diff --git a/.github/workflows/packer-snapshots.yml b/.github/workflows/packer-snapshots.yml
index 21bf76e4..d96a8da9 100644
--- a/.github/workflows/packer-snapshots.yml
+++ b/.github/workflows/packer-snapshots.yml
@@ -84,8 +84,6 @@ jobs:
 
       - name: Build snapshot
         run: packer build -var-file=packer/auto.pkrvars.json packer/digitalocean.pkr.hcl
-        env:
-          PACKER_LOG: "1"
 
       - name: Cleanup old snapshots
         if: success()
@@ -105,3 +103,53 @@ jobs:
         env:
           DO_API_TOKEN: ${{ secrets.DO_API_TOKEN }}
           AGENT_NAME: ${{ matrix.agent }}
+
+      - name: Submit to DO Marketplace
+        if: success()
+        run: |
+          # Skip if no marketplace app IDs configured
+          if [ -z "$MARKETPLACE_APP_IDS" ]; then
+            echo "No MARKETPLACE_APP_IDS secret — skipping marketplace submission"
+            exit 0
+          fi
+
+          # Look up this agent's app ID from the JSON map
+          APP_ID=$(echo "$MARKETPLACE_APP_IDS" | jq -r --arg a "$AGENT_NAME" '.[$a] // empty')
+          if [ -z "$APP_ID" ]; then
+            echo "No marketplace app ID for agent ${AGENT_NAME} — skipping"
+            exit 0
+          fi
+
+          # Extract snapshot ID from Packer manifest
+          # artifact_id format is "region:snapshot_id" (e.g. "sfo3:12345678")
+          IMG_ID=$(jq '.builds[-1].artifact_id | split(":")[1] | tonumber' packer/manifest.json)
+          if [ -z "$IMG_ID" ] || [ "$IMG_ID" = "null" ]; then
+            echo "Failed to extract snapshot ID from manifest"
+            exit 1
+          fi
+
+          echo "Submitting snapshot ${IMG_ID} for ${AGENT_NAME} (app: ${APP_ID})"
+
+          # PATCH the Vendor API — updates go to "pending" review.
+          # 400 = app already pending/in-review (expected for nightly runs), not an error.
+          HTTP_CODE=$(curl -s -o /tmp/mp-response.json -w "%{http_code}" \
+            -X PATCH \
+            -H "Content-Type: application/json" \
+            -H "Authorization: Bearer ${DO_API_TOKEN}" \
+            -d "$(jq -n \
+              --arg reason "Nightly rebuild — $(date -u '+%Y-%m-%d')" \
+              --argjson imageId "$IMG_ID" \
+              '{reasonForUpdate: $reason, imageId: $imageId}')" \
+            "https://api.digitalocean.com/api/v1/vendor-portal/apps/${APP_ID}")
+
+          case "$HTTP_CODE" in
+            200) echo "Marketplace submission accepted (pending review)" ;;
+            400) echo "App already pending review — skipping (expected for nightly runs)" ;;
+            *)   echo "Marketplace API returned ${HTTP_CODE}:"
+                 cat /tmp/mp-response.json
+                 exit 1 ;;
+          esac
+        env:
+          DO_API_TOKEN: ${{ secrets.DO_API_TOKEN }}
+          AGENT_NAME: ${{ matrix.agent }}
+          MARKETPLACE_APP_IDS: ${{ secrets.MARKETPLACE_APP_IDS }}
diff --git a/packer/digitalocean.pkr.hcl b/packer/digitalocean.pkr.hcl
index acfc2bcd..210f93b4 100644
--- a/packer/digitalocean.pkr.hcl
+++ b/packer/digitalocean.pkr.hcl
@@ -107,10 +107,13 @@ build {
   }
 
   # DO Marketplace: install all security updates and remove DO droplet agent
+  # Uses --force-confold to keep existing config files during upgrades
   provisioner "shell" {
     inline = [
       "apt-get update -y",
-      "apt-get dist-upgrade -y",
+      "apt-get -o Dpkg::Options::='--force-confold' dist-upgrade -y",
+      "apt-get -y autoremove",
+      "apt-get -y autoclean",
       "apt-get purge -y droplet-agent || true",
       "rm -rf /opt/digitalocean",
     ]
@@ -119,22 +122,31 @@ build {
     ]
   }
 
-  # DO Marketplace cleanup — runs last before snapshot.
-  # Based on https://github.com/digitalocean/marketplace-partners/blob/master/scripts/cleanup.sh
-  # Clears secrets, history, logs, and machine-id so each launched droplet
+  # DO Marketplace cleanup — matches digitalocean/marketplace-partners/scripts/90-cleanup.sh
+  # Clears secrets, keys, history, logs, and machine-id so each launched droplet
   # gets a fresh identity. cloud-init re-runs on first boot to re-inject keys.
   provisioner "shell" {
     inline = [
-      # Remove SSH authorized keys (cloud-init re-injects them on first boot)
+      # Ensure /tmp exists with correct permissions
+      "mkdir -p /tmp",
+      "chmod 1777 /tmp",
+
+      # Remove SSH authorized keys (cloud-init re-injects on first boot)
       "rm -f /root/.ssh/authorized_keys",
       "find /home -name authorized_keys -delete",
 
-      # Clear bash history (history -c is bash-only; Packer runs /bin/sh)
+      # Remove SSH host keys (regenerated on first boot)
+      "rm -f /etc/ssh/ssh_host_*",
+      "touch /etc/ssh/revoked_keys",
+      "chmod 600 /etc/ssh/revoked_keys",
+
+      # Clear bash history
       "rm -f /root/.bash_history",
       "find /home -name .bash_history -delete",
 
-      # Purge log files
-      "find /var/log -type f -exec truncate --size 0 {} \\;",
+      # Truncate recent log files and remove archived logs
+      "find /var/log -mtime -1 -type f -exec truncate -s 0 {} \\;",
+      "rm -rf /var/log/*.gz /var/log/*.[0-9] /var/log/*-????????",
 
       # Clear apt cache
       "apt-get clean",
@@ -143,14 +155,21 @@ build {
       # Clear tmp
       "rm -rf /tmp/* /var/tmp/*",
 
+      # Remove cloud-init instance data so it re-runs on first boot
+      "rm -rf /var/lib/cloud/instances/*",
+
       # Remove machine-id so each launched droplet gets a unique one
       "truncate -s 0 /etc/machine-id",
       "rm -f /var/lib/dbus/machine-id",
       "ln -sf /etc/machine-id /var/lib/dbus/machine-id",
 
-      # Reset cloud-init so it runs again on first boot (re-injects SSH keys, hostname, etc.)
+      # Reset cloud-init so it runs again on first boot
       "cloud-init clean --logs",
 
+      # Zero-fill free disk space to reduce snapshot size
+      "dd if=/dev/zero of=/zerofile bs=4096 || true",
+      "rm -f /zerofile",
+
       "sync",
     ]
   }
@@ -165,4 +184,10 @@ build {
       "rm -f /tmp/img_check.sh",
     ]
   }
+
+  # Write Packer manifest for automated Marketplace submission
+  post-processor "manifest" {
+    output     = "packer/manifest.json"
+    strip_path = true
+  }
 }