commit 6a7c85dc260d92b90e22c41cd2624411affc69ca
Author: sssnake <sssnake@seteclabs.io>
Date:   Tue Mar 31 07:18:31 2026 -0700

    BuildChain v1.0.0 — on-device Android build toolchain
    
    System-level KernelSU module: aapt2/aidl/zipalign (API 35), BusyBox,
    platform-tools, all as static arm64 binaries in the Android framework.
    
    Termux integration for Java/Kotlin/Gradle/Python via pkg.
    CLI tools: buildchain, bc-build, bc-sign.
    WebUI on :8089 for toolchain management.
    
    Turns any Android phone into a native compilation powerhouse.

diff --git a/META-INF/com/google/android/update-binary b/META-INF/com/google/android/update-binary
new file mode 100755
index 0000000..f3726fe
--- /dev/null
+++ b/META-INF/com/google/android/update-binary
@@ -0,0 +1,25 @@
+#!/sbin/sh
+umask 022
+OUTFD=$2
+ZIPFILE=$3
+ui_print() { echo "$1"; }
+mount /data 2>/dev/null
+[ -f /data/adb/magisk/util_functions.sh ] || { ui_print "Requires KernelSU-Next"; exit 1; }
+. /data/adb/magisk/util_functions.sh
+[ $MAGISK_VER_CODE -lt 20400 ] && { ui_print "Requires KernelSU-Next"; exit 1; }
+setup_flashable
+mount_partitions
+api_level_arch_detect
+MODID=buildchain
+MODPATH=$MOUNTPATH/$MODID
+ui_print "- Extracting BuildChain"
+unzip -o "$ZIPFILE" -x 'META-INF/*' -d $MODPATH >&2
+set_perm_recursive $MODPATH 0 0 0755 0644
+set_perm_recursive $MODPATH/tools 0 2000 0755 0755
+set_perm_recursive $MODPATH/scripts 0 2000 0755 0755
+set_perm $MODPATH/service.sh 0 0 0755
+set_perm $MODPATH/post-fs-data.sh 0 0 0755
+set_perm $MODPATH/uninstall.sh 0 0 0755
+ui_print "- BuildChain installed"
+ui_print "- Reboot, then run: buildchain setup"
+ui_print "- WebUI at http://localhost:8089"
diff --git a/META-INF/com/google/android/updater-script b/META-INF/com/google/android/updater-script
new file mode 100644
index 0000000..11d5c96
--- /dev/null
+++ b/META-INF/com/google/android/updater-script
@@ -0,0 +1 @@
+#MAGISK
diff --git a/module.prop b/module.prop
new file mode 100644
index 0000000..5db013d
--- /dev/null
+++ b/module.prop
@@ -0,0 +1,6 @@
+id=buildchain
+name=BuildChain
+version=v1.0.0
+versionCode=1
+author=snake
+description=On-device Android build toolchain. aapt2/aidl/zipalign (API 35), BusyBox, Python, Java, Kotlin, Gradle via Termux. Turns any phone into a native compiler. WebUI for toolchain management.
diff --git a/post-fs-data.sh b/post-fs-data.sh
new file mode 100755
index 0000000..72446c4
--- /dev/null
+++ b/post-fs-data.sh
@@ -0,0 +1,26 @@
+#!/system/bin/sh
+# BuildChain — early boot: install busybox applets system-wide, set up paths
+MODDIR=${0%/*}
+CONFIG_DIR="/data/adb/buildchain"
+
+mkdir -p "$CONFIG_DIR"
+echo "$MODDIR" > "$CONFIG_DIR/moddir"
+
+# Install busybox applets to /system/xbin via module overlay
+XBIN="$MODDIR/system/xbin"
+mkdir -p "$XBIN"
+
+if [ -f "$MODDIR/tools/busybox" ]; then
+  cp "$MODDIR/tools/busybox" "$XBIN/busybox"
+  chmod 0755 "$XBIN/busybox"
+
+  # Create symlinks for all busybox applets
+  "$XBIN/busybox" --list 2>/dev/null | while read applet; do
+    [ "$applet" = "busybox" ] && continue
+    # Don't override core Android binaries
+    case "$applet" in
+      sh|ls|cat|cp|mv|rm|mkdir|chmod|chown|mount|umount|reboot|ps|kill|ln|df|du) continue ;;
+    esac
+    ln -sf busybox "$XBIN/$applet" 2>/dev/null
+  done
+fi
diff --git a/scripts/bc-build b/scripts/bc-build
new file mode 100755
index 0000000..2f7b98a
--- /dev/null
+++ b/scripts/bc-build
@@ -0,0 +1,168 @@
+#!/system/bin/sh
+# bc-build — compile Android project from source on-device
+# Supports: single Java/Kotlin file, Gradle project, or raw aapt2+javac+d8 pipeline
+#
+# Usage:
+#   bc-build <file.java>              Compile single Java file to APK
+#   bc-build <file.kt>                Compile single Kotlin file to APK
+#   bc-build <project_dir>            Run gradle assembleDebug
+#   bc-build --raw <src_dir> <out>    Manual aapt2+javac+d8 pipeline
+
+CONFIG_DIR="/data/adb/buildchain"
+MODDIR=$(cat "$CONFIG_DIR/moddir" 2>/dev/null)
+TOOLS="$MODDIR/tools"
+AAPT2="$TOOLS/build-tools/aapt2"
+AIDL="$TOOLS/build-tools/aidl"
+ZIPALIGN="$TOOLS/build-tools/zipalign"
+TBIN="/data/data/com.termux/files/usr/bin"
+ANDROID_JAR="/data/data/com.termux/files/home/android-sdk/platforms/android-35/android.jar"
+
+# Fallback android.jar location
+[ ! -f "$ANDROID_JAR" ] && ANDROID_JAR="/system/framework/framework.jar"
+
+die() { echo "ERROR: $1"; exit 1; }
+
+build_single_java() {
+  local src="$1"
+  local name=$(basename "$src" .java)
+  local outdir="${2:-./build}"
+
+  echo "=== Building $name.java ==="
+  mkdir -p "$outdir/classes" "$outdir/dex" "$outdir/apk"
+
+  echo "[1/5] Compiling Java..."
+  "$TBIN/javac" -source 11 -target 11 -cp "$ANDROID_JAR" -d "$outdir/classes" "$src" || die "javac failed"
+
+  echo "[2/5] Converting to DEX..."
+  "$TBIN/d8" --min-api 28 --output "$outdir/dex/" "$outdir/classes"/*.class 2>/dev/null \
+    || "$TBIN/java" -jar "$TBIN/../share/d8/d8.jar" --min-api 28 --output "$outdir/dex/" "$outdir/classes"/*.class \
+    || die "d8/dex conversion failed"
+
+  echo "[3/5] Packaging APK..."
+  # Create minimal AndroidManifest.xml
+  cat > "$outdir/AndroidManifest.xml" << MANIFEST
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.buildchain.$name">
+    <application android:label="$name">
+        <activity android:name=".$name" android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>
+MANIFEST
+
+  "$AAPT2" link -o "$outdir/apk/$name.unsigned.apk" \
+    --manifest "$outdir/AndroidManifest.xml" \
+    -I "$ANDROID_JAR" 2>/dev/null || die "aapt2 link failed"
+
+  # Add DEX to APK
+  cd "$outdir/dex" && zip -u "../apk/$name.unsigned.apk" classes.dex 2>/dev/null && cd - >/dev/null
+
+  echo "[4/5] Aligning..."
+  "$ZIPALIGN" -f 4 "$outdir/apk/$name.unsigned.apk" "$outdir/apk/$name.aligned.apk" || die "zipalign failed"
+
+  echo "[5/5] Signing..."
+  bc-sign "$outdir/apk/$name.aligned.apk" "$outdir/$name.apk"
+
+  echo ""
+  echo "Output: $outdir/$name.apk"
+  ls -la "$outdir/$name.apk" 2>/dev/null
+}
+
+build_single_kotlin() {
+  local src="$1"
+  local name=$(basename "$src" .kt)
+  local outdir="${2:-./build}"
+
+  echo "=== Building $name.kt ==="
+  mkdir -p "$outdir/classes" "$outdir/dex" "$outdir/apk"
+
+  echo "[1/5] Compiling Kotlin..."
