$ cat post/cron-job-i-forgot-/-a-system-i-built-by-hand-/-i-pushed-and-forgot.md

cron job I forgot / a system I built by hand / I pushed and forgot


Title: Ephemeral Debugging Sessions with Claude 3.7


February 24, 2025 feels like a strange mix of the mundane and the mystical. The office is humming with chatter about AI-native tools—Claude 3.7 being the latest darling. I’ve been spending more time than I care to admit with this new version, trying to wrangle some actual productivity out of it.

The other day, I was working on a multi-cloud project where we’re integrating eBPF for deep performance tuning. Our platform team is now owning end-to-end AI infrastructure pipelines, so everything from training models to deploying them in production is under our purview. That means dealing with Claude and the rest of the LLMs, as well as the more traditional ops tools.

I was trying to debug a tricky eBPF program that seemed to be causing some strange behavior on one of our Kubernetes clusters running in AWS. I decided to try out Claude 3.7 for some guidance. After all, the era of hype is long behind us, and now it’s about getting things done with these tools.

I fired up my terminal and typed:

claude run

After a few minutes of setup, I was greeted by Claude in a chat-like interface. The first thing it asked me to do was clarify what exactly the issue was. I explained that we were seeing some strange behavior with our eBPF program on one of the Kubernetes pods. It asked for details about the code and context.

I walked through the code, explaining how the eBPF program was supposed to work in detail. Claude listened patiently, then started asking questions to clarify specific sections. I found myself re-explaining things I thought were obvious, but it turned out to be helpful to get a fresh perspective. After about 20 minutes of back and forth, Claude suggested some potential issues with the program.

One of its suggestions was to add a probe_read function to ensure that we weren’t reading invalid memory addresses in our eBPF program. I decided to give it a shot, as the suggestion seemed like a reasonable debugging step. I added the probe read and re-ran the program. The strange behavior persisted.

Feeling a bit frustrated, I fired off another prompt:

claude run --debug

This time Claude went into more detail about how eBPF programs are compiled and loaded, pointing out potential pitfalls in our code that we hadn’t thought of before. It even suggested some additional logging to help us trace the flow of data through the program.

I implemented the new logging and ran the program again. This time, it was clear that there was an issue with how the function pointers were being set up. I went back to the original code and made a few tweaks based on Claude’s insights. After a few more iterations, we finally got everything working as expected.

Reflecting on this session, I realized that while AI tools like Claude are incredibly powerful, they aren’t always perfect. They can be great for getting second opinions or fresh perspectives, but ultimately the human touch is still necessary to make sense of complex systems. The eBPF program was a good test case—there were some nuances that only experience could fully understand.

Debugging with Claude was like having an extra set of eyes and ears in my brain. It saved me from spending hours going down dead ends and provided valuable insights that I might not have considered otherwise. But at the end of the day, it’s about understanding your tools well enough to use them effectively—and sometimes knowing when to step back and think things through on your own.

In the age of AI-native tooling, I’ve come to appreciate the balance between leveraging these powerful aids and maintaining a deep understanding of the systems we’re working with. It’s an ongoing journey, but one that keeps the work interesting and challenging.