diff --git a/.tangled/workflows/android-apk.yml b/.tangled/workflows/android-apk.yml
index aa5ed24..92621dc 100644
--- a/.tangled/workflows/android-apk.yml
+++ b/.tangled/workflows/android-apk.yml
@@ -34,12 +34,16 @@ dependencies:
     - file
     - which
     - git
+    - jdk
+    - zlib
 
 environment:
   CARGO_TERM_COLOR: "always"
   GLOBAL_CI_INSTALL_NDK: "1"
-  # NDK lands under $HOME in the container workspace home.
+  # NDK + minimal SDK under workspace (ephemeral runner FS).
   ANDROID_NDK_HOME: "/tangled/workspace/.android-ndk-r29"
+  ANDROID_HOME: "/tangled/workspace/.android-sdk"
+  ANDROID_SDK_ROOT: "/tangled/workspace/.android-sdk"
 
 steps:
   - name: "Rust toolchain + android target"
diff --git a/scripts/ci-build-apk.sh b/scripts/ci-build-apk.sh
index ea80e19..e6dc1ec 100755
--- a/scripts/ci-build-apk.sh
+++ b/scripts/ci-build-apk.sh
@@ -10,8 +10,9 @@
 # Env:
 #   GLOBAL_ROOT          checkout root (default: repo root of this script)
 #   ANDROID_NDK_HOME     NDK root (default: $HOME/.local/share/android-ndk-r29)
+#   ANDROID_HOME         SDK root (default: $HOME/.local/share/android-sdk)
 #   GLOBAL_VIDYA_SRC     optional vidya sources (else in-tree vidya/ or $HOME/code/vidya)
-#   GLOBAL_CI_INSTALL_NDK=1  download NDK r29 side-by-side if missing (heavy; Spindle)
+#   GLOBAL_CI_INSTALL_NDK=1  download NDK r29 + minimal SDK (build-tools/platforms) if missing
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -24,9 +25,25 @@ NDK_DEFAULT="${HOME}/.local/share/android-ndk-r29"
 export ANDROID_NDK_HOME="${ANDROID_NDK_HOME:-$NDK_DEFAULT}"
 export ANDROID_NDK_ROOT="$ANDROID_NDK_HOME"
 export ANDROID_HOME="${ANDROID_HOME:-${HOME}/.local/share/android-sdk}"
+export ANDROID_SDK_ROOT="${ANDROID_SDK_ROOT:-$ANDROID_HOME}"
 
 log() { echo "[ci-build-apk] $*" >&2; }
 
+# First matching directory under $1 matching basename glob $2 (no find(1)).
+first_dir() {
+  local base="$1" pattern="$2" d
+  shopt -s nullglob
+  for d in "$base"/$pattern; do
+    if [[ -d "$d" ]]; then
+      shopt -u nullglob
+      printf '%s\n' "$d"
+      return 0
+    fi
+  done
+  shopt -u nullglob
+  return 1
+}
+
 ensure_vidya() {
   local dest="$ROOT/.flake/vidya"
   mkdir -p "$ROOT/.flake"
@@ -78,22 +95,98 @@ ensure_ndk() {
   extract_dir="$(mktemp -d)"
   unzip -q "$zip" -d "$extract_dir"
   # Prefer bash glob over find(1) — Spindle nixery images may omit findutils.
-  local found="" d
-  shopt -s nullglob
-  for d in "$extract_dir"/android-ndk-*; do
-    if [[ -d "$d" ]]; then
-      found="$d"
-      break
-    fi
-  done
-  shopt -u nullglob
-  [[ -n "$found" ]] || { log "NDK extract failed under $extract_dir"; exit 1; }
+  local found
+  found="$(first_dir "$extract_dir" 'android-ndk-*' || true)"
+  [[ -n "${found:-}" ]] || { log "NDK extract failed under $extract_dir"; exit 1; }
   rm -rf "$ANDROID_NDK_HOME"
   mv "$found" "$ANDROID_NDK_HOME"
   rm -rf "$extract_dir"
   log "NDK installed: $ANDROID_NDK_HOME"
 }
 
