Probook
Chief Architect
Turn ambitious AI behavior into a production system: measurable, observable, and recoverable when reality disagrees with the plan.
What I’m building →Christian Yongwhan Lim New York
I solve hard technical problems. I build teams that can keep solving them.
Chief Architect at Probook. Director of Internships at the ICPC Foundation. Adjunct at Columbia University.
I work on production AI and competitive programming. In both, the job is the same: define the outcome, attack the hardest assumptions, and build a path other people can carry forward.
01 / Current work
Three roles. One way of working.
ICPC Foundation
Director of Internships
Give talented students consequential work, honest feedback, and mentors who expect them to take ownership.
136 completed internships →Columbia University
Adjunct
Teach students to solve unfamiliar problems, not by memorizing techniques, but by making better decisions under pressure.
Courses and teaching →02 / How I think
Start with the outcome.
Work backward.
- 01
Name the result
If success cannot be observed, it is not yet a useful goal.
- 02
Find the assumption most likely to break
Test that first. Architecture should follow evidence, not fashion.
- 03
Leave a capable owner
A system is not finished if only its original builder can run it.
03 / Evidence
The work should survive inspection.
80/80
136
2×
Reproducibility checks passed
A multi-model evaluation program for identity, voice, conversational continuity, and drift.
ICPC internships completed
A global program designed around real work, accountable mentorship, and student ownership.
World Finals teams coached
Competitive programming as a discipline for judgment, teamwork, and learning from failure.
“He has had a bigger impact in that short time than almost anyone has had in the history of North America.”
04 / Field notes
What I’ve learned by doing the work.
05 / Contact