Phalcon is a web framework implemented as a C extension , every Phalcon's fan know that. It mean we cannot view source code of framework like another PHP framework.

Thank for Phalcon Developer tool. It provide useful interface & class declaration scripts which support IDE auto complete function.

Assuming that, Phalcon developer tools  is installed.

In Eclipse, you just need to add devtool path : phalcon-devtools/ide/PHALCON_VERSION by adding external Source Folder in PHP include Path / Libraries tab.