[robertlagrant]

> 2. It encourages poor API contracts because it lets anyone import any code in any service arbitrarily. Shared functionality should be exposed as a standalone library with a clear, well-defined interface boundary. There are entire packaging ecosystems like npmjs and pypi for exactly this purpose.

I don't believe this is true, except in the short term. Unless the writing party is guaranteeing you forward compatibility, your consuming code will break when you update.

This is (almost) the only reason API contracts are worth having; the reason doesn't go away just because you can technically see all the code.