Agentic Systems
Planner and executor loops · tool calling · browser agents · multi-agent orchestration · MCP
No. 001 / Personal Site / MMXXVI
Principal AI Architect · 3x Technical Founder & Hands-On CTO
Matthew J. Ernewein
Bio
What I do, briefly.
Production AI.
Hands on.
Three decades in.
I am a technologist and hands-on technical founder who designs and builds enterprise-scale systems, along with the occasional small thing that proves genuinely useful.
My current work is production agentic AI: workflow orchestration, retrieval, document intelligence, local-first inference, and the platform controls that make AI systems dependable across SaaS, on-premises, edge, and local-device environments.
Before Hyacinth AI, I co-founded Zeal Technology and Engaged, building cloud-native platforms, real-time analytics, NLP, and enterprise workflow systems. Earlier work covered HR technology, marketing, publishing, legal information, social analytics, search, integration, and large-scale software modernization.
I care about mentoring and teams that ship together. Across every technology wave, the goal has remained the same: build adaptive, user-centered systems that fit how people actually work.
I trained as an artist at RIT, where I also earned a Master of Science. I write at decahedron.blog.
Current Focus
What I'm building now.Agents are only as reliable as the platform underneath them.
At Hyacinth AI, I own AI systems architecture, platform engineering, and implementation from prototype through production. My approach combines AI systems design, classic enterprise architecture, and cloud automation. I am focused on:
- Multi-model orchestration for deterministic DSL-scripted workflows and governed autonomous agent workflows.
- Agentic developer workflows.
- Lights-on software factories: agentic pipelines where humans remain in the loop and every step is observable.
- Evaluation, guardrails, human review, and operational controls that establish trust in what agents ship.
- Local-first retrieval and inference that keeps data where it already lives.
I welcome confidential conversations with leaders building consequential enterprise AI systems, especially where hands-on architecture, production implementation, and founder-level ownership matter. Get in touch.
Experience
Thirty years, most recent first.-
2023→Now
Hyacinth AI
Technical Co-Founder & Hands-On CTO · Burlington, MA
Co-founder and hands-on technical leader for an enterprise AI platform focused on document intelligence and zero-code LLM automation. I own AI systems architecture, platform engineering, and implementation from prototype through production.
Orchestration and Platform
- Designed and delivered Roboto, a domain-specific language (DSL), execution model, and multi-model orchestration platform for deterministic scripted workflows and governed autonomous agent workflows; built visual and code-level IDEs that enabled technical and non-technical users to design, test, deploy, and operate advanced agentic AI workflows.
- Built production agentic systems for multi-tenant SaaS, on-premises, edge, and local-device environments.
- Built tenant-aware research pipelines: parallel search, fetch, and ranking, re-querying when evidence is weak, and cited briefings as output.
Controls and Accountability
- Designed enterprise controls and a time-tiered retention architecture for agent observability artifacts, balancing low-latency debugging, evaluation, human review, security, auditability, and cost-effective long-term evidence retention.
- Built agentic developer workflows and observable “lights-on” software-factory pipelines, where humans remain accountable for what ships.
- Hardened agents against prompt injection with explicit boundaries between instructions and retrieved content.
Retrieval and Inference
- Built enterprise document intelligence on OCR and hybrid lexical and dense retrieval, with citations back to source.
- Built local indexing and retrieval across large private information libraries, running entirely on user-controlled devices with an auditable log of every outbound call.
- Established a shared local inference layer with hardware-sized model tiers and pinned, reproducible environments.
- Co-authored "Per-Query Environmental Accounting for Local-First AI."
Outcomes
- Clinical-review cycles reduced from days to minutes.
- Contract-review workflows reduced from hours to minutes.