+# cargo-apk/ndk-build require ANDROID_HOME/{build-tools,platforms}.
+ensure_sdk() {
+  local bt_ok=0 plat_ok=0
+  if [[ -d "$ANDROID_HOME/build-tools" ]]; then
+    if first_dir "$ANDROID_HOME/build-tools" '[0-9]*' >/dev/null; then
+      bt_ok=1
+    fi
+  fi
+  if [[ -d "$ANDROID_HOME/platforms" ]]; then
+    if first_dir "$ANDROID_HOME/platforms" 'android-*' >/dev/null; then
+      plat_ok=1
+    fi
+  fi
+  if [[ "$bt_ok" -eq 1 && "$plat_ok" -eq 1 ]]; then
+    log "SDK ok: $ANDROID_HOME (build-tools + platforms)"
+    return 0
+  fi
+  if [[ "${GLOBAL_CI_INSTALL_NDK:-0}" != "1" ]]; then
+    log "ANDROID_HOME incomplete: $ANDROID_HOME (build-tools=$bt_ok platforms=$plat_ok)"
+    log "Install Android SDK build-tools + platforms, or set GLOBAL_CI_INSTALL_NDK=1."
+    exit 1
+  fi
+
+  log "Downloading minimal Android SDK into $ANDROID_HOME…"
+  mkdir -p "$ANDROID_HOME"
+  local tmp zip found
+
+  if [[ "$bt_ok" -ne 1 ]]; then
+    zip="/tmp/android-build-tools-r34-linux.zip"
+    if [[ ! -f "$zip" ]]; then
+      curl -fsSL -o "$zip" \
+        "https://dl.google.com/android/repository/build-tools_r34-linux.zip"
+    fi
+    tmp="$(mktemp -d)"
+    unzip -q "$zip" -d "$tmp"
+    # Zip layout is typically android-14/ → build-tools/34.0.0
+    found="$(first_dir "$tmp" 'android-*' || first_dir "$tmp" '*' || true)"
+    [[ -n "${found:-}" ]] || { log "build-tools extract failed"; exit 1; }
+    mkdir -p "$ANDROID_HOME/build-tools"
+    rm -rf "$ANDROID_HOME/build-tools/34.0.0"
+    mv "$found" "$ANDROID_HOME/build-tools/34.0.0"
+    rm -rf "$tmp"
+    log "build-tools → $ANDROID_HOME/build-tools/34.0.0"
+  fi
+
+  if [[ "$plat_ok" -ne 1 ]]; then
+    zip="/tmp/android-platform-34.zip"
+    if [[ ! -f "$zip" ]]; then
+      curl -fsSL -o "$zip" \
+        "https://dl.google.com/android/repository/platform-34-ext7_r03.zip"
+    fi
+    tmp="$(mktemp -d)"
+    unzip -q "$zip" -d "$tmp"
+    found="$(first_dir "$tmp" 'android-*' || true)"
+    [[ -n "${found:-}" ]] || { log "platform extract failed"; exit 1; }
+    mkdir -p "$ANDROID_HOME/platforms"
+    rm -rf "$ANDROID_HOME/platforms/android-34"
+    mv "$found" "$ANDROID_HOME/platforms/android-34"
+    rm -rf "$tmp"
+    log "platforms → $ANDROID_HOME/platforms/android-34"
+  fi
+
+  # platform-tools optional for packaging but cargo-apk may probe paths.
+  if [[ ! -d "$ANDROID_HOME/platform-tools" ]]; then
+    zip="/tmp/android-platform-tools-linux.zip"
+    if [[ ! -f "$zip" ]]; then
+      curl -fsSL -o "$zip" \
+        "https://dl.google.com/android/repository/platform-tools_r34.0.5-linux.zip" || true
+    fi
+    if [[ -f "$zip" ]]; then
+      tmp="$(mktemp -d)"
+      unzip -q "$zip" -d "$tmp" || true
+      found="$(first_dir "$tmp" 'platform-tools' || true)"
+      if [[ -n "${found:-}" ]]; then
+        rm -rf "$ANDROID_HOME/platform-tools"
+        mv "$found" "$ANDROID_HOME/platform-tools"
+        log "platform-tools installed"
+      fi
+      rm -rf "$tmp"
+    fi
+  fi
+}
+
 setup_rust_android() {
   local prebuilt="$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64"
   local rust_tc=""
@@ -106,7 +199,7 @@ setup_rust_android() {
     fi
     rust_tc=""
   done
-  export PATH="${rust_tc:+${rust_tc}:}${HOME}/.cargo/bin:${prebuilt}/bin:${ANDROID_HOME}/platform-tools:${PATH}"
+  export PATH="${rust_tc:+${rust_tc}:}${HOME}/.cargo/bin:${prebuilt}/bin:${ANDROID_HOME}/build-tools/34.0.0:${ANDROID_HOME}/platform-tools:${PATH}"
   export CC_x86_64_linux_android="${CC_x86_64_linux_android:-x86_64-linux-android28-clang}"
   export CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER="$CC_x86_64_linux_android"
   export AR_x86_64_linux_android="${AR_x86_64_linux_android:-llvm-ar}"
@@ -124,6 +217,7 @@ setup_rust_android() {
 build() {
   ensure_vidya
   ensure_ndk
+  ensure_sdk
   setup_rust_android
   log "cargo apk build --target x86_64-linux-android --no-default-features"
   (
diff --git a/test/ci_apk_workflow_test.sh b/test/ci_apk_workflow_test.sh
index bf5b104..cf828d0 100755
--- a/test/ci_apk_workflow_test.sh
+++ b/test/ci_apk_workflow_test.sh
@@ -37,6 +37,9 @@ check "script tolerates cargo-apk panic" grep -q 'cargo apk build' "$SCRIPT"
 # Spindle nixery may omit findutils; NDK extract must not require bare find(1).
 check "script NDK extract avoids find(1)" bash -c "! grep -E '(^|[^[:alnum:]_])find ' '$SCRIPT'"
 check "workflow includes findutils (belt)" grep -q 'findutils' "$WF"
+check "script bootstraps SDK build-tools" grep -q 'build-tools_r34' "$SCRIPT"
+check "script bootstraps platform android-34" grep -q 'platform-34' "$SCRIPT"
+check "workflow sets ANDROID_HOME" grep -q 'ANDROID_HOME' "$WF"
 
 # If APK present (after a real build), validate it is a non-empty APK/ZIP.
 if [[ -f "$APK_REL" ]]; then