+  "$TBIN/kotlinc" -cp "$ANDROID_JAR" -d "$outdir/classes" "$src" || die "kotlinc failed"
+
+  echo "[2/5] Converting to DEX..."
+  find "$outdir/classes" -name "*.class" | xargs "$TBIN/d8" --min-api 28 --output "$outdir/dex/" 2>/dev/null \
+    || die "d8 failed"
+
+  echo "[3/5] Packaging..."
+  cat > "$outdir/AndroidManifest.xml" << MANIFEST
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.buildchain.$name">
+    <application android:label="$name"/>
+</manifest>
+MANIFEST
+
+  "$AAPT2" link -o "$outdir/apk/$name.unsigned.apk" \
+    --manifest "$outdir/AndroidManifest.xml" \
+    -I "$ANDROID_JAR" 2>/dev/null || die "aapt2 link failed"
+
+  cd "$outdir/dex" && zip -u "../apk/$name.unsigned.apk" classes.dex 2>/dev/null && cd - >/dev/null
+
+  echo "[4/5] Aligning..."
+  "$ZIPALIGN" -f 4 "$outdir/apk/$name.unsigned.apk" "$outdir/apk/$name.aligned.apk"
+
+  echo "[5/5] Signing..."
+  bc-sign "$outdir/apk/$name.aligned.apk" "$outdir/$name.apk"
+
+  echo ""
+  echo "Output: $outdir/$name.apk"
+}
+
+build_gradle_project() {
+  local projdir="$1"
+  echo "=== Building Gradle project: $projdir ==="
+
+  if [ ! -f "$projdir/build.gradle" ] && [ ! -f "$projdir/build.gradle.kts" ]; then
+    die "No build.gradle found in $projdir"
+  fi
+
+  cd "$projdir"
+
+  # Set ANDROID_HOME for Gradle
+  export ANDROID_HOME="/data/data/com.termux/files/home/android-sdk"
+  export ANDROID_SDK_ROOT="$ANDROID_HOME"
+
+  if [ -f "./gradlew" ]; then
+    chmod +x ./gradlew
+    ./gradlew assembleDebug || die "Gradle build failed"
+  elif command -v gradle >/dev/null 2>&1; then
+    gradle assembleDebug || die "Gradle build failed"
+  else
+    die "No gradlew and gradle not installed. Run: buildchain setup"
+  fi
+
+  echo ""
+  echo "Output APKs:"
+  find . -name "*.apk" -path "*/build/outputs/*" 2>/dev/null
+}
+
+# Main
+case "$1" in
+  --help|-h|"")
+    echo "bc-build — compile Android projects on-device"
+    echo ""
+    echo "Usage:"
+    echo "  bc-build MyApp.java           Compile Java to APK"
+    echo "  bc-build MyApp.kt             Compile Kotlin to APK"
+    echo "  bc-build ./my-project/        Run Gradle assembleDebug"
+    echo "  bc-build MyApp.java ./out/    Specify output directory"
+    ;;
+  *.java)
+    build_single_java "$1" "$2"
+    ;;
+  *.kt)
+    build_single_kotlin "$1" "$2"
+    ;;
+  *)
+    if [ -d "$1" ]; then
+      build_gradle_project "$1"
+    else
+      die "Unknown input: $1 (expected .java, .kt, or directory)"
+    fi
+    ;;
+esac
diff --git a/scripts/bc-sign b/scripts/bc-sign
new file mode 100755
index 0000000..fdca441
--- /dev/null
+++ b/scripts/bc-sign
@@ -0,0 +1,83 @@
+#!/system/bin/sh
+# bc-sign — sign APKs with debug or release keystore
+# Usage: bc-sign <input.apk> [output.apk] [--release keystore.jks]
+
+CONFIG_DIR="/data/adb/buildchain"
+TBIN="/data/data/com.termux/files/usr/bin"
+DEBUG_KS="$CONFIG_DIR/debug.keystore"
+DEBUG_PASS="android"
+DEBUG_ALIAS="androiddebugkey"
+
+die() { echo "ERROR: $1"; exit 1; }
+
+# Create debug keystore if it doesn't exist
+ensure_debug_keystore() {
+  if [ ! -f "$DEBUG_KS" ]; then
+    echo "Creating debug keystore..."
+    "$TBIN/keytool" -genkey -v \
+      -keystore "$DEBUG_KS" \
+      -storepass "$DEBUG_PASS" \
+      -alias "$DEBUG_ALIAS" \
+      -keypass "$DEBUG_PASS" \
+      -keyalg RSA -keysize 2048 -validity 10000 \
+      -dname "CN=Android Debug,O=Android,C=US" 2>/dev/null || die "keytool failed — is Java installed? Run: buildchain setup"
+  fi
+}
+
+INPUT="$1"
+OUTPUT="${2:-$(echo "$INPUT" | sed 's/\.unsigned\.apk$/.apk/' | sed 's/\.aligned\.apk$/.apk/')}"
+
+[ -z "$INPUT" ] && { echo "Usage: bc-sign <input.apk> [output.apk] [--release keystore.jks]"; exit 1; }
+[ ! -f "$INPUT" ] && die "File not found: $INPUT"
+
+# Check for release signing
+if [ "$3" = "--release" ] && [ -n "$4" ]; then
+  KEYSTORE="$4"
+  [ ! -f "$KEYSTORE" ] && die "Keystore not found: $KEYSTORE"
+  echo "Signing with release key: $KEYSTORE"
+  read -p "Keystore password: " KS_PASS
+  read -p "Key alias: " KS_ALIAS
+  read -p "Key password: " KEY_PASS
+
+  "$TBIN/apksigner" sign \
+    --ks "$KEYSTORE" \
+    --ks-pass "pass:$KS_PASS" \
+    --ks-key-alias "$KS_ALIAS" \
+    --key-pass "pass:$KEY_PASS" \
+    --v1-signing-enabled true \
+    --v2-signing-enabled true \
+    --v3-signing-enabled true \
+    --out "$OUTPUT" \
+    "$INPUT" || die "apksigner failed"
+else
+  # Debug sign
+  ensure_debug_keystore
+
+  # Try apksigner first (from SDK), fall back to jarsigner
+  if command -v apksigner >/dev/null 2>&1 || [ -f "$TBIN/apksigner" ]; then
+    SIGNER=$(command -v apksigner 2>/dev/null || echo "$TBIN/apksigner")
+    "$SIGNER" sign \
+      --ks "$DEBUG_KS" \
+      --ks-pass "pass:$DEBUG_PASS" \
+      --ks-key-alias "$DEBUG_ALIAS" \
+      --key-pass "pass:$DEBUG_PASS" \
+      --out "$OUTPUT" \
+      "$INPUT" 2>/dev/null && echo "Signed (apksigner): $OUTPUT" && exit 0
+  fi
+
+  # Fallback to jarsigner
+  if [ -f "$TBIN/jarsigner" ]; then
+    cp "$INPUT" "$OUTPUT" 2>/dev/null
+    "$TBIN/jarsigner" \
+      -keystore "$DEBUG_KS" \
+      -storepass "$DEBUG_PASS" \
+      -keypass "$DEBUG_PASS" \
+      -signedjar "$OUTPUT" \
+      "$INPUT" \
+      "$DEBUG_ALIAS" 2>/dev/null && echo "Signed (jarsigner): $OUTPUT" && exit 0
+  fi
+
+  die "No signing tool found. Install Java: buildchain setup"
+fi
+
+echo "Signed: $OUTPUT"
diff --git a/scripts/buildchain b/scripts/buildchain
new file mode 100755
index 0000000..f0c5af8
--- /dev/null
+++ b/scripts/buildchain
@@ -0,0 +1,164 @@
+#!/system/bin/sh
+# BuildChain — main CLI tool
+# Usage: buildchain <command> [args]
+
+CONFIG_DIR="/data/adb/buildchain"
+MODDIR=$(cat "$CONFIG_DIR/moddir" 2>/dev/null)
+TOOLS="$MODDIR/tools"
+VERSION="1.0.0"
+
+usage() {
