1. What's your approach to accessibility? Do you test accessibility of the phoenix.new UI? Considering that many people effectively use Phoenix to write front-ends, have you conducted any evals on how accessible those frontends come out?

2. How do you handle 3rd party libraries? Can the agent access library docs somehow? Considering that Elixir is less popular than more mainstream languages, and hence has less training data available, this seems like an important problem to solve.

It seems like they're giving you lower level building building blocks here. It's up to the developer to address these things. Instruct the agent to build/test for accessibility, feed it docs via MCP or by other means.