Lucas – Python, LLM, RAG, experts in Lemon.io

Lucas

From Brazil (UTC-3)flag

AI Engineer|Strong senior
AI Agent Architect|Strong senior

Lucas – Python, LLM, RAG

Lucas is a Principal AI Engineer with deep expertise in LLMs, RAG, agentic systems, and Python, combining strong architecture skills with hands-on delivery. He has led end-to-end AI initiatives across fintech, healthcare, insurance, and marketplaces, including systems serving over 100,000 users daily. His experience spans multi-agent architectures, LLM observability and evaluation, multimodal AI, and building AI products from concept through deployment. Lucas communicates complex technical concepts clearly and is comfortable owning projects from early discovery and solution design through production delivery.

9 years of commercial experience
Main technologies
Python
8 years
LLM
2.5 years
RAG
2.5 years
LangChain
2.5 years
FastAPI
2.5 years
LangGraph
2.5 years
PyTorch
1.5 years
Pinecone
2.5 years
Multi-Agent Systems
1 year
Additional skills
Celery
RabbitMQ
Supabase
Sentry
React
Data Science
MLOps
Direct hire
Possible
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Experience Highlights

Principal AI Engineer
Jan 2026 - Ongoing6 months
Project Overview

A digital product for automatic refund processing for over 100K users daily.

Responsibilities:
  • Built the Bill Negotiator feature end to end – an agentic system that plans and runs bill-reduction negotiations with providers via autonomous voice agents, covering agent design, action-plan reasoning, and outcome interpretation;
  • Designed voice AI agents (VAPI) that place real calls to providers, navigate phone menus and hold loops, and recover from failures with retry logic and an automated evaluation engine;
  • Architected the multi-agent orchestration – supervisor routing, tool-calling agents, and human-in-the-loop gates that let agents pause mid-negotiation to collect user data or approvals and resume safely, with Slack integration for live oversight;
  • Built a self-hosted, domain-fine-tuned LLM classifier (PyTorch) for a high-load email classification engine, cutting cost while improving accuracy on the email domain;
  • Own LLM evaluation and observability across the stack – custom evaluation engines, Langfuse tracing, and prompt optimization to keep agent behavior measurable and reliable in production;
  • Led model serving and reliability – LLM serving with fallbacks, exponential backoff, and health checks; resolved recurring production incidents surfaced through Sentry;
  • Own the product end to end, including the supporting infrastructure – async email ingestion and an event-driven notification layer (Event Broker on FastAPI + Celery) that keep the agentic workflows fast and decoupled.
Project Tech stack:
Python
FastAPI
LLM
RAG
LangGraph
LangChain
Supabase
Celery
Sentry
Voice AI integration
PyTorch
vLLM
LLM evaluation
Prompt engineering
Redis
PostgreSQL
Docker
Principal AI Engineer
Feb 2025 - Mar 20261 year 1 month
Project Overview

Multiple AI agent and LLM-powered projects spanning document processing, conversational assistants, data copilots, and automated report generation.

Responsibilities:
  • Translated business challenges into AI opportunities and defined actionable implementation roadmaps across fintech, insurance, healthcare, legal tech, and marketplace projects;
  • Delivered the company’s first AI-enabled product: an intelligent matching system for a services marketplace;
  • Designed and delivered a multi-agent AI system for veterinary healthcare using LLMs, agent frameworks, tool-calling architectures, and Langfuse for observability and tracing, covering history management, context orchestration, and external database access;
  • Contributed to 30+ AI/GenAI proposals, defining technical approaches, scope, and feasibility during pre-sales;
  • Provided technical oversight for multi-phase AI initiatives across regulated healthcare and compliance domains;
  • Mentored engineers transitioning into AI development, providing technical guidance and supporting the adoption of AI engineering practices.
Project Tech stack:
Python
FastAPI
React
Typescript
OpenAI
LLM
RAG
PyTorch
Pandas
NumPy
Scikit-learn
Microsoft Azure
Vector Databases
AI Lead
Oct 2023 - Feb 20251 year 4 months
Project Overview

Multiple ML and AI projects across sales, business development, and healthcare domains.

Responsibilities:
  • Acted as a trusted advisor to senior stakeholders, articulating the potential of AI and GenAI in transforming business outcomes and fostering strategic partnerships;
  • Led the end-to-end development of AI and GenAI products from conceptualization to deployment;
  • Collaborated with cross-functional teams, including business development, to define client engagement strategies, provide architectural guidance, and deliver execution roadmaps;
  • Developed technical and commercial proposals by understanding client requirements, designing tailored AI and GenAI solutions, and defining execution plans;
  • Educated internal teams and external clients on cutting-edge AI capabilities;
  • Drove initiatives to build internal critical mass in emerging AI technologies;
  • Mentored and guided junior team members, fostering professional growth and advancing organizational AI expertise.
Project Tech stack:
AI
MLOps
Python
LLM integration
OpenAI
LangChain
AI benchmarking
Senior Data Scientist
Mar 2022 - Sep 20231 year 5 months
Project Overview

Worked on projects for a large food services global company and a hospitality company

Responsibilities:
  • Worked in multidisciplinary projects, generating value through data science solutions inside product-oriented delivery;
  • Understood business problems and translated them into data science problems;
  • Led data science solutions end-to-end, from experiment conception to deployment;
  • Provided technical leadership to teams building data-oriented solutions;
  • Guided stakeholders and teammates toward reasonable decisions concerning data and data science;
  • Engaged stakeholders and proposed new data science projects with high business value;
  • Prepared and presented Data and AI commercial proposals.
  • Mentored peers;
  • Participated in MLOps forums for CI/CD best practices for ML.
Project Tech stack:
Data Science
Machine learning
CI
CD
Senior Data Scientist
Dec 2021 - Feb 20222 months
Project Overview

Brazil’s first social commerce platform, enabling consumers to access lower prices through group purchasing while connecting merchants and customers through a digital marketplace.

Responsibilities:
  • Delivered data science initiatives aimed at improving customer experience and product insights;
  • Identified business problems and designed and evaluated data science solutions through experimentation;
  • Built an experimental pipeline for cleaning and classifying user-generated comments within the application;
  • Mentored junior and mid-level team members, providing technical guidance and support.
Project Tech stack:
Data Science
PyTorch
GCP
Middle Data Scientist
Oct 2020 - Nov 20211 year
Project Overview

Developed the institution’s first ML-based student retention initiative, building a predictive model to identify students at risk of dropping out at the beginning and end of each semester using academic performance and socioeconomic data.

Responsibilities:
  • Designed and implemented data science and ML projects to support corporate business decisions, translating business problems into DS problems;
  • Built data extraction and transformation pipelines feeding downstream analytics and models;
  • Delivered fast analytics experiments and visualizations to guide decision-making during projects;
  • Ran ML experiments with feature engineering, model validation, and testing to support knowledge discovery.
Project Tech stack:
Python
Airflow
Docker
SQL
FastAPI

Education

2026
Computational Intelligence
Doctor of Philosophy - PhD
2022
Computational Intelligence
Master of Science - MS
2018
Eletrical Engineering
Bachelor

Languages

Portuguese
Advanced
English
Advanced

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