+  echo "BuildChain v$VERSION — On-device Android build toolchain"
+  echo ""
+  echo "Usage: buildchain <command>"
+  echo ""
+  echo "Commands:"
+  echo "  status      Show installed toolchain components"
+  echo "  setup       Install Java, Python, Kotlin, Gradle via Termux"
+  echo "  env         Print current build environment"
+  echo "  paths       Show all tool paths"
+  echo "  test        Test all build tools"
+  echo "  version     Show version info"
+  echo ""
+  echo "Build helpers:"
+  echo "  bc-build    Compile an Android project"
+  echo "  bc-sign     Sign an APK with debug or release key"
+  echo ""
+  echo "WebUI: http://localhost:8089"
+}
+
+cmd_status() {
+  echo "=== BuildChain Status ==="
+  echo ""
+
+  echo "[Build Tools — API 35]"
+  for tool in aapt aapt2 aidl dexdump zipalign split-select; do
+    local path="$TOOLS/build-tools/$tool"
+    if [ -f "$path" ]; then
+      echo "  [OK] $tool"
+    else
+      echo "  [--] $tool (missing)"
+    fi
+  done
+
+  echo ""
+  echo "[Platform Tools]"
+  for tool in adb fastboot sqlite3 e2fsdroid etc1tool mke2fs make_f2fs sload_f2fs; do
+    local path="$TOOLS/platform-tools/$tool"
+    if [ -f "$path" ]; then
+      echo "  [OK] $tool"
+    else
+      echo "  [--] $tool (missing)"
+    fi
+  done
+
+  echo ""
+  echo "[BusyBox]"
+  if [ -f "$TOOLS/busybox" ]; then
+    local applets=$("$TOOLS/busybox" --list 2>/dev/null | wc -l)
+    echo "  [OK] busybox ($applets applets)"
+  else
+    echo "  [--] busybox (missing)"
+  fi
+
+  echo ""
+  echo "[Termux Packages]"
+  local tbin="/data/data/com.termux/files/usr/bin"
+  for pkg in java javac python3 kotlin kotlinc gradle git cmake make gcc g++ clang; do
+    if [ -f "$tbin/$pkg" ]; then
+      echo "  [OK] $pkg"
+    else
+      echo "  [--] $pkg (run: buildchain setup)"
+    fi
+  done
+
+  echo ""
+  echo "[Android Environment]"
+  echo "  Device:  $(getprop ro.product.model)"
+  echo "  Android: $(getprop ro.build.version.release) (API $(getprop ro.build.version.sdk))"
+  echo "  Arch:    $(uname -m)"
+  echo "  Kernel:  $(uname -r)"
+}
+
+cmd_env() {
+  [ -f "$CONFIG_DIR/env.sh" ] && cat "$CONFIG_DIR/env.sh" || echo "Environment not configured. Run: buildchain setup"
+}
+
+cmd_paths() {
+  echo "=== Tool Paths ==="
+  echo "Build tools:    $TOOLS/build-tools/"
+  echo "Platform tools: $TOOLS/platform-tools/"
+  echo "BusyBox:        $TOOLS/busybox"
+  echo "Config:         $CONFIG_DIR/"
+  echo "Module:         $MODDIR"
+  echo ""
+  echo "=== Resolved Binaries ==="
+  for tool in aapt2 aidl zipalign java javac python3 kotlinc gradle git make cmake clang busybox; do
+    local p=$(which "$tool" 2>/dev/null)
+    [ -n "$p" ] && echo "  $tool -> $p" || echo "  $tool -> (not found)"
+  done
+}
+
+cmd_test() {
+  echo "=== Testing Build Tools ==="
+  echo ""
+
+  echo "aapt2:"
+  "$TOOLS/build-tools/aapt2" version 2>&1 && echo "  PASS" || echo "  FAIL"
+  echo ""
+
+  echo "aidl:"
+  "$TOOLS/build-tools/aidl" --version 2>&1 && echo "  PASS" || echo "  FAIL"
+  echo ""
+
+  echo "zipalign:"
+  "$TOOLS/build-tools/zipalign" 2>&1 | head -1 && echo "  PASS" || echo "  FAIL"
+  echo ""
+
+  echo "dexdump:"
+  "$TOOLS/build-tools/dexdump" 2>&1 | head -1 && echo "  PASS" || echo "  FAIL"
+  echo ""
+
+  echo "busybox:"
+  "$TOOLS/busybox" --help 2>&1 | head -1 && echo "  PASS" || echo "  FAIL"
+  echo ""
+
+  # Test Termux tools if available
+  local tbin="/data/data/com.termux/files/usr/bin"
+  if [ -f "$tbin/java" ]; then
+    echo "java:"
+    "$tbin/java" -version 2>&1 | head -1
+    echo ""
+  fi
+  if [ -f "$tbin/python3" ]; then
+    echo "python:"
+    "$tbin/python3" --version 2>&1
+    echo ""
+  fi
+  if [ -f "$tbin/kotlinc" ]; then
+    echo "kotlin:"
+    "$tbin/kotlinc" -version 2>&1 | head -1
+    echo ""
+  fi
+  if [ -f "$tbin/gradle" ]; then
+    echo "gradle:"
+    "$tbin/gradle" --version 2>&1 | grep "Gradle " | head -1
+    echo ""
+  fi
+}
+
+cmd_version() {
+  echo "BuildChain v$VERSION"
+  echo "Build tools: API 35 (35.0.2)"
+  echo "Target: $(getprop ro.product.model) / Android $(getprop ro.build.version.release)"
+}
+
+case "$1" in
+  status)  cmd_status ;;
+  setup)   sh "$MODDIR/scripts/buildchain-setup" ;;
+  env)     cmd_env ;;
+  paths)   cmd_paths ;;
+  test)    cmd_test ;;
+  version) cmd_version ;;
+  *)       usage ;;
+esac
diff --git a/scripts/buildchain-setup b/scripts/buildchain-setup
new file mode 100755
index 0000000..7dff9e8
--- /dev/null
+++ b/scripts/buildchain-setup
@@ -0,0 +1,91 @@
+#!/system/bin/sh
+# BuildChain Setup — installs Java, Python, Kotlin, Gradle, and dev tools via Termux
+# Must be run from within Termux (or any shell with access to pkg/apt)
+
+TERMUX_PREFIX="/data/data/com.termux/files/usr"
+TERMUX_BIN="$TERMUX_PREFIX/bin"
+
+echo "=== BuildChain Setup ==="
+echo ""
+
+# Check if we're in a Termux-capable environment
+if [ ! -f "$TERMUX_BIN/pkg" ] && ! command -v pkg >/dev/null 2>&1; then
+  echo "ERROR: Termux pkg not found."
+  echo "This script must be run inside Termux or after Termux is installed."
+  echo ""
+  echo "Install Termux from F-Droid or GitHub, open it once, then run this again."
+  exit 1
+fi
+
+PKG="pkg"
+command -v pkg >/dev/null 2>&1 || PKG="$TERMUX_BIN/pkg"
+
+echo "[1/7] Updating package database..."
+$PKG update -y 2>&1 | tail -3
+
+echo ""
+echo "[2/7] Installing Java (OpenJDK 21)..."
+$PKG install -y openjdk-21 2>&1 | tail -3
+echo "  $(java -version 2>&1 | head -1)"
+
+echo ""
+echo "[3/7] Installing Python..."
+$PKG install -y python 2>&1 | tail -3
+echo "  $(python3 --version 2>&1)"
+
+echo ""
+echo "[4/7] Installing Kotlin..."
+$PKG install -y kotlin 2>&1 | tail -3
+echo "  $(kotlinc -version 2>&1 | head -1)"
+
+echo ""
+echo "[5/7] Installing Gradle..."
