You can try adding a TeX-command with this:


(eval-after-load "context"
  '(setq TeX-command-list
    (append
      '(
        ("context"
"context --purgeall %t"
          TeX-run-command t :help "Run context (MarkIV)")
        ("luametatex"
"context --purgeall %t"
          TeX-run-command t :help "Run context (LMTX)")
      ) TeX-command-list
    )
  )
  )

--
Mauricio Reyna