diff --git a/ralph-loop.sh b/ralph-loop.sh
index 7a82be8..ff12962 100755
--- a/ralph-loop.sh
+++ b/ralph-loop.sh
@@ -37,6 +37,7 @@ SPEC_FILE="PROJECT-SPEC.md"
 AGENT_FILE="AGENT.md"
 BOARD_FILE=""
 LOG_DIR=".ralph-logs"
+SESSION_TS="$(date '+%Y%m%dT%H%M%S')"
 RATE_LIMIT_WAIT=1800
 SESSION_ENDS=""
 REQUIRE_PRO=1
@@ -349,7 +350,7 @@ wait_for_tokens() {
 run_agent() {
   local iteration=$1
   local mode=$2
-  local logfile="$LOG_DIR/iteration-${iteration}.log"
+  local logfile="$LOG_DIR/${SESSION_TS}-iteration-${iteration}.log"
   local prompt=""
 
   if [[ "$mode" == "plan" ]]; then
@@ -489,7 +490,7 @@ echo ""
 
 for i in $(seq 1 "$MAX_ITERATIONS"); do
   run_agent "$i" build
-  logfile="$LOG_DIR/iteration-${i}.log"
+  logfile="$LOG_DIR/${SESSION_TS}-iteration-${i}.log"
 
   status=0; check_output "$logfile" || status=$?