+$PKG install -y gradle 2>&1 | tail -3
+echo "  $(gradle --version 2>&1 | grep 'Gradle ' | head -1)"
+
+echo ""
+echo "[6/7] Installing build essentials (git, cmake, make, clang, ndk tools)..."
+$PKG install -y git cmake make clang ndk-sysroot binutils 2>&1 | tail -3
+
+echo ""
+echo "[7/7] Installing extra tools (curl, wget, zip, unzip, tar, openssh, jq)..."
+$PKG install -y curl wget zip unzip tar openssh jq 2>&1 | tail -3
+
+echo ""
+echo "=== Setting up Android SDK structure ==="
+ANDROID_HOME="/data/data/com.termux/files/home/android-sdk"
+mkdir -p "$ANDROID_HOME/build-tools/35.0.2"
+mkdir -p "$ANDROID_HOME/platform-tools"
+
+# Symlink our build tools into the SDK structure so Gradle/AGP finds them
+MODDIR=$(cat /data/adb/buildchain/moddir 2>/dev/null)
+if [ -n "$MODDIR" ]; then
+  for tool in aapt aapt2 aidl dexdump zipalign split-select; do
+    ln -sf "$MODDIR/tools/build-tools/$tool" "$ANDROID_HOME/build-tools/35.0.2/$tool" 2>/dev/null
+  done
+  for tool in adb fastboot sqlite3; do
+    ln -sf "$MODDIR/tools/platform-tools/$tool" "$ANDROID_HOME/platform-tools/$tool" 2>/dev/null
+  done
+  echo "  SDK structure created at $ANDROID_HOME"
+fi
+
+echo ""
+echo "=== Setup Complete ==="
+echo ""
+echo "Installed:"
+echo "  Java:    $(java -version 2>&1 | head -1)"
+echo "  Python:  $(python3 --version 2>&1)"
+echo "  Kotlin:  $(kotlinc -version 2>&1 | head -1)"
+echo "  Gradle:  $(gradle --version 2>&1 | grep 'Gradle ' | head -1)"
+echo "  Git:     $(git --version 2>&1)"
+echo "  CMake:   $(cmake --version 2>&1 | head -1)"
+echo "  Clang:   $(clang --version 2>&1 | head -1)"
+echo ""
+echo "Build tools: aapt2, aidl, zipalign (API 35)"
+echo "BusyBox:     $(busybox 2>&1 | head -1)"
+echo ""
+echo "Run 'buildchain status' to verify everything."
+echo "Run 'buildchain test' to test all tools."
+echo ""
+echo "Source the environment in your shell:"
+echo "  source /data/adb/buildchain/env.sh"
diff --git a/scripts/webui-server b/scripts/webui-server
new file mode 100755
index 0000000..0ef82ee
--- /dev/null
+++ b/scripts/webui-server
@@ -0,0 +1,157 @@
+#!/system/bin/sh
+# BuildChain WebUI — HTTP server on port 8089
+MODDIR=$(cat /data/adb/buildchain/moddir 2>/dev/null)
+WEBROOT="$MODDIR/webroot"
+CONFIG_DIR="/data/adb/buildchain"
+TOOLS="$MODDIR/tools"
+PORT=8089
+TERMUX_BIN="/data/data/com.termux/files/usr/bin"
+
+log() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [webui] $1"; }
+
+json_val() { echo "$1" | sed -n "s/.*\"$2\"[[:space:]]*:[[:space:]]*\"\([^\"]*\)\".*/\1/p"; }
+
+get_mime() {
+  case "$1" in *.html) echo "text/html";; *.css) echo "text/css";; *.js) echo "text/javascript";; *) echo "application/json";; esac
+}
+
+send_response() {
+  printf "HTTP/1.1 %s\r\nContent-Type: %s\r\nContent-Length: %d\r\nConnection: close\r\nAccess-Control-Allow-Origin: *\r\nAccess-Control-Allow-Methods: GET,POST,OPTIONS\r\nAccess-Control-Allow-Headers: Content-Type\r\n\r\n%s" \
+    "$1" "$2" "${#3}" "$3"
+}
+
+send_file() {
+  [ -f "$1" ] && send_response "200 OK" "$(get_mime "$1")" "$(cat "$1")" || send_response "404 Not Found" "text/plain" "Not Found"
+}
+
+# API: get full environment status
+api_status() {
+  cat "$CONFIG_DIR/environment.json" 2>/dev/null || echo '{"error":"not detected yet"}'
+}
+
+# API: list all tools and their paths/status
+api_tools() {
+  local result="["
+  local first=1
+
+  for tool in aapt aapt2 aidl dexdump zipalign split-select; do
+    local path="$TOOLS/build-tools/$tool"
+    local exists="false"; [ -f "$path" ] && exists="true"
+    local size=$(stat -c%s "$path" 2>/dev/null || echo 0)
+    [ "$first" = "1" ] && first=0 || result="$result,"
+    result="$result{\"name\":\"$tool\",\"category\":\"build-tools\",\"path\":\"$path\",\"exists\":$exists,\"size\":$size}"
+  done
+
+  for tool in adb fastboot sqlite3 e2fsdroid etc1tool mke2fs make_f2fs sload_f2fs hprof-conv; do
+    local path="$TOOLS/platform-tools/$tool"
+    local exists="false"; [ -f "$path" ] && exists="true"
+    local size=$(stat -c%s "$path" 2>/dev/null || echo 0)
+    result="$result,{\"name\":\"$tool\",\"category\":\"platform-tools\",\"path\":\"$path\",\"exists\":$exists,\"size\":$size}"
+  done
+
+  result="$result,{\"name\":\"busybox\",\"category\":\"system\",\"path\":\"$TOOLS/busybox\",\"exists\":$([ -f "$TOOLS/busybox" ] && echo true || echo false),\"size\":$(stat -c%s "$TOOLS/busybox" 2>/dev/null || echo 0)}"
+
+  # Termux packages
+  for tool in java javac python3 kotlin kotlinc gradle git cmake make clang gcc g++ d8 apksigner jarsigner keytool; do
+    local tpath="$TERMUX_BIN/$tool"
+    local exists="false"; [ -f "$tpath" ] && exists="true"
+    result="$result,{\"name\":\"$tool\",\"category\":\"termux\",\"path\":\"$tpath\",\"exists\":$exists,\"size\":0}"
+  done
+
+  echo "${result}]"
+}
+
+# API: get current PATH
+api_paths() {
+  local syspath=$(echo "$PATH" | tr ':' '\n')
+  local result="["
+  local first=1
+  for p in $syspath; do
+    [ "$first" = "1" ] && first=0 || result="$result,"
+    result="$result\"$p\""
+  done
+  echo "${result}]"
+}
+
+# API: run buildchain test
+api_test() {
+  local result=""
+  result=$(sh "$MODDIR/scripts/buildchain" test 2>&1)
+  result=$(echo "$result" | sed 's/\\/\\\\/g; s/"/\\"/g' | tr '\n' '|' | sed 's/|/\\n/g')
+  echo "{\"output\":\"$result\"}"
+}
+
+# API: run setup (returns instructions since it needs Termux context)
+api_setup_status() {
+  local missing=""
+  for pkg in java python3 kotlinc gradle git cmake clang; do
+    [ ! -f "$TERMUX_BIN/$pkg" ] && missing="$missing $pkg"
+  done
+  if [ -z "$missing" ]; then
+    echo '{"complete":true,"missing":[]}'
+  else
+    missing=$(echo "$missing" | sed 's/^ //' | sed 's/ /","/g')
+    echo "{\"complete\":false,\"missing\":[\"$missing\"]}"
+  fi
+}
+
+# API: get buildchain log
+api_log() {
+  local lines="${1:-50}"
+  local content=$(tail -n "$lines" "$CONFIG_DIR/buildchain.log" 2>/dev/null)
+  content=$(echo "$content" | sed 's/\\/\\\\/g; s/"/\\"/g' | tr '\n' '|' | sed 's/|/\\n/g')
+  echo "{\"log\":\"$content\"}"
+}
+
+# API: busybox applet list
+api_busybox() {
+  local applets=$("$TOOLS/busybox" --list 2>/dev/null | tr '\n' ',' | sed 's/,$//')
+  local count=$("$TOOLS/busybox" --list 2>/dev/null | wc -l)
+  local version=$("$TOOLS/busybox" 2>&1 | head -1 | sed 's/"/\\"/g')
+  echo "{\"version\":\"$version\",\"count\":$count,\"applets\":\"$applets\"}"
+}
+
+handle_request() {
+  local method path body content_length
+
+  read -r request_line
+  method=$(echo "$request_line" | awk '{print $1}')
+  path=$(echo "$request_line" | awk '{print $2}' | cut -d'?' -f1)
+
+  while read -r header; do
