diff --git a/include/QF/progs.h b/include/QF/progs.h
index c615e6d14..e2c077e02 100644
--- a/include/QF/progs.h
+++ b/include/QF/progs.h
@@ -1690,6 +1690,15 @@ typedef struct {
 	strref_t   *tstr;				///< Linked list of temporary strings.
 } prstack_t;
 
+typedef enum {
+	prd_none,
+	prd_trace,
+	prd_breakpoint,
+	prd_watchpoint,
+	prd_runerror,
+	prd_error,			// lower level error thann prd_runerror
+} prdebug_t;
+
 struct progs_s {
 	int       (*parse_field) (progs_t *pr, const char *key, const char *value);
 
@@ -1831,7 +1840,9 @@ struct progs_s {
 	/// \name debugging
 	///@{
 	struct prdeb_resources_s *pr_debug_resources;
-	void      (*breakpoint_handler) (progs_t *pr);
+	void      (*debug_handler) (prdebug_t event, void *data);
+	void       *debug_data;
+	const char *error_string;
 	pr_type_t  *watch;
 	int         wp_conditional;
 	pr_type_t   wp_val;
diff --git a/libs/gamecode/pr_exec.c b/libs/gamecode/pr_exec.c
index 397eb7bde..94018943b 100644
--- a/libs/gamecode/pr_exec.c
+++ b/libs/gamecode/pr_exec.c
@@ -62,6 +62,12 @@ PR_RunError (progs_t * pr, const char *error, ...)
 	dvsprintf (string, error, argptr);
 	va_end (argptr);
 
+	if (pr->debug_handler) {
+		pr->error_string = string->str;
+		pr->debug_handler (prd_runerror, pr->debug_data);
+		// not expected to return, but if so, behave as if there was no handler
+	}
+
 	Sys_Printf ("%s\n", string->str);
 
 	PR_DumpState (pr);
@@ -477,12 +483,17 @@ PR_ExecuteProgram (progs_t *pr, func_t fnum)
 		op_b = pr->pr_globals + st->b;
 		op_c = pr->pr_globals + st->c;
 
-		if (pr->pr_trace)
-			PR_PrintStatement (pr, st, 1);
+		if (pr->pr_trace) {
+			if (pr->debug_handler) {
+				pr->debug_handler (prd_trace, pr->debug_data);
+			} else {
+				PR_PrintStatement (pr, st, 1);
+			}
+		}
 
 		if (st->op & OP_BREAK) {
-			if (pr->breakpoint_handler) {
-				pr->breakpoint_handler (pr);
+			if (pr->debug_handler) {
+				pr->debug_handler (prd_breakpoint, pr->debug_data);
 			} else {
 				PR_RunError (pr, "breakpoint hit");
 			}
@@ -1701,8 +1712,12 @@ op_call:
 		if (watch && watch->integer_var != old_val.integer_var) {
 			if (!pr->wp_conditional
 				|| watch->integer_var == pr->wp_val.integer_var) {
-				PR_RunError (pr, "watchpoint hit: %d -> %d",
-							 old_val.integer_var, watch->integer_var);
+				if (pr->debug_handler) {
+					pr->debug_handler (prd_watchpoint, pr->debug_data);
+				} else {
+					PR_RunError (pr, "watchpoint hit: %d -> %d",
+								 old_val.integer_var, watch->integer_var);
+				}
 			}
 			old_val.integer_var = watch->integer_var;
 		}
diff --git a/libs/gamecode/pr_load.c b/libs/gamecode/pr_load.c
index d385dff12..2bae32dfe 100644
--- a/libs/gamecode/pr_load.c
+++ b/libs/gamecode/pr_load.c
@@ -323,6 +323,7 @@ PR_LoadProgsFile (progs_t *pr, QFile *file, int size)
 			def->type_encoding = xdef->type;
 		}
 	}
+	pr->error_string = 0;
 	pr->pr_trace = 0;
 	pr->pr_trace_depth = 0;
 	pr->pr_xfunction = 0;
@@ -485,5 +486,10 @@ PR_Error (progs_t *pr, const char *error, ...)
 	dvsprintf (string, error, argptr);
 	va_end (argptr);
 
+	if (pr->debug_handler) {
+		pr->error_string = string->str;
+		pr->debug_handler (prd_error, pr->debug_data);
+		// not expected to return, but if so, behave as if there was no handler
+	}
 	Sys_Error ("%s: %s", pr->progs_name, string->str);
 }