diff --git a/entrypoint.sh b/entrypoint.sh
index cca8a26..4c0cbba 100644
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -87,15 +87,39 @@ if [ "${COMMENT_PR_ARG}" = "true" ]; then
       echo "[slinky] GITHUB_REPOSITORY not set; skipping PR comment."
     else
       BODY_CONTENT="$(cat "${MD_OUT_ARG}")"
-      curl -sS -H "Authorization: Bearer ${GITHUB_TOKEN}" \
+      COMMENT_BODY="<!-- slinky-report -->\n${BODY_CONTENT}"
+
+      # Try to find an existing slinky comment to update
+      COMMENTS_JSON=$(curl -sS -H "Authorization: Bearer ${GITHUB_TOKEN}" \
            -H "Accept: application/vnd.github+json" \
            -H "X-GitHub-Api-Version: 2022-11-28" \
-           -X POST "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR_NUMBER}/comments" \
-           -d "$(printf '{"body": %s}' "$(jq -Rs . <<EOF
-${BODY_CONTENT}
+           "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR_NUMBER}/comments?per_page=100") || COMMENTS_JSON="[]"
+
+      EXISTING_ID=$(printf '%s' "${COMMENTS_JSON}" | jq -r '[.[] | select((.body // "") | contains("<!-- slinky-report -->"))][0].id // empty')
+
+      if [ -n "${EXISTING_ID}" ]; then
+        # Update existing comment
+        curl -sS -H "Authorization: Bearer ${GITHUB_TOKEN}" \
+             -H "Accept: application/vnd.github+json" \
+             -H "X-GitHub-Api-Version: 2022-11-28" \
+             -X PATCH "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/comments/${EXISTING_ID}" \
+             -d "$(printf '{"body": %s}' "$(jq -Rs . <<EOF
+${COMMENT_BODY}
 EOF
 )" )" >/dev/null || true
-      echo "[slinky] Posted PR comment to #${PR_NUMBER}."
+        echo "[slinky] Updated existing PR comment #${EXISTING_ID}."
+      else
+        # Create new comment
+        curl -sS -H "Authorization: Bearer ${GITHUB_TOKEN}" \
+             -H "Accept: application/vnd.github+json" \
+             -H "X-GitHub-Api-Version: 2022-11-28" \
+             -X POST "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR_NUMBER}/comments" \
+             -d "$(printf '{"body": %s}' "$(jq -Rs . <<EOF
+${COMMENT_BODY}
+EOF
+)" )" >/dev/null || true
+        echo "[slinky] Posted PR comment to #${PR_NUMBER}."
+      fi
     fi
   fi
 fi
diff --git a/internal/report/markdown.go b/internal/report/markdown.go
index 3250dda..9d1ac18 100644
--- a/internal/report/markdown.go
+++ b/internal/report/markdown.go
@@ -50,15 +50,30 @@ func WriteMarkdown(path string, results []web.Result, s Summary) (string, error)
 	var buf bytes.Buffer
 	// Title and summary
 	buf.WriteString("## Slinky Test Report\n\n")
-	buf.WriteString(fmt.Sprintf("- **Root**: %s\n", escapeMD(s.RootPath)))
-	buf.WriteString(fmt.Sprintf("- **Started**: %s\n", s.StartedAt.Format("2006-01-02 15:04:05 MST")))
-	buf.WriteString(fmt.Sprintf("- **Finished**: %s\n", s.FinishedAt.Format("2006-01-02 15:04:05 MST")))
-	buf.WriteString(fmt.Sprintf("- **Processed**: %d  •  **OK**: %d  •  **Fail**: %d\n", s.Processed, s.OK, s.Fail))
-	buf.WriteString(fmt.Sprintf("- **Rates**: avg %.1f/s  •  peak %.1f/s  •  low %.1f/s\n", s.AvgRPS, s.PeakRPS, s.LowRPS))
-	if s.JSONPath != "" {
-		base := filepath.Base(s.JSONPath)
-		buf.WriteString(fmt.Sprintf("- **JSON**: %s\n", escapeMD(base)))
+
+	// Optional root
+	if strings.TrimSpace(s.RootPath) != "." && strings.TrimSpace(s.RootPath) != "" && s.RootPath != string(filepath.Separator) {
+		buf.WriteString(fmt.Sprintf("- **Root**: %s\n", escapeMD(s.RootPath)))
 	}
+
+	// Last run and duration
+	buf.WriteString(fmt.Sprintf("- **Last Run**: %s\n", s.StartedAt.Format("2006-01-02 15:04:05 MST")))
+	dur := s.FinishedAt.Sub(s.StartedAt)
+	if dur < 0 {
+		dur = 0
+	}
+	buf.WriteString(fmt.Sprintf("- **Duration**: %s\n", dur.Truncate(time.Millisecond)))
+
+	// Totals
+	buf.WriteString(fmt.Sprintf("- **Total**: %d\n", s.Processed))
+	buf.WriteString(fmt.Sprintf("- **Pass**: %d\n", s.OK))
+	buf.WriteString(fmt.Sprintf("- **Fail**: %d\n", s.Fail))
+
+	// Rates only if non-zero
+	if !(s.AvgRPS == 0 && s.PeakRPS == 0 && s.LowRPS == 0) {
+		buf.WriteString(fmt.Sprintf("- **Rates**: avg %.1f/s  •  peak %.1f/s  •  low %.1f/s\n", s.AvgRPS, s.PeakRPS, s.LowRPS))
+	}
+
 	buf.WriteString("\n")
 
 	// Failures by URL