+    header=$(echo "$header" | tr -d '\r')
+    [ -z "$header" ] && break
+    case "$header" in Content-Length:*) content_length=$(echo "$header" | awk '{print $2}') ;; esac
+  done
+
+  body=""
+  if [ "$method" = "POST" ] && [ -n "$content_length" ] && [ "$content_length" -gt 0 ] 2>/dev/null; then
+    body=$(dd bs=1 count="$content_length" 2>/dev/null)
+  fi
+
+  [ "$method" = "OPTIONS" ] && { send_response "200 OK" "text/plain" ""; return; }
+
+  case "$method $path" in
+    "GET /")           send_file "$WEBROOT/index.html" ;;
+    "GET /css/"*|"GET /js/"*) send_file "$WEBROOT$path" ;;
+    "GET /api/status")  send_response "200 OK" "application/json" "$(api_status)" ;;
+    "GET /api/tools")   send_response "200 OK" "application/json" "$(api_tools)" ;;
+    "GET /api/paths")   send_response "200 OK" "application/json" "$(api_paths)" ;;
+    "GET /api/test")    send_response "200 OK" "application/json" "$(api_test)" ;;
+    "GET /api/setup")   send_response "200 OK" "application/json" "$(api_setup_status)" ;;
+    "GET /api/log")     send_response "200 OK" "application/json" "$(api_log)" ;;
+    "GET /api/busybox") send_response "200 OK" "application/json" "$(api_busybox)" ;;
+    "POST /api/redetect")
+      sh "$MODDIR/service.sh" &
+      send_response "200 OK" "application/json" '{"ok":true}'
+      ;;
+    *) send_response "404 Not Found" "application/json" '{"error":"not found"}' ;;
+  esac
+}
+
+log "Starting on port $PORT"
+while true; do
+  handle_request | busybox nc -ll -p "$PORT" -s 127.0.0.1 2>/dev/null \
+    || handle_request | toybox nc -L -p "$PORT" -s 127.0.0.1 2>/dev/null \
+    || { log "ERROR: No listener"; exit 1; }
+done
diff --git a/service.sh b/service.sh
new file mode 100755
index 0000000..54744d4
--- /dev/null
+++ b/service.sh
@@ -0,0 +1,195 @@
+#!/system/bin/sh
+# BuildChain — late service: link tools into framework, hook Termux, start WebUI
+MODDIR=${0%/*}
+CONFIG_DIR="/data/adb/buildchain"
+LOG="$CONFIG_DIR/buildchain.log"
+PID_FILE="$CONFIG_DIR/webui.pid"
+TOOLS="$MODDIR/tools"
+TERMUX_PREFIX="/data/data/com.termux/files/usr"
+TERMUX_BIN="$TERMUX_PREFIX/bin"
+TERMUX_LIB="$TERMUX_PREFIX/lib"
+TERMUX_ETC="$TERMUX_PREFIX/etc"
+TERMUX_HOME="/data/data/com.termux/files/home"
+
+log() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> "$LOG"; }
+
+mkdir -p "$CONFIG_DIR"
+log "BuildChain service starting"
+
+# Wait for system to settle
+sleep 8
+
+#############################
+# Detect installed components
+#############################
+
+detect_environment() {
+  local env_file="$CONFIG_DIR/environment.json"
+
+  local has_termux="false"
+  local has_termux_api="false"
+  local has_java="false"
+  local java_version=""
+  local has_python="false"
+  local python_version=""
+  local has_kotlin="false"
+  local kotlin_version=""
+  local has_gradle="false"
+  local gradle_version=""
+  local has_git="false"
+
+  [ -d "$TERMUX_BIN" ] && has_termux="true"
+
+  # Check Termux packages
+  if [ "$has_termux" = "true" ]; then
+    [ -f "$TERMUX_BIN/termux-api-start" ] || pm list packages 2>/dev/null | grep -q "com.termux.api" && has_termux_api="true"
+    if [ -f "$TERMUX_BIN/java" ]; then
+      has_java="true"
+      java_version=$("$TERMUX_BIN/java" -version 2>&1 | head -1)
+    fi
+    if [ -f "$TERMUX_BIN/python" ] || [ -f "$TERMUX_BIN/python3" ]; then
+      has_python="true"
+      python_version=$("$TERMUX_BIN/python3" --version 2>/dev/null || "$TERMUX_BIN/python" --version 2>/dev/null)
+    fi
+    if [ -f "$TERMUX_BIN/kotlin" ] || [ -f "$TERMUX_BIN/kotlinc" ]; then
+      has_kotlin="true"
+      kotlin_version=$("$TERMUX_BIN/kotlinc" -version 2>&1 | head -1)
+    fi
+    if [ -f "$TERMUX_BIN/gradle" ]; then
+      has_gradle="true"
+      gradle_version=$("$TERMUX_BIN/gradle" --version 2>/dev/null | grep "Gradle " | head -1)
+    fi
+    [ -f "$TERMUX_BIN/git" ] && has_git="true"
+  fi
+
+  # Arch
+  local arch=$(uname -m)
+  local api=$(getprop ro.build.version.sdk)
+  local device=$(getprop ro.product.model)
+
+  cat > "$env_file" << ENVJSON
+{
+  "arch": "$arch",
+  "api_level": "$api",
+  "device": "$device",
+  "termux": $has_termux,
+  "termux_api": $has_termux_api,
+  "java": $has_java,
+  "java_version": "$java_version",
+  "python": $has_python,
+  "python_version": "$python_version",
+  "kotlin": $has_kotlin,
+  "kotlin_version": "$kotlin_version",
+  "gradle": $has_gradle,
+  "gradle_version": "$gradle_version",
+  "git": $has_git,
+  "build_tools_version": "35.0.2",
+  "busybox": true
+}
+ENVJSON
+
+  log "Environment detected: termux=$has_termux java=$has_java python=$has_python kotlin=$has_kotlin gradle=$has_gradle"
+}
+
+detect_environment
+
+#############################
+# Link build tools into system PATH (via /system/xbin overlay)
+#############################
+
+link_system_tools() {
+  local xbin="$MODDIR/system/xbin"
+  mkdir -p "$xbin"
+
+  # Build tools — always available system-wide
+  for tool in aapt aapt2 aidl dexdump zipalign split-select; do
+    [ -f "$TOOLS/build-tools/$tool" ] && ln -sf "$TOOLS/build-tools/$tool" "$xbin/$tool" 2>/dev/null
+  done
+
+  # Platform tools that aren't already in /system/bin
+  for tool in sqlite3 etc1tool hprof-conv e2fsdroid make_f2fs sload_f2fs mke2fs; do
+    [ -f "$TOOLS/platform-tools/$tool" ] && ln -sf "$TOOLS/platform-tools/$tool" "$xbin/$tool" 2>/dev/null
+  done
+
+  # Our management scripts
+  for script in "$MODDIR"/scripts/*; do
+    [ -f "$script" ] && ln -sf "$script" "$xbin/$(basename $script)" 2>/dev/null
+  done
+
+  log "System tools linked to $xbin"
+}
+
+link_system_tools
+
+#############################
+# Hook into Termux
+#############################
+
+hook_termux() {
+  if [ ! -d "$TERMUX_BIN" ]; then
+    log "Termux not installed — skipping hooks"
+    return
+  fi
+
+  # Symlink build tools into Termux bin (so they're on Termux's PATH too)
+  for tool in aapt aapt2 aidl dexdump zipalign split-select; do
+    [ -f "$TOOLS/build-tools/$tool" ] && ln -sf "$TOOLS/build-tools/$tool" "$TERMUX_BIN/$tool" 2>/dev/null
+  done
+
+  # Link our CLI scripts into Termux
+  for script in "$MODDIR"/scripts/*; do
+    [ -f "$script" ] && ln -sf "$script" "$TERMUX_BIN/$(basename $script)" 2>/dev/null
+  done
+
+  # Create Termux profile.d hook for environment
+  mkdir -p "$TERMUX_ETC/profile.d"
+  cat > "$TERMUX_ETC/profile.d/buildchain.sh" << 'PROFEOF'
+# BuildChain — auto-sourced by Termux on shell start
+[ -f /data/adb/buildchain/env.sh ] && . /data/adb/buildchain/env.sh
+PROFEOF
+
+  # Write the environment file
+  cat > "$CONFIG_DIR/env.sh" << ENVEOF
+# BuildChain environment
