diff --git a/internal/driver/ioscompanion/companionassets/prepare.sh b/internal/driver/ioscompanion/companionassets/prepare.sh
new file mode 100755
index 0000000..d69c27d
--- /dev/null
+++ b/internal/driver/ioscompanion/companionassets/prepare.sh
@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+#
+# Builds the embeddable simulator companion tarball.
+#
+# Copies the runtime files from a local install, preserving the bin/ and
+# Frameworks/ layout (the binary resolves frameworks through @rpath, so the
+# two directories must stay siblings). Build-time metadata that is never
+# needed at runtime is stripped to keep the embedded payload small. The
+# stripped layout is re-signed ad-hoc and proven to execute before it is
+# packaged.
+#
+# Output: assets/companion-1.1.8.tar.gz next to this script.
+
+set -euo pipefail
+
+# Keep the archiver from emitting AppleDouble (._name) sidecar entries that
+# would otherwise duplicate extended attributes into the payload.
+export COPYFILE_DISABLE=1
+
+VERSION="1.1.8"
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ASSETS_DIR="${SCRIPT_DIR}/assets"
+OUTPUT="${ASSETS_DIR}/companion-${VERSION}.tar.gz"
+
+# Default source is the local formula install. Resolve the symlink so the
+# rsync below copies real files rather than a dangling link.
+SOURCE="${COMPANION_SOURCE:-/opt/homebrew/opt/idb-companion}"
+if [ ! -e "${SOURCE}" ]; then
+  echo "source not found: ${SOURCE}" >&2
+  echo "set COMPANION_SOURCE to the install prefix" >&2
+  exit 1
+fi
+SOURCE="$(cd "${SOURCE}" && pwd -P)"
+
+if [ ! -x "${SOURCE}/bin/idb_companion" ]; then
+  echo "no companion binary at ${SOURCE}/bin/idb_companion" >&2
+  exit 1
+fi
+
+STAGE="$(mktemp -d)"
+PROOF="$(mktemp -d)"
+trap 'rm -rf "${STAGE}" "${PROOF}"' EXIT
+
+echo "staging from ${SOURCE}"
+
+# Copy the runtime layout. -a preserves symlinks (the macOS framework
+# Versions/Current links must survive intact).
+mkdir -p "${STAGE}/bin"
+cp -a "${SOURCE}/bin/idb_companion" "${STAGE}/bin/idb_companion"
+cp -aR "${SOURCE}/Frameworks" "${STAGE}/Frameworks"
+
+# Strip build-time metadata from every framework. The framework binary, its
+# Info.plist, the code signature, and any runtime dylibs are kept; headers and
+# the Swift module/source-info artifacts are not loaded at runtime.
+for framework in "${STAGE}"/Frameworks/*.framework; do
+  version_dir="${framework}/Versions/A"
+  [ -d "${version_dir}" ] || continue
+
+  rm -rf "${version_dir}/Headers" "${version_dir}/PrivateHeaders"
+  rm -rf "${version_dir}/Modules"
+  rm -f "${framework}/Headers" "${framework}/PrivateHeaders" "${framework}/Modules"
+
+  find "${version_dir}" -name '*.swiftmodule' -prune -exec rm -rf {} + 2>/dev/null || true
+  find "${version_dir}" \( -name '*.swiftdoc' -o -name '*.swiftsourceinfo' \) -delete 2>/dev/null || true
+done
+
+# Re-sign each framework and the main binary ad-hoc. Removing files breaks the
+# existing signature seal, which the loader rejects on arm64 macOS.
+for framework in "${STAGE}"/Frameworks/*.framework; do
+  codesign --force --sign - --timestamp=none "${framework}" >/dev/null 2>&1
+done
+codesign --force --sign - --timestamp=none "${STAGE}/bin/idb_companion" >/dev/null 2>&1
+
+# Prove the stripped, re-signed layout still loads and runs. tar stores
+# symlinks as symlinks so the extracted copy mirrors the embedded payload.
+# --version dynamically links every framework and exits zero on success,
+# which fails if a strip or re-sign broke a load command or the seal.
+STRIPPED_BYTES="$(find "${STAGE}" -type f -exec stat -f%z {} + | awk '{sum += $1} END {print sum}')"
+
+PROOF_TAR="${PROOF}/payload.tar.gz"
+tar -czf "${PROOF_TAR}" -C "${STAGE}" .
+tar -xzf "${PROOF_TAR}" -C "${PROOF}"
+
+if ! "${PROOF}/bin/idb_companion" --version >/dev/null 2>&1; then
+  echo "stripped companion failed to execute" >&2
+  exit 1
+fi
+echo "stripped layout executes"
+
+mkdir -p "${ASSETS_DIR}"
+tar -czf "${OUTPUT}" -C "${STAGE}" .
+
+SHA="$(shasum -a 256 "${OUTPUT}" | awk '{print $1}')"
+
+echo "wrote ${OUTPUT}"
+echo "stripped uncompressed size: ${STRIPPED_BYTES} bytes"
+echo "sha256: ${SHA}"