ModTweaker's Thaumcraft integration extends the command palette provided by CraftTweaker.
To access these commands you do the same as you do for CraftTweaker commands, you use the /crafttweaker prefix
List of Thaumcraft's Commands
Link to list-of-thaumcrafts-commands
thaumcraftDump
Link to thaumcraftdump
Usage:
/crafttweaker thaumcraftDump
/ct thaumcraftDump
Description: Dumps all the Thaumcraft information to the crafttweaker.log file.