+export BUILDCHAIN_HOME="$MODDIR"
+export ANDROID_BUILD_TOOLS="$TOOLS/build-tools"
+export ANDROID_PLATFORM_TOOLS="$TOOLS/platform-tools"
+export ANDROID_HOME="$TERMUX_HOME/android-sdk"
+export ANDROID_SDK_ROOT="\$ANDROID_HOME"
+export PATH="\$ANDROID_BUILD_TOOLS:\$ANDROID_PLATFORM_TOOLS:\$PATH"
+
+# Java — detect from Termux
+for jdir in $TERMUX_PREFIX/lib/jvm/java-21-openjdk $TERMUX_PREFIX/lib/jvm/java-17-openjdk; do
+  if [ -d "\$jdir" ]; then
+    export JAVA_HOME="\$jdir"
+    export PATH="\$JAVA_HOME/bin:\$PATH"
+    break
+  fi
+done
+
+# Gradle home
+[ -d "$TERMUX_HOME/.gradle" ] && export GRADLE_USER_HOME="$TERMUX_HOME/.gradle"
+
+# Kotlin
+[ -d "$TERMUX_PREFIX/share/kotlin" ] && export KOTLIN_HOME="$TERMUX_PREFIX/share/kotlin"
+ENVEOF
+
+  log "Termux hooks installed"
+}
+
+hook_termux
+
+#############################
+# Start WebUI
+#############################
+
+if [ -f "$PID_FILE" ]; then
+  kill $(cat "$PID_FILE") 2>/dev/null
+  rm -f "$PID_FILE"
+fi
+
+log "Starting WebUI on port 8089"
+nohup sh "$MODDIR/scripts/webui-server" >> "$LOG" 2>&1 &
+echo $! > "$PID_FILE"
+
+log "BuildChain service complete (WebUI PID: $(cat $PID_FILE))"
diff --git a/tools/build-tools/aapt b/tools/build-tools/aapt
new file mode 100755
index 0000000..724a9e7
Binary files /dev/null and b/tools/build-tools/aapt differ
diff --git a/tools/build-tools/aapt2 b/tools/build-tools/aapt2
new file mode 100755
index 0000000..09fa323
Binary files /dev/null and b/tools/build-tools/aapt2 differ
diff --git a/tools/build-tools/aidl b/tools/build-tools/aidl
new file mode 100755
index 0000000..11c7155
Binary files /dev/null and b/tools/build-tools/aidl differ
diff --git a/tools/build-tools/dexdump b/tools/build-tools/dexdump
new file mode 100755
index 0000000..a7dee76
Binary files /dev/null and b/tools/build-tools/dexdump differ
diff --git a/tools/build-tools/split-select b/tools/build-tools/split-select
new file mode 100755
index 0000000..b3f7593
Binary files /dev/null and b/tools/build-tools/split-select differ
diff --git a/tools/build-tools/zipalign b/tools/build-tools/zipalign
new file mode 100755
index 0000000..ff47e8e
Binary files /dev/null and b/tools/build-tools/zipalign differ
diff --git a/tools/busybox b/tools/busybox
new file mode 100755
index 0000000..7081454
Binary files /dev/null and b/tools/busybox differ
diff --git a/tools/platform-tools/adb b/tools/platform-tools/adb
new file mode 100755
index 0000000..59209b0
Binary files /dev/null and b/tools/platform-tools/adb differ
diff --git a/tools/platform-tools/e2fsdroid b/tools/platform-tools/e2fsdroid
new file mode 100755
index 0000000..8285f63
Binary files /dev/null and b/tools/platform-tools/e2fsdroid differ
diff --git a/tools/platform-tools/etc1tool b/tools/platform-tools/etc1tool
new file mode 100755
index 0000000..6faca52
Binary files /dev/null and b/tools/platform-tools/etc1tool differ
diff --git a/tools/platform-tools/fastboot b/tools/platform-tools/fastboot
new file mode 100755
index 0000000..7d38da7
Binary files /dev/null and b/tools/platform-tools/fastboot differ
diff --git a/tools/platform-tools/hprof-conv b/tools/platform-tools/hprof-conv
new file mode 100755
index 0000000..b9c155b
Binary files /dev/null and b/tools/platform-tools/hprof-conv differ
diff --git a/tools/platform-tools/make_f2fs b/tools/platform-tools/make_f2fs
new file mode 100755
index 0000000..9bdbb13
Binary files /dev/null and b/tools/platform-tools/make_f2fs differ
diff --git a/tools/platform-tools/make_f2fs_casefold b/tools/platform-tools/make_f2fs_casefold
new file mode 100755
index 0000000..b8847ed
Binary files /dev/null and b/tools/platform-tools/make_f2fs_casefold differ
diff --git a/tools/platform-tools/mke2fs b/tools/platform-tools/mke2fs
new file mode 100755
index 0000000..40ef30a
Binary files /dev/null and b/tools/platform-tools/mke2fs differ
diff --git a/tools/platform-tools/sload_f2fs b/tools/platform-tools/sload_f2fs
new file mode 100755
index 0000000..7f21381
Binary files /dev/null and b/tools/platform-tools/sload_f2fs differ
diff --git a/tools/platform-tools/sqlite3 b/tools/platform-tools/sqlite3
new file mode 100755
index 0000000..0738b39
Binary files /dev/null and b/tools/platform-tools/sqlite3 differ
diff --git a/uninstall.sh b/uninstall.sh
new file mode 100755
index 0000000..0a171f2
--- /dev/null
+++ b/uninstall.sh
@@ -0,0 +1,15 @@
+#!/system/bin/sh
+CONFIG_DIR="/data/adb/buildchain"
+PID_FILE="$CONFIG_DIR/webui.pid"
+TERMUX_BIN="/data/data/com.termux/files/usr/bin"
+TERMUX_ETC="/data/data/com.termux/files/usr/etc"
+
+[ -f "$PID_FILE" ] && kill $(cat "$PID_FILE") 2>/dev/null
+
+# Remove Termux symlinks
+for tool in aapt aapt2 aidl dexdump zipalign split-select buildchain buildchain-setup bc-build bc-sign; do
+  rm -f "$TERMUX_BIN/$tool" 2>/dev/null
+done
+rm -f "$TERMUX_ETC/profile.d/buildchain.sh" 2>/dev/null
+
+rm -rf "$CONFIG_DIR"
diff --git a/webroot/css/style.css b/webroot/css/style.css
new file mode 100644
index 0000000..3b91dd9
--- /dev/null
+++ b/webroot/css/style.css
@@ -0,0 +1,51 @@
+:root {
+  --bg: #0a0e17; --card: #111827; --card-hover: #1a2332; --input: #1e293b;
+  --border: #1e3a5f; --text: #e2e8f0; --text2: #94a3b8; --muted: #64748b;
+  --accent: #10b981; --accent-glow: rgba(16,185,129,0.3);
+  --success: #22c55e; --warn: #f59e0b; --danger: #ef4444;
+  --radius: 12px; --sm: 8px;
+}
+* { margin:0; padding:0; box-sizing:border-box; }
+body { font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',system-ui,sans-serif; background:var(--bg); color:var(--text); min-height:100vh; }
+body::before { content:''; position:fixed; inset:0; background:radial-gradient(ellipse at 30% 50%,rgba(16,185,129,0.06) 0%,transparent 50%),radial-gradient(ellipse at 70% 20%,rgba(59,130,246,0.05) 0%,transparent 50%); pointer-events:none; z-index:0; }
+.app { position:relative; z-index:1; max-width:540px; margin:0 auto; padding:16px; padding-bottom:80px; }
+.header { text-align:center; padding:20px 0 16px; }
+.header h1 { font-size:22px; font-weight:700; color:var(--accent); }
+.header p { font-size:13px; color:var(--muted); margin-top:4px; }
+.section { margin-bottom:16px; }
+.section-title { font-size:11px; font-weight:600; text-transform:uppercase; letter-spacing:1.2px; color:var(--muted); padding:0 4px; margin-bottom:8px; }
+.card { background:var(--card); border:1px solid var(--border); border-radius:var(--radius); overflow:hidden; margin-bottom:8px; }
+.card-row { display:flex; align-items:center; justify-content:space-between; padding:12px 16px; }
+.card-row+.card-row { border-top:1px solid var(--border); }
+.card-row-info { flex:1; min-width:0; }
