks as a baseline for continuous model evaluation and improvement;
  • Developed and refined prompt engineering strategies to enhance response quality and consistency;
  • Built and maintained the request processing pipeline, ensuring reliable and efficient handling of AI-driven tasks;
  • Optimized model outputs through iterative tuning, evaluation, and AI benchmarking techniques;
  • Integrated external services via APIs, including the OpenAI API, to enable seamless AI functionality;
  • Developed AI-driven solutions using LangChain, focusing on scalable AI agent development in Python.
Project Tech stack:
LangChain
OpenAI API
Prompt engineering
AI agent development
Python
AI benchmarking
Senior AI Developer/Machine Learning Engineer
Sep 2024 - May 20258 months
Project Overview

LLM-powered extractor agent for converting diverse document formats into structured data, with continuous benchmarking to ensure reliability.

Responsibilities:
  • Built and integrated an LLM-powered extractor agent (Claude 3.5) into new and existing systems;
  • Developed pipelines for extracting data from diverse document formats (TXT, Excel, text PDFs, image PDFs) and converting them into structured outputs for database ingestion;
  • Implemented input data normalization workflows (PDFs, images, text → JSON) to ensure consistent processing;
  • Designed and maintained a validation test bench to monitor performance and prevent regression in extraction accuracy;
  • Conducted LLM model validation using benchmark datasets and defined evaluation metrics;
  • Applied prompt engineering techniques to improve extraction quality and reliability;
  • Implemented tool calling mechanisms to enhance agent capabilities and workflow orchestration;
  • Integrated external services and systems via API integrations.
Project Tech stack:
LangChain
Python
PostgreSQL
AI agent development
AI benchmarking
Senior AI Engineer
Dec 2023 - Apr 20243 months
Project Overview

A chatbot assistant for a fantasy sports app powered by LLMs, designed with RAG, memory management, and vector databases to improve contextual understanding and user interaction.

Responsibilities:
  • Built and integrated an LLM-powered chatbot assistant (GPT-3.5 Turbo) into a fantasy sports application using LangChain;
  • Designed and evaluated different agent architectures, including prompt-based agents, tool calling, and OpenAI tools;
  • Implemented agent memory management to support context-aware and multi-turn interactions;
  • Developed and validated RAG (Retrieval-Augmented Generation) pipelines using vector store databases;
  • Conducted experiments to compare approaches and optimize chatbot performance and reliability;
  • Designed and optimized data storage structures to improve retrieval efficiency and overall agent performance;
  • Performed stress testing and validation to ensure robustness and scalability of the chatbot system.
Project Tech stack:
LangChain
LangGraph
RAG
Vector Databases
AI agent development
Prompt engineering
Senior AI developer
Sep 2021 - Dec 20221 year 3 months
Project Overview

Built human-like game-playing agents with competitive performance using reinforcement learning and neural network optimization for a major U.S. game development company.

Responsibilities:
  • Developed and maintained AI agents capable of human-like gameplay at a high skill level using Deep Reinforcement Learning;
  • Designed and optimized deep learning models (neural network architectures) using PyTorch and TensorFlow;
  • Implemented and trained machine learning pipelines in Python, focusing on agent performance and stability;
  • Applied machine learning and data science techniques to evaluate and improve gameplay behavior;
  • Conducted experiments and performance analysis to refine models and training strategies;
  • Collaborated with game design teams, providing simulation results and insights to support data-driven decisions.
Project Tech stack:
Reinforcement Learning
Deep Learning
Machine learning

Education

2011
Computer Science
Bachelor
2018
Artificial Inteligence
Nanodegree - Deep Reinforcement Learning

Languages

English
Advanced

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