Of all the parameter values for \setupdescriptions[][alternative=value] there is one that fails here, i.e. "right". right is a value mentioned in http://wiki.contextgarden.net/Command/setupdescriptions. Below a minimal example and the error. \definedescription[htmldd][before=,after=] \setupdescriptions[htmldd][alternative=right] \starttext Text before.\crlf \starthtmldd{item-1}description\stophtmldd \starthtmldd{item-2}description\stophtmldd Text after. \stoptext ! Undefined control sequence. system > tex > error on line 5 in file description.tex: Undefined control sequence ... \12>:153>:right:none ...nstructions_pure_hang_box \raggedleft \rlap {\hskip ... \148>construction ...parameter \c!renderingsetup } \relax \dostoptagged \dost... \dodogotopar ...andler \v!construction \endcsname \BeforePar \emptytoks <to be read again> d l.5 \starthtmldd{item-1}d escription\stophtmldd Hans van der Meer