The Gomill library
Gomill is intended to be useful as a Python library for developing GTP- and SGF-based tools.
As of Gomill 0.8.2, not all of the library API is formally documented. Only the parts which are described in this documentation should be considered stable public interfaces.
Nonetheless, the source files for the remaining modules contain fairly detailed documentation, and the example scripts illustrate how some of them can be used.