Wow, I just installed it and tested it out - pgcli is remarkable! This is going to be revolutionary for my psql command-line forays! The auto-complete is fantastic.
I'm a huge fan of CLIs. Especially REPLs. When I first encountered BPython (http://www.bpython-interpreter.org/), I fell in love with it. BPython is a Python REPL that has auto-completion, syntax-highlighting and displays the docstring of functions as you type. Once you get used to that level of pampering, all other REPLs start to look like Dumb Terminals.
When I started using psql for interacting with my Postgres database, I yearned for a BPython equivalent for psql.
One fine day I got a twitter DM from Jonathan Slenders asking me if I'd be interested in trying a new Python library that he's working on called Python-Prompt-Toolkit. This library provided a way to write CLIs without having to deal with curses and had the requisite tools for doing auto-completion and syntax-highlighting. So I jumped at the opportunity to try it out. After I got myself familiarized, I started writing pgcli to scratch my own itch.
So this app exists because Jonathan was kind enough to request my feedback.
The source code is available on GH: https://github.com/amjith/pgcli
OP: why no "Fork Me" banner? ;)