diff --git a/.gitignore b/.gitignore
index 6bfa213..ef800b7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,7 @@ dist
 .env
 .env.*
 .DS_Store
+
+# Docker prep (generated by scripts/docker-prep.sh)
+.docker-deps/
+package.json.bak
diff --git a/scripts/docker-prep.sh b/scripts/docker-prep.sh
new file mode 100755
index 0000000..f8c53f2
--- /dev/null
+++ b/scripts/docker-prep.sh
@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+# Pack @bytelyst/* tarballs from the sibling common-plat repo for
+# self-contained Docker builds that don't need the Gitea npm registry.
+#
+# Usage:
+#   ./scripts/docker-prep.sh           # pack tarballs + rewrite package.json
+#   ./scripts/docker-prep.sh --restore # undo rewrite
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+REPO_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
+COMMON_PLAT="${REPO_DIR}/../learning_ai_common_plat"
+
+TARBALL_DIR="${REPO_DIR}/.docker-deps"
+
+# ── Restore mode ───────────────────────────────────────────────────
+if [[ "${1:-}" == "--restore" ]]; then
+  echo "Restoring original package.json files..."
+  for bak in $(find "$REPO_DIR" -name "package.json.bak" -not -path "*/node_modules/*"); do
+    mv "$bak" "${bak%.bak}"
+    echo "  Restored ${bak%.bak}"
+  done
+  rm -rf "$TARBALL_DIR"
+  echo "Done."
+  exit 0
+fi
+
+# ── Pack mode ──────────────────────────────────────────────────────
+echo "=== docker-prep: packing @bytelyst/* tarballs ==="
+
+rm -rf "$TARBALL_DIR"
+mkdir -p "$TARBALL_DIR"
+
+# Build all packages first
+echo "Building @bytelyst/* packages..."
+(cd "$COMMON_PLAT" && pnpm -r --filter './packages/**' build)
+
+# Pack each package and build a mapping of name → tarball filename
+# (uses a temp file instead of associative array for bash 3.2 compat)
+TARBALL_MAP_FILE=$(mktemp)
+trap 'rm -f "$TARBALL_MAP_FILE"' EXIT
+
+for pkg_dir in "$COMMON_PLAT"/packages/*/; do
+  pkg_name=$(node -p "require('${pkg_dir}package.json').name" 2>/dev/null || true)
+  if [[ -z "$pkg_name" ]]; then continue; fi
+
+  echo "  Packing $pkg_name..."
+  tarball=$(cd "$pkg_dir" && pnpm pack --pack-destination "$TARBALL_DIR" 2>/dev/null | tail -1)
+  filename=$(basename "$tarball")
+  echo "${pkg_name}=${filename}" >> "$TARBALL_MAP_FILE"
+  echo "    -> $filename"
+done
+
+# ── Rewrite package.json files ─────────────────────────────────────
+echo ""
+echo "Rewriting package.json @bytelyst/* refs to .docker-deps/ tarballs..."
+
+rewrite_package_json() {
+  local pkg_file="$1"
+  local rel_prefix="$2"  # relative path from package.json dir to repo root
+
+  if [[ ! -f "$pkg_file" ]]; then return; fi
+
+  # Backup
+  cp "$pkg_file" "${pkg_file}.bak"
+
+  local tmp="${pkg_file}.tmp"
+  cp "$pkg_file" "$tmp"
+
+  while IFS='=' read -r pkg_name tarball; do
+    [[ -z "$pkg_name" ]] && continue
+    # Replace "^0.1.0" (or any semver/file: ref) with "file:../.docker-deps/<tarball>"
+    sed -i '' "s|\"${pkg_name}\": \"[^\"]*\"|\"${pkg_name}\": \"file:${rel_prefix}.docker-deps/${tarball}\"|g" "$tmp"
+  done < "$TARBALL_MAP_FILE"
+
+  mv "$tmp" "$pkg_file"
+  echo "  Rewrote $pkg_file"
+}
+
+# Backend package.json
+rewrite_package_json "${REPO_DIR}/backend/package.json" "../"
+
+# Web package.json
+rewrite_package_json "${REPO_DIR}/web/package.json" "../"
+
+# ── Inject pnpm.overrides for transitive @bytelyst/* deps ─────────
+# Tarball packages may depend on other @bytelyst/* packages (e.g.
+# @bytelyst/fastify-core → @bytelyst/errors). Without overrides, pnpm
+# tries to fetch them from the npm registry which fails.
+inject_overrides() {
+  local pkg_file="$1"
+  local rel_prefix="$2"
+
+  if [[ ! -f "$pkg_file" ]]; then return; fi
+
+  local overrides=""
+  while IFS='=' read -r pkg_name tarball; do
+    [[ -z "$pkg_name" ]] && continue
+    if [[ -n "$overrides" ]]; then overrides="$overrides, "; fi
+    overrides="$overrides\"${pkg_name}\": \"file:${rel_prefix}.docker-deps/${tarball}\""
+  done < "$TARBALL_MAP_FILE"
+
+  if [[ -n "$overrides" ]]; then
+    node -e "
+      const fs = require('fs');
+      const p = JSON.parse(fs.readFileSync('${pkg_file}', 'utf8'));
+      p.pnpm = p.pnpm || {};
+      p.pnpm.overrides = { ...(p.pnpm.overrides || {}), ...JSON.parse('{${overrides}}') };
+      fs.writeFileSync('${pkg_file}', JSON.stringify(p, null, 2) + '\n');
+    "
+    echo "  Injected pnpm.overrides into $pkg_file"
+  fi
+}
+
+inject_overrides "${REPO_DIR}/backend/package.json" "../"
+inject_overrides "${REPO_DIR}/web/package.json" "../"
+
+echo ""
+echo "Done. Tarballs in $TARBALL_DIR"
+echo ""
+echo "To build Docker images:"
+echo "  docker compose build"
+echo ""
+echo "To restore after build:"
+echo "  ./scripts/docker-prep.sh --restore"