I was slow to adopt an agentic workflow for a variety of reasons. When I was ready to try an agentic workflow, I didn't want to install Claude on my own system. I have a hard time trusting its boundaries, and I don't want to spend a bunch of time learning its permissions model well enough to start trusting it.

I decided to write my own harness, and thought people would find that a pointless thing to do in 2026. I was amazed how easy it was to build a harness that can read, write, and modify files within a project directory. I now use this harness on a daily basis, and it hasn't grown much since that first iteration.

That made me wonder: How many of us are using a custom harness on a regular basis? What keeps you using your own harness?