diff --git a/include/noun/trace.h b/include/noun/trace.h
index 0654862d0..555479f14 100644
--- a/include/noun/trace.h
+++ b/include/noun/trace.h
@@ -86,7 +86,7 @@
     /* u3t_trace_open(): opens the path for writing tracing information.
     */
       void
-      u3t_trace_open(c3_c*);
+      u3t_trace_open();
 
     /* u3t_trace_close(): closes the trace file. optional.
     */
diff --git a/include/vere/vere.h b/include/vere/vere.h
index 712086403..79b4ee146 100644
--- a/include/vere/vere.h
+++ b/include/vere/vere.h
@@ -583,7 +583,7 @@
         c3_c*   gen_c;                      //  -G, czar generator
         c3_o    gab;                        //  -g, test garbage collection
         c3_c*   dns_c;                      //  -H, ames bootstrap domain
-        c3_c*   json_file_c;                //  -j, json trace
+        c3_o    tra;                        //  -j, json trace
         c3_w    kno_w;                      //  -K, kernel version
         c3_c*   key_c;                      //  -k, private key file
         c3_o    net;                        //  -L, local-only networking
diff --git a/noun/trace.c b/noun/trace.c
index cea9caccf..7eb8e7179 100644
--- a/noun/trace.c
+++ b/noun/trace.c
@@ -3,7 +3,10 @@
 ** This file is in the public domain.
 */
 #include "all.h"
+#include "vere/vere.h"
 #include <pthread.h>
+#include <time.h>
+#include <sys/stat.h>
 
 static c3_o _ct_lop_o;
 
@@ -300,14 +303,25 @@ u3t_flee(void)
 
 static FILE* trace_file_u = NULL;
 static int nock_pid_i = 0;
+static int trace_counter;
 
 /*  u3t_trace_open(): opens a trace file and writes the preamble.
 */
 void
-u3t_trace_open(c3_c* trace_file_name)
+u3t_trace_open()
 {
-  printf("trace: tracing to %s\n", trace_file_name);
-  trace_file_u = fopen(trace_file_name, "w");
+
+  c3_c fil_c[2048];
+  snprintf(fil_c, 2048, "%s/.urb/put/trace", u3_Host.dir_c);
+
+  struct stat st;
+  if ( -1 == stat(fil_c, &st) ) {
+    mkdir(fil_c, 0700);
+  }
+
+  snprintf(fil_c, 2048, "%s/%ld.json", fil_c, time(NULL));
+
+  trace_file_u = fopen(fil_c, "w");
   nock_pid_i = (int)getpid();
   fprintf(trace_file_u, "[ ");
 
@@ -335,6 +349,7 @@ u3t_trace_open(c3_c* trace_file_name)
           "{\"name\": \"thread_sort_index\", \"ph\": \"M\", \"pid\": %d, "
           "\"tid\": 2, \"args\": {\"sort_index\": 2}},\n",
           nock_pid_i);
+  trace_counter = 5;
 }
 
 /*  u3t_trace_close(): closes a trace file. optional.
@@ -440,6 +455,12 @@ u3t_nock_trace_pop()
   if (!trace_file_u)
     return;
 
+  if ( trace_counter >= 100000 ) {
+    u3t_trace_close();
+    u3t_trace_open();
+  }
+
+
   u3_noun trace  = u3R->pro.trace;
   u3R->pro.trace = u3k(u3t(trace));
 
@@ -462,6 +483,7 @@ u3t_nock_trace_pop()
             duration);
 
     free(name);
+    trace_counter++;
   }
 
   u3z(trace);
@@ -482,6 +504,7 @@ u3t_event_trace(const c3_c* name, c3_c type)
           type,
           nock_pid_i,
           u3t_trace_time());
+  trace_counter++;
 }
 
 extern FILE*
diff --git a/vere/main.c b/vere/main.c
index ac3e05435..f4c962b3d 100644
--- a/vere/main.c
+++ b/vere/main.c
@@ -83,6 +83,7 @@ _main_getopt(c3_i argc, c3_c** argv)
   u3_Host.ops_u.qui = c3n;
   u3_Host.ops_u.rep = c3n;
   u3_Host.ops_u.tex = c3n;
+  u3_Host.ops_u.tra = c3n;
   u3_Host.ops_u.veb = c3n;
   u3_Host.ops_u.kno_w = DefaultKernel;
 
@@ -91,7 +92,7 @@ _main_getopt(c3_i argc, c3_c** argv)
   u3_Host.ops_u.nam_c = 0;
 
   while ( -1 != (ch_i=getopt(argc, argv,
-                 "G:B:K:A:H:w:u:j:e:E:f:F:k:m:p:LabcCdgqstvxPDRS")) ) {
+                 "G:B:K:A:H:w:u:e:E:f:F:k:m:p:LjabcCdgqstvxPDRS")) ) {
 
     switch ( ch_i ) {
       case 'B': {
@@ -131,10 +132,6 @@ _main_getopt(c3_i argc, c3_c** argv)
         u3_Host.ops_u.url_c = strdup(optarg);
         break;
       }
-      case 'j': {
-        u3_Host.ops_u.json_file_c = strdup(optarg);
-        break;
-      }
       case 'x': {
         u3_Host.ops_u.tex = c3y;
         break;
@@ -170,6 +167,7 @@ _main_getopt(c3_i argc, c3_c** argv)
         return c3y;
       }
       case 'L': { u3_Host.ops_u.net = c3n; break; }
+      case 'j': { u3_Host.ops_u.tra = c3y; break; }
       case 'a': { u3_Host.ops_u.abo = c3y; break; }
       case 'b': { u3_Host.ops_u.bat = c3y; break; }
       case 'c': { u3_Host.ops_u.nuu = c3y; break; }
@@ -656,9 +654,9 @@ main(c3_i   argc,
 
       /*  Set tracing flag
       */
-      if ( u3_Host.ops_u.json_file_c ) {
+      if ( _(u3_Host.ops_u.tra) ) {
         u3C.wag_w |= u3o_trace;
-        u3t_trace_open(u3_Host.ops_u.json_file_c);
+        u3t_trace_open();
       }
     }
     u3m_boot(u3_Host.ops_u.nuu,