Principal technologist and open-source leader, now building and contributing to open-source AI, hands-on.

I've spent two decades at the intersection of technology, policy, and public service, including leading the U.S. federal government's Open Source Program Office (Code.gov). These days I'm going back to the code: learning modern AI from the source up and contributing to the open-source projects building it.

• Building a federal agentic AI practice by day, contributing to open-source AI by night.
• Going deep on the Model Context Protocol (MCP), agent frameworks, and AI gateways: the layer where LLM traffic meets API infrastructure.
• Shipping small, useful PRs (accessibility, docs, and bug fixes) across projects I actually use.

Projects where I am a community contributor or where a pull request of mine has been reviewed and merged.

AI & LLM tooling

• OpenHands: an open-source platform for AI-driven software development agents.
• AnythingLLM: a self-hostable, all-in-one application for turning documents and content into context for any LLM, with agents and RAG built in.
• Jupyter Chat: the chat interface behind Jupyter AI and other conversational extensions in JupyterLab.

Government design systems

• USWDS: the U.S. Web Design System, helping federal agencies build fast, accessible, mobile-friendly websites.
• GC Design System (Canadian Digital Service): the web components behind Government of Canada digital services.
• GC Design System Docs (Canadian Digital Service): the bilingual documentation site teams use to adopt the GC Design System.
• Web Experience Toolkit (Government of Canada): the open-source library behind accessible, usable, and interoperable Government of Canada websites.

Public sector & open data

• OSPOlogy (TODO Group, Linux Foundation): the community resources behind Open Source Program Offices, including the OSPO Book.
• CKAN: the open-source data management system powering catalog.data.gov, open.canada.ca/data, and data.humdata.org.
• government.github.com: the directory of government organizations using GitHub for open government work.

Financial infrastructure

• Apache Fineract: the back-office UI for Apache Fineract, the open-source core banking platform.

• Government Open Source: An Analysis (repo): a census of the 1,079 government GitHub organizations on governments.yml: 75,638 public repos, how much is still maintained, and how much accepts outside contributions.

I use AI coding assistants to get up to speed on unfamiliar codebases quickly. I read, run, and take responsibility for everything I submit, and if a patch of mine is wrong, that's on me. Reviewer time is the scarcest resource in open source, and I try hard not to waste it.

• VP, Technology Solutions at HumanTouch, LLC: leading AI engineering and agentic-AI workflows on the CORASai platform in collaboration with federal agencies, carrying two decades of open-source and gov-tech leadership into the AI era
• Maryland Governor Appointment to the Council for Open Data: supporting the State Chief Data Officer (CDO) on implementation of SB0200/HB0262 by working with state agencies and local governments to meet the Governor's priorities
• Director, Code.gov: ran the federal Open Source Program Office (OSPO) and grew federal open-source participation from 45 to 7,000 repositories across 20 agencies. Brought the platform into Section 508 compliance and added automated accessibility testing to its CI pipeline
• The White House (Executive Office of the President): developed M-13-13 Open Data Policy Supplemental Guidance and implemented the President's Digital Strategy
• Contributor to federal open-source and AI policy, including the Federal Source Code Policy (codified into law as the SHARE IT Act in 2024) and OMB M-24-10
• GitHub Star, 2021-2024 · Fed100, 2019
• PhD, Public Administration and Public Affairs. Dissertation: An Organizational Analysis of Publishing the People's Code

• LinkedIn: linkedin.com/in/jrcastle

_{Learning in public, contributing to the open-source AI ecosystem one PR at a time.}