diff --git a/tests/debugger/cond.exp b/tests/debugger/cond.exp
index 4a482e1ce..bdd156804 100644
--- a/tests/debugger/cond.exp
+++ b/tests/debugger/cond.exp
@@ -106,14 +106,16 @@ mdb> condition Y^1^2 = 1
             Y ^1^2 = 1
 mdb> continue
 mdb: couldn't evaluate break point condition
-Y ^1^2 = 1: there is no such variable.
+    Y ^1^2 = 1.
+The error is: there is no variable named Y.
      E15:    C15 CALL pred cond.r/2-0 (det)
 mdb> condition -p Y^1^2 = 1
  0: + stop  interface pred cond.r/2-0 (det)
             -p Y ^1^2 = 1
 mdb> continue
 mdb: couldn't evaluate break point condition
-Y ^1^2 = 1: there is no such variable.
+    Y ^1^2 = 1.
+The error is: there is no variable named Y.
      E16:    C16 CALL pred cond.r/2-0 (det)
 mdb> delete *
  0: E stop  interface pred cond.r/2-0 (det)
@@ -159,7 +161,8 @@ mdb> condition X^4 = 1
             X ^4 = 1
 mdb> continue
 mdb: couldn't evaluate break point condition
-X ^4 = 1: the path 4 does not exist.
+    X ^4 = 1.
+The error is: the path 4 does not exist.
      E22:    C21 CALL pred cond.r/2-0 (det)
 mdb> print
 r(1, _)
diff --git a/trace/mercury_trace_internal.c b/trace/mercury_trace_internal.c
index 3b21e4191..635c59cea 100644
--- a/trace/mercury_trace_internal.c
+++ b/trace/mercury_trace_internal.c
@@ -213,11 +213,22 @@ MR_trace_event_internal(MR_TraceCmdInfo *cmd, MR_bool interactive,
     MR_trace_listing_path_ensure_init();
 
     if (MR_spy_point_cond_problem != NULL) {
+        const char *cond_var_name;
+
         fprintf(MR_mdb_err, "mdb: couldn't evaluate break point condition\n");
         fprintf(MR_mdb_err, "    ");
-        MR_print_spy_cond(MR_mdb_err, MR_spy_point_cond_bad);
+        MR_print_spy_cond(MR_mdb_err, MR_spy_point_cond_bad, &cond_var_name);
         fprintf(MR_mdb_err, ".\n");
-        fprintf(MR_mdb_err, "The error is: %s.\n", MR_spy_point_cond_problem);
+        if (MR_streq(MR_spy_point_cond_problem, "there is no such variable") &&
+            cond_var_name != NULL)
+        {
+            fprintf(MR_mdb_err,
+                "The error is: there is no variable named %s.\n",
+                cond_var_name);
+        } else {
+            fprintf(MR_mdb_err,
+                "The error is: %s.\n", MR_spy_point_cond_problem);
+        }
         MR_spy_point_cond_bad = NULL;
         MR_spy_point_cond_problem = NULL;
     }
diff --git a/trace/mercury_trace_spy.c b/trace/mercury_trace_spy.c
index a59ea8184..6d5a976c8 100644
--- a/trace/mercury_trace_spy.c
+++ b/trace/mercury_trace_spy.c
@@ -1,7 +1,7 @@
 // vim: ts=4 sw=4 expandtab ft=c
 
 // Copyright (C) 1998-2002, 2005-2008, 2011 The University of Melbourne.
-// Copyright (C) 2014-2016, 2018 The Mercury team.
+// Copyright (C) 2014-2016, 2018, 2025 The Mercury team.
 // This file is distributed under the terms specified in COPYING.LIB.
 
 // This file contains code to manage spy points for both
@@ -1076,6 +1076,7 @@ MR_print_spy_point(FILE *fp, int spy_point_num, MR_bool verbose)
     MR_SpyPoint     *point;
     MR_SpyCond      *cond;
     MR_TracePort    port;
+    const char      *ignored_cond_var_name;
 
     point = MR_spy_points[spy_point_num];
     fprintf(fp, "%2d: %1s %-5s %-9s ",
@@ -1157,7 +1158,7 @@ MR_print_spy_point(FILE *fp, int spy_point_num, MR_bool verbose)
             fprintf(fp, "-p ");
         }
 
-        MR_print_spy_cond(fp, cond);
+        MR_print_spy_cond(fp, cond, &ignored_cond_var_name);
         fprintf(fp, "\n");
     }
 
@@ -1216,24 +1217,28 @@ MR_print_spy_point(FILE *fp, int spy_point_num, MR_bool verbose)
 }
 
 void
-MR_print_spy_cond(FILE *fp, MR_SpyCond *cond)
+MR_print_spy_cond(FILE *fp, MR_SpyCond *cond, const char **name)
 {
     switch (cond->MR_cond_var_spec.MR_var_spec_kind) {
         case MR_VAR_SPEC_NUMBER:
             fprintf(fp, "%" MR_INTEGER_LENGTH_MODIFIER "u",
                 cond->MR_cond_var_spec.MR_var_spec_number);
+            *name = NULL;
             break;
 
         case MR_VAR_SPEC_NAME:
-            fprintf(fp, "%s", cond->MR_cond_var_spec.MR_var_spec_name);
+            *name = cond->MR_cond_var_spec.MR_var_spec_name;
+            fprintf(fp, "%s", *name);
             break;
 
         case MR_VAR_SPEC_HELD_NAME:
-            fprintf(fp, "$%s", cond->MR_cond_var_spec.MR_var_spec_name);
+            *name = cond->MR_cond_var_spec.MR_var_spec_name;
+            fprintf(fp, "$%s", *name);
             break;
 
         case MR_VAR_SPEC_ATTRIBUTE:
             fprintf(fp, "!%s", cond->MR_cond_var_spec.MR_var_spec_name);
+            *name = NULL;
             break;
     }
 
diff --git a/trace/mercury_trace_spy.h b/trace/mercury_trace_spy.h
index 025e92d97..f9c23457b 100644
--- a/trace/mercury_trace_spy.h
+++ b/trace/mercury_trace_spy.h
@@ -1,7 +1,7 @@
 // vim: ts=4 sw=4 expandtab ft=c
 
 // Copyright (C) 1998-2001, 2005-2007 The University of Melbourne.
-// Copyright (C) 2016, 2018 The Mercury team.
+// Copyright (C) 2016, 2018, 2025 The Mercury team.
 // This file is distributed under the terms specified in COPYING.LIB.
 
 // This file contains the declarations of the types and functions that
@@ -187,8 +187,11 @@ extern  void            MR_delete_spy_point(int point_table_slot);
 extern  void            MR_print_spy_point(FILE *fp, int i, MR_bool verbose);
 
 // Print the given spy point condition in a user-friendly manner.
+// If the condition involves a named variable, set *name to point to that name.
+// Otherwise, set it to NULL.
 
-extern  void            MR_print_spy_cond(FILE *fp, MR_SpyCond *cond);
+extern  void            MR_print_spy_cond(FILE *fp, MR_SpyCond *cond,
+                            const char **name);
 
 // Print the set of current spy points (including those that are currently
 // disabled) to fp in a format that, when sourced by mdb, recreates those