"This mod enables Mekanism's chemical processing system to directly handle and refine GregTech ores."
Why this fits:
Direct: States the core function ("enables... to directly handle and refine").
Specific: Names both mods ("Mekanism", "GregTech") and the system involved ("chemical processing").
No Fluff: Omits marketing language, focusing purely on technical integration.
Clear Scope: Explicitly links GT ores → Mek processing.
If even shorter is needed:
"Adds GregTech ore support to Mekanism's chemical processing."
