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Basics

Name Sachith Gunasekara
Label Senior AI Engineer
Email sachithgunasekara@outlook.com
Url https://sachith-gunasekara.github.io
Summary AI engineer and researcher working on LLM reasoning, instruction tuning, LLM evaluation, multi-agent systems and retrieval-augmented generation.

Education

  • 2019.02 - 2023.07

    Dalugama, Sri Lanka

    Bachelor
    University of Kelaniya
    BSc (Hons) in Computer Science
  • 2017.10 - 2018.04

    Matale, Sri Lanka

    Diploma
    ESOFT Metro Campus
    Software Engineering

Work

  • 2026.02 - Present

    Colombo, Sri Lanka · Hybrid

    Senior AI Engineer
    Gapstars, placed at Envision AI Labs (Leiden, Netherlands)
    • Chose the retrieval embedding model on evidence: built a synthetic question–answer benchmark linked to source records and compared four leading models on recall, nDCG and MRR, with significance tests
    • Building a ground-truth benchmark from client-provided documents to measure retrieval and answer quality on real data
    • Designed the evaluation framework for RAG and agentic systems using LLM-as-a-judge metrics, claim-level faithfulness checks and expert-validated gold-standard datasets
    • Built and benchmarked LLM-based insight-generation features on client-approved pharmaceutical and clinical data
    • Contributed to the multi-agent architecture behind narrative trend generation: hybrid retrieval, guardrails, citation grounding and context management
  • 2025.09 - Present

    Online

    Instructor, AI Engineering Bootcamp
    StemLink
    • Teach an applied LLM curriculum: transformers, prompting, agents (LangChain, LangGraph, AutoGen), RAG (LlamaIndex, Pinecone) and LoRA/QLoRA fine-tuning
    • Supervise capstone builds through to working demos
  • 2025.06 - 2026.02

    Toronto, Canada · Remote

    Senior AI Engineer
    Arcadea Group
    • Automated structured data extraction from a US state police agency's records with an offline multi-agent system of 10+ planning, generation, execution and evaluation agents that write named-group regex patterns
    • Made accuracy verifiable with a generate–test–revise loop scored against ground truth, delivering a validated, reusable regex instead of an ongoing model dependency
    • Built a customer-care assistant grounded in company knowledge and historical phone calls, comparing traditional RAG with graph-based RAG and adding topic modelling and source traceability
  • 2025.04 - 2026.07

    Colombo, Sri Lanka

    Machine Learning Engineer
    Surge Global
    Full-time, then part-time contract
    • Led AI delivery of an orchestrated multi-agent system for an insurance warranty-claims intermediary, giving service technicians a ready recommendation for each claim
    • Researched connecting a real-time GPT-4o voice agent to multi-agent workflows for a founder relationship assistant
  • 2023.10 - 2025.04

    Colombo, Sri Lanka

    Associate Machine Learning Engineer
    Surge Global
    • First author of iSelf-Discover, showing unstructured reasoning plans beat structured JSON plans across BBH, T4D and MATH (up to 18.9% relative on MATH)
    • Co-developed OpenBezoar, a low-cost recipe for small open instruction-following models (synthetic data, QLoRA SFT, DPO)
    • Wrote nanoJAXGPT, a JAX/Equinox rewrite of nanoGPT, as a teaching resource
  • 2023.03 - 2023.10

    Colombo, Sri Lanka

    Data Science Intern
    Surge Global
  • 2018.11 - 2019.02

    Battaramulla, Sri Lanka

    ICT Classroom Teacher
    Steiner College

Volunteer

  • 2024.10 - Present

    Colombo, Sri Lanka

    Judge
    IEEE Young Professionals - Sri Lanka
    Judge at Sri Lanka Artificial Intelligence Competition (SLAIC) 2024
  • 2023.12 - Present

    Colombo, Sri Lanka

    Mentor
    IEEE Young Professionals - Sri Lanka
    Mentor for an AI Bootcamp final competition
  • 2017.11 - 2018.08

    Colombo 7, Sri Lanka

    Secretary and IT Assistant
    International Vipassana Meditation Center
    Secretary and IT Assistant to Chief Incumbent Thero, Ven. Udadumbara Kashyapa Thero
  • Member (pending)
    IEEE P2834 Working Group
    Standard for Secure and Trusted Learning Systems

Awards

Skills

Research areas
LLM reasoning
Instruction tuning
LLM evaluation
Multi-agent systems
Retrieval-augmented generation
Methods
Supervised fine-tuning
LoRA/QLoRA
DPO
Synthetic data generation
LLM-as-a-judge
Calibration
Tools
Python
JAX/Equinox
Hugging Face
LangChain
LangGraph
AutoGen
LlamaIndex
Pinecone

Talks