The mongoc_client_pool_push docs should say that the client is destroyed if it exceeds the uri configured min_pool_size.

the pop function should also say when a new client is created and how that is configured.

the connection string docs for those values may also need improvements to restate how it works as it isn't identical with other implementations as pointed out by david.golden

The way that's written sounds more like a "maximum number of idle connections in the pool" which isn't how I usually understand minpoolsize

Contrast with pymongo: https://api.mongodb.com/python/current/faq.html#how-does-connection-pooling-work-in-pymongo