+.card-row-label { font-size:14px; font-weight:500; }
+.card-row-desc { font-size:12px; color:var(--muted); margin-top:2px; word-break:break-all; }
+.prop-name { font-family:'SF Mono','Fira Code',monospace; font-size:12px; color:var(--accent); }
+.badge { display:inline-block; padding:2px 8px; border-radius:10px; font-size:11px; font-weight:600; }
+.badge-ok { background:rgba(34,197,94,0.15); color:var(--success); }
+.badge-miss { background:rgba(239,68,68,0.15); color:var(--danger); }
+.badge-info { background:rgba(59,130,246,0.15); color:#3b82f6; }
+.tool-grid { display:grid; grid-template-columns:1fr 1fr; gap:6px; padding:12px 16px; }
+.tool-chip { padding:8px 10px; border-radius:var(--sm); border:1px solid var(--border); background:var(--input); font-size:12px; display:flex; align-items:center; gap:6px; }
+.tool-chip .dot { width:6px; height:6px; border-radius:50%; flex-shrink:0; }
+.tool-chip .dot.ok { background:var(--success); box-shadow:0 0 6px var(--success); }
+.tool-chip .dot.miss { background:var(--muted); }
+.btn { padding:10px 16px; border-radius:var(--sm); border:1px solid var(--border); background:var(--card); color:var(--text); font-size:13px; font-weight:500; cursor:pointer; text-align:center; }
+.btn:hover { border-color:var(--accent); }
+.btn-primary { background:var(--accent); border-color:var(--accent); color:#000; font-weight:600; }
+.btn-primary:hover { box-shadow:0 4px 16px var(--accent-glow); }
+.actions { display:grid; grid-template-columns:1fr 1fr; gap:8px; margin-top:12px; }
+pre.output { background:#030712; border:1px solid var(--border); border-radius:var(--sm); padding:12px; font-family:'SF Mono','Fira Code',monospace; font-size:11px; line-height:1.5; color:var(--text2); white-space:pre-wrap; word-break:break-all; max-height:400px; overflow-y:auto; }
+.toast { position:fixed; bottom:20px; left:50%; transform:translateX(-50%) translateY(80px); padding:12px 20px; border-radius:var(--sm); background:var(--card); border:1px solid var(--border); color:var(--text); font-size:13px; box-shadow:0 8px 32px rgba(0,0,0,0.4); opacity:0; transition:all 0.3s; z-index:100; }
+.toast.show { transform:translateX(-50%) translateY(0); opacity:1; }
+.toast.success { border-color:var(--success); }
+.toast.error { border-color:var(--danger); }
+.tab-bar { position:fixed; bottom:0; left:0; right:0; background:rgba(10,14,23,0.95); backdrop-filter:blur(20px); border-top:1px solid var(--border); display:flex; justify-content:center; gap:4px; padding:8px 16px; padding-bottom:max(8px,env(safe-area-inset-bottom)); z-index:50; }
+.tab-item { flex:1; max-width:90px; display:flex; flex-direction:column; align-items:center; gap:3px; padding:6px 4px; border-radius:var(--sm); color:var(--muted); font-size:10px; font-weight:500; cursor:pointer; border:none; background:none; }
+.tab-item.active { color:var(--accent); }
+.tab-item svg { width:20px; height:20px; fill:currentColor; }
+.page { display:none; } .page.active { display:block; }
+.info-grid { display:grid; grid-template-columns:1fr 1fr; gap:1px; background:var(--border); border:1px solid var(--border); border-radius:var(--radius); }
+.info-cell { background:var(--card); padding:10px 14px; }
+.info-label { font-size:11px; color:var(--muted); text-transform:uppercase; letter-spacing:0.5px; }
+.info-value { font-size:13px; font-weight:600; margin-top:3px; }
diff --git a/webroot/index.html b/webroot/index.html
new file mode 100644
index 0000000..28041ac
--- /dev/null
+++ b/webroot/index.html
@@ -0,0 +1,136 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+  <meta name="theme-color" content="#0a0e17">
+  <title>BuildChain</title>
+  <link rel="stylesheet" href="/css/style.css">
+</head>
+<body>
+<div class="app">
+  <div class="header">
+    <h1>BuildChain</h1>
+    <p id="device-info">Detecting...</p>
+  </div>
+
+  <!-- DASHBOARD -->
+  <div class="page active" id="page-dash">
+    <div class="section">
+      <div class="section-title">Environment</div>
+      <div class="info-grid">
+        <div class="info-cell"><div class="info-label">Device</div><div class="info-value" id="env-device">-</div></div>
+        <div class="info-cell"><div class="info-label">Android / API</div><div class="info-value" id="env-api">-</div></div>
+        <div class="info-cell"><div class="info-label">Architecture</div><div class="info-value" id="env-arch">-</div></div>
+        <div class="info-cell"><div class="info-label">Build Tools</div><div class="info-value" id="env-bt">35.0.2</div></div>
+      </div>
+    </div>
+
+    <div class="section">
+      <div class="section-title">Toolchain Status</div>
+      <div class="card">
+        <div id="status-grid" class="tool-grid"></div>
+      </div>
+    </div>
+
+    <div class="section">
+      <div class="section-title">Setup</div>
+      <div class="card">
+        <div class="card-row">
+          <div class="card-row-info">
+            <div class="card-row-label">Termux Packages</div>
+            <div class="card-row-desc" id="setup-status">Checking...</div>
+          </div>
+          <span class="badge" id="setup-badge">...</span>
+        </div>
+        <div class="card-row">
+          <div class="card-row-info">
+            <div class="card-row-desc">Run in Termux: <span class="prop-name">buildchain setup</span></div>
+          </div>
+        </div>
+      </div>
+    </div>
+
+    <div class="actions">
+      <button class="btn btn-primary" onclick="loadDash()">Refresh</button>
+      <button class="btn" onclick="redetect()">Re-detect</button>
+    </div>
+  </div>
+
+  <!-- TOOLS -->
+  <div class="page" id="page-tools">
+    <div class="section">
+      <div class="section-title">Build Tools (API 35 — Static ARM64)</div>
+      <div class="card" id="build-tools-list"></div>
+    </div>
+    <div class="section">
+      <div class="section-title">Platform Tools</div>
+      <div class="card" id="platform-tools-list"></div>
+    </div>
+    <div class="section">
+      <div class="section-title">Termux Packages</div>
+      <div class="card" id="termux-tools-list"></div>
+    </div>
+    <div class="section">
+      <div class="section-title">BusyBox</div>
+      <div class="card" id="busybox-info"></div>
+    </div>
+  </div>
+
+  <!-- TEST -->
+  <div class="page" id="page-test">
+    <div class="section">
+      <div class="section-title">Tool Test Results</div>
+      <div class="card" style="padding:12px 16px">
+        <button class="btn btn-primary" onclick="runTest()" style="width:100%;margin-bottom:8px">Run All Tests</button>
+        <pre class="output" id="test-output">Tap "Run All Tests" to verify the toolchain.</pre>
