Hi @tnorthcutt,
Sorry about this! Codeception can be tricky to set up when containers are involved.
Based off of the details, it sounds like you need to look for Webdriver/Selenium at the IP that loopbacks to your Mac/PC instead of 127.0.0.1 which will loopback to the container if used inside the container. Here’s how you can get the host machine’s IP: IP of HOST available within site container?