Sebastian Tirelli

Senior AI Engineer with 12+ years in software and 2+ years building production LLM systems. I design and ship multi-agent orchestration pipelines, RAG systems, and real-time AI applications. As founding engineer, built an AI platform end-to-end including agent workflows, prompt management, streaming APIs, and orchestration.

Former Senior Engineering

Manager (35+ engineers), now fully hands-on. UC Berkeley certified in ML/AI.

Principal AI Engineer at Harmony (2025-09 – 2026-04)

• Designed hybrid retrieval workflows (semantic search, lexical matching, re-ranking) improving relevance across LLM applications.
• Built evaluation pipelines (precision, recall, ranking) against academic benchmarks, driving iterative improvements.
• Established evaluation framework that became the system's source of truth for ranking decisions and competitor benchmarking.
• Built internal admin tools (frontend + backend) to inspect and debug retrieval behavior.

Founding AI Engineer at Agentheon (2025-01 – 2025-09)

• Built AI outbound platform end-to-end: lead ingestion, enrichment, personalized generation, real-time feedback loops.
• Designed multi-agent workflows (LangGraph) for research, enrichment, and generation with human-in-the-loop approval.
• Built full Next.js frontend (TypeScript, Tailwind, Auth0, Socket.IO) including campaign management, real-time analytics dashboards, and approval workflows.
• Built composable prompt system with performance feedback injection. Campaigns learn from results automatically.

Senior Engineering Manager at OnTop (2023-09 – 2024-05)

• Led 5 teams (35+ professionals) building an enterprise fintech platform for global contractor payments.
• Reduced processing errors by 40% and support tickets by 40%. Achieved SOC 2 Type II compliance.

Engineering Manager at TestGorilla (2021-08 – 2023-09)

• Sr. Software Engineer → Tech Lead → EM (team of 10). Rebuilt core architecture. Shipped Design System (–30% dev time).

Professional Certificate in Machine Learning and Artificial Intelligence – UC Berkeley (2024 – 2025)

Certificate in Technology Leadership – UC Berkeley (2022 – 2023)

B.S. in Systems Engineering – John F. Kennedy University (2010 – 2015)