+      </div>
+    </div>
+    <div class="section">
+      <div class="section-title">Service Log</div>
+      <div class="card" style="padding:12px 16px">
+        <button class="btn" onclick="loadLog()" style="width:100%;margin-bottom:8px">Load Log</button>
+        <pre class="output" id="log-output">Tap to load.</pre>
+      </div>
+    </div>
+  </div>
+
+  <!-- PATHS -->
+  <div class="page" id="page-paths">
+    <div class="section">
+      <div class="section-title">System PATH</div>
+      <div class="card" id="path-list"></div>
+    </div>
+    <div class="section">
+      <div class="section-title">Environment Variables</div>
+      <div class="card" style="padding:12px 16px">
+        <pre class="output" id="env-output">Loading...</pre>
+      </div>
+    </div>
+  </div>
+</div>
+
+<div class="toast" id="toast"></div>
+
+<div class="tab-bar">
+  <button class="tab-item active" data-tab="dash">
+    <svg viewBox="0 0 24 24"><path d="M3 13h8V3H3v10zm0 8h8v-6H3v6zm10 0h8V11h-8v10zm0-18v6h8V3h-8z"/></svg>
+    Status
+  </button>
+  <button class="tab-item" data-tab="tools">
+    <svg viewBox="0 0 24 24"><path d="M22.7 19l-9.1-9.1c.9-2.3.4-5-1.5-6.9-2-2-5-2.4-7.4-1.3L9 6 6 9 1.6 4.7C.4 7.1.9 10.1 2.9 12.1c1.9 1.9 4.6 2.4 6.9 1.5l9.1 9.1c.4.4 1 .4 1.4 0l2.3-2.3c.5-.4.5-1.1.1-1.4z"/></svg>
+    Tools
+  </button>
+  <button class="tab-item" data-tab="test">
+    <svg viewBox="0 0 24 24"><path d="M20 8h-2.81c-.45-.78-1.07-1.45-1.82-1.96L17 4.41 15.59 3l-2.17 2.17C12.96 5.06 12.49 5 12 5s-.96.06-1.41.17L8.41 3 7 4.41l1.62 1.63C7.88 6.55 7.26 7.22 6.81 8H4v2h2.09c-.05.33-.09.66-.09 1v1H4v2h2v1c0 .34.04.67.09 1H4v2h2.81c1.04 1.79 2.97 3 5.19 3s4.15-1.21 5.19-3H20v-2h-2.09c.05-.33.09-.66.09-1v-1h2v-2h-2v-1c0-.34-.04-.67-.09-1H20V8zm-6 8h-4v-2h4v2zm0-4h-4v-2h4v2z"/></svg>
+    Test
+  </button>
+  <button class="tab-item" data-tab="paths">
+    <svg viewBox="0 0 24 24"><path d="M20 6h-8l-2-2H4c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h16c1.1 0 2-.9 2-2V8c0-1.1-.9-2-2-2zm0 12H4V8h16v10z"/></svg>
+    Paths
+  </button>
+</div>
+
+<script src="/js/app.js"></script>
+</body>
+</html>
diff --git a/webroot/js/app.js b/webroot/js/app.js
new file mode 100644
index 0000000..c5dea0b
--- /dev/null
+++ b/webroot/js/app.js
@@ -0,0 +1,194 @@
+// BuildChain WebUI
+
+let currentTab = 'dash';
+let toastTimer = null;
+
+async function api(path) {
+  try { return await (await fetch(path)).json(); } catch(e) { showToast('Connection error','error'); return null; }
+}
+async function post(path, body) {
+  try { return await (await fetch(path, {method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify(body)})).json(); } catch(e) { return null; }
+}
+
+function showToast(msg, type='success') {
+  const el = document.getElementById('toast');
+  el.textContent = msg; el.className = 'toast ' + type + ' show';
+  clearTimeout(toastTimer); toastTimer = setTimeout(() => el.className = 'toast', 2500);
+}
+
+function switchTab(tab) {
+  currentTab = tab;
+  document.querySelectorAll('.page').forEach(p => p.classList.remove('active'));
+  document.querySelectorAll('.tab-item').forEach(t => t.classList.remove('active'));
+  document.getElementById('page-' + tab).classList.add('active');
+  document.querySelector(`[data-tab="${tab}"]`).classList.add('active');
+  switch(tab) {
+    case 'dash': loadDash(); break;
+    case 'tools': loadTools(); break;
+    case 'test': break;
+    case 'paths': loadPaths(); break;
+  }
+}
+
+function esc(s) { return (s||'').replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;'); }
+
+// ---- Dashboard ----
+async function loadDash() {
+  const env = await api('/api/status');
+  if (env) {
+    document.getElementById('device-info').textContent = `${env.device || '?'} — Android ${env.api_level || '?'} — ${env.arch || '?'}`;
+    document.getElementById('env-device').textContent = env.device || '-';
+    document.getElementById('env-api').textContent = `API ${env.api_level || '?'}`;
+    document.getElementById('env-arch').textContent = env.arch || '-';
+  }
+
+  // Tool status grid
+  const tools = await api('/api/tools');
+  const grid = document.getElementById('status-grid');
+  if (tools) {
+    grid.innerHTML = tools.map(t => `
+      <div class="tool-chip">
+        <span class="dot ${t.exists ? 'ok' : 'miss'}"></span>
+        ${t.name}
+      </div>
+    `).join('');
+  }
+
+  // Setup status
+  const setup = await api('/api/setup');
+  const statusEl = document.getElementById('setup-status');
+  const badgeEl = document.getElementById('setup-badge');
+  if (setup) {
+    if (setup.complete) {
+      statusEl.textContent = 'All packages installed';
+      badgeEl.textContent = 'Ready';
+      badgeEl.className = 'badge badge-ok';
+    } else {
+      statusEl.textContent = 'Missing: ' + setup.missing.join(', ');
+      badgeEl.textContent = 'Incomplete';
+      badgeEl.className = 'badge badge-miss';
+    }
+  }
+}
+
+async function redetect() {
+  showToast('Re-detecting environment...');
+  await post('/api/redetect', {});
+  setTimeout(loadDash, 3000);
+}
+
+// ---- Tools ----
+async function loadTools() {
+  const tools = await api('/api/tools');
+  if (!tools) return;
+
+  const buildTools = tools.filter(t => t.category === 'build-tools');
+  const platTools = tools.filter(t => t.category === 'platform-tools');
+  const termuxTools = tools.filter(t => t.category === 'termux');
+
+  document.getElementById('build-tools-list').innerHTML = buildTools.map(t => `
+    <div class="card-row">
+      <div class="card-row-info">
+        <div class="card-row-label">${t.name}</div>
+        <div class="card-row-desc">${t.path}</div>
+      </div>
+      <span class="badge ${t.exists ? 'badge-ok' : 'badge-miss'}">${t.exists ? (t.size/1024).toFixed(0)+'K' : 'missing'}</span>
+    </div>
+  `).join('');
+
+  document.getElementById('platform-tools-list').innerHTML = platTools.map(t => `
+    <div class="card-row">
+      <div class="card-row-info">
+        <div class="card-row-label">${t.name}</div>
+        <div class="card-row-desc">${t.path}</div>
+      </div>
+      <span class="badge ${t.exists ? 'badge-ok' : 'badge-miss'}">${t.exists ? (t.size/1024).toFixed(0)+'K' : 'missing'}</span>
+    </div>
+  `).join('');
+
+  document.getElementById('termux-tools-list').innerHTML = termuxTools.map(t => `
+    <div class="card-row">
+      <div class="card-row-info">
+        <div class="card-row-label">${t.name}</div>
+        <div class="card-row-desc">${t.category}</div>
+      </div>
+      <span class="badge ${t.exists ? 'badge-ok' : 'badge-miss'}">