Jedi is a static analysis tool for Python that is typically used in IDEs/editors plugins. Jedi has a focus on autocompletion and goto functionality. Other features include refactoring, code search and finding references.

Jedi has a simple API to work with. There is a reference implementation as a VIM-Plugin. Autocompletion in your REPL is also possible, IPython uses it natively and for the CPython REPL you can install it. Jedi is well tested and bugs should be rare.