tcl-prompt-regexp

tcl-prompt-regexp is a variable defined in `tcl.el'.
Its value is

"^\\(% \\|\\)"

Documentation:
If not nil, a regexp that will match the prompt in the inferior process.
If nil, the prompt is the name of the application with ">" appended.

The default is "^\(% \|\)", which will match the default primary
and secondary prompts for tclsh and wish.

You can customize this variable.