Python · TypeScript · Node.js · React · Vue.js · AWS · AWS Bedrock · Kubernetes · Docker · Terraform · CI/CD · open-source LLMs and frontier models · agentic AI · multi-agent workflows · multi-model orchestration · MCP · RAG · prompt and context engineering · evaluation · guardrails · human-in-the-loop workflows · OCR · document intelligence · graph databases · vector databases · embeddings · REST APIs · HATEOAS-based agentic discovery · multi-tenant SaaS · observability · enterprise security · authorization · auditability · production AI systems
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Jan 2020→Jul 2023
Zeal Technology
Technical Co-Founder & CTO · Burlington, MA
Co-founded and led technology for a cloud-native digital-adoption platform. Owned platform architecture, technical strategy, hands-on implementation, engineering execution, and board-level technology input.
- Architected and built a multi-tenant SaaS platform on AWS and Kubernetes, balancing performance, reliability, scalability, and operating cost.
- In 2022–23, directed applied R&D with LLMs and LangChain, evaluating practical product uses and translating technical findings into product and platform strategy. That work informed later agentic-AI platform architecture.
- Prototyped Jev throughout the platform for decision trees and automated model selection in agentic workflows.
- Mentored the engineering team and established its delivery practices.
AWS · Kubernetes · Docker · Node.js · TypeScript · Vue.js · Python · AWS Lambda · Amazon DocumentDB · multi-tenant SaaS · cloud-native architecture · microservices · REST APIs · CI/CD · machine learning · LLM applications with LangChain · Jev
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2016→Dec 2019
Engaged
Technical Co-Founder & CTO · Burlington, MA
Co-founded and led technology for a real-time employee-engagement platform that helped organizations understand workforce sentiment, culture, and morale. Owned product architecture, hands-on development, technical strategy, hiring, and delivery. Acquired January 2020.
- Architected and built a cloud-native, multi-tenant service platform on AWS and Kubernetes with Slack and Microsoft Teams integrations.
- Built real-time feedback, analytics, and workflow capabilities that turned employee input into actionable insight for organizational leaders.
- Implemented AI-assisted chatbot and natural-language-processing capabilities, applying machine learning and text analytics to employee feedback and conversational workflows.
- Recruited and mentored the engineering organization, establishing Agile delivery, CI/CD, quality practices, and predictable execution.
AWS · Kubernetes · Docker · Java · Node.js · TypeScript · Vue.js · Python · MongoDB · PostgreSQL · NLP · NLU · machine learning · text analytics · sentiment analysis · conversational AI · chatbots · Slack · Microsoft Teams · REST APIs · cloud-native microservices · multi-tenant SaaS · CI/CD · Agile SDLC
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May 2015→May 2016
Crescendo Content Marketing
Principal Software Architect / VP of Technology · Woburn, MA
Led hands-on architecture and implementation while establishing the engineering organization, delivery model, and cloud-native product platform needed for market entry.
- Architected and delivered the company's cloud-native platform and core intellectual property in 14 weeks, enabling a time-critical market launch.
- Recruited, mentored, and grew a 13-person engineering team. Established an Agile lifecycle, automated testing, and end-to-end CI/CD, sustaining more than 90% test coverage.
Cloud-native architecture · SaaS platforms · AWS · web applications · Agile SDLC · software architecture · automated testing · CI/CD · DevOps · engineering leadership · product delivery
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May 2012→Apr 2015
Percussion Software
VP of Technology / Principal Software Architect · Woburn, MA
Led technology strategy, architecture, hands-on development, hiring, and engineering delivery for a content-platform company.
- Architected and delivered a next-generation cloud platform on REST APIs, microservices, Node.js, and NoSQL, materially improving horizontal scalability and reducing time to market.
- Rebuilt the flagship enterprise CMS as a containerized, single-tenant SaaS with ephemeral containers and roll-forward and roll-back upgrades.
- Recruited and mentored a 16-person engineering organization, increasing team capacity by 80%. Established Agile delivery, CI/CD, and a regular release cadence.
REST APIs · microservices · Angular · Node.js · JavaScript · NoSQL · cloud platforms · distributed systems · horizontal scaling · CI/CD · DevOps · Agile SDLC · software architecture · engineering leadership
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2012→2012
Visible Technologies
Agile Coach / Principal Engineer · Burlington, MA
- Established a shared Agile SDLC, work-tracking, and change-management system across two distributed teams of 21 developers.
- Transitioned work from offshore contractors to employee teams, improving quality and eliminating approximately $400K in annual cost.
Agile SDLC · distributed-team delivery · work tracking · change management · software development lifecycle · engineering process improvement · technical leadership
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2011→2012
Thomson Reuters
Senior Software Architect · Boston, MA
- Designed and implemented a data-discovery layer for SharePoint and enterprise search in legal-information products.
- Prototyped a HATEOAS-based discovery layer for legal-matter data, setting an architectural direction for context-aware navigation.
Enterprise search · SharePoint · data discovery · HATEOAS · REST APIs · legal technology · information architecture · software architecture · enterprise integration
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2009→2011
Saba
Principal Engineer · Lexington, MA
- Refactored more than 250K lines of code into reusable components and modules, and modernized build, deployment, and upgrade technology.
- Expanded automated test coverage across a 3M+ line codebase from 0% to more than 85%, and coached an Agile, test-driven SDLC across three global development locations. Moved releases from every six months to monthly.
Java · enterprise software · CI/CD · build automation · deployment automation · upgrade technology · component architecture · modularization · automated testing · test-driven development · code coverage · Agile SDLC · distributed engineering · software quality
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2000→2009
Kronos (now UKG)
Senior Software Architect · Chelmsford, MA
Led hands-on architecture and delivery across six workforce-management initiatives spanning enterprise integration, rules engines, notifications, large-scale upgrades, search, and platform performance.
- Architected Workforce Integration Manager, a discovery-based framework connecting Kronos servers to external enterprise systems, substantially improving integration performance over its predecessor. Led SAP integration and certification.
- Led the replacement of three core business-rules engines across a heavily integrated 1M+ line codebase, with more than 90% test coverage.
- Architected a distributed upgrade solution adopted across hundreds of customer installations, directing technical work involving 60+ people. Cut enterprise database upgrades from weeks to hours.
- Designed the Kronos Notification Framework, providing broad system-wide monitoring and notification coverage. Improved Lexical Query Generator performance more than 9.5x.
Java · enterprise integration · integration frameworks · SAP integration and certification · distributed systems · rules engines · notification frameworks · upgrade automation · performance engineering · query optimization · enterprise search · Agile delivery · automated testing · workforce-management software
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1994→2000
Softlock / Digital Goods, Libera, Independent
Principal Technologist / Software Engineer / Independent Developer
- Built e-commerce and DRM systems at Softlock / Digital Goods, OCR document processing and search at Libera, and an independent food-service ERP with demand forecasting.
Education
- MS; BA. Rochester Institute of Technology
Capabilities
Grouped by what they do.Workflow Languages & Orchestration
DSL and execution-model design · deterministic state · retries and loop detection · event-driven messaging
Retrieval & Document Intelligence
OCR · hybrid lexical and dense retrieval · embeddings · graph and vector databases · citations · large private corpora
Inference, Anywhere
Hosted and local models · multi-provider routing · hardware-sized model tiers · cloud, on-premises, edge, and local-device deployments
Reliability & Accountability
Observability · evaluation · guardrails · human-in-the-loop review · authorization · auditability · tenant isolation
Platforms
Python · TypeScript · Java · Kubernetes · Terraform · AWS · PostgreSQL · MongoDB · Redis · RabbitMQ
Writing and Art
Writing and art.Contact
Selective, confidential.
Let's
talk.
Open to selective, confidential conversations about enterprise AI architecture, agentic systems, and hands-on technical leadership. LinkedIn is the most reliable way to reach me.