How to build a coding agent

We (the Princeton SWE-bench team) built an agent in ~100 lines of code that does pretty well on SWE-bench, you might enjoy it too: https://github.com/SWE-agent/mini-swe-agent

> 1. Analyze the codebase by finding and reading relevant files 2. Create a script to reproduce the issue 3. Edit the source code to resolve the issue 4. Verify your fix works by running your script again 5. Test edge cases to ensure your fix is robust

This prompt snippet from your instance template is quite useful. I use something like this for getting out of debug loops:

> Analyse the codebase and brainstorm a list of potential root causes for the issue, and rank them from most likely to least likely.

Then create scripts or add debug logging to confirm whether your hypothesis is correct. Rule out root causes from most likely to least by executing your scripts and observing the output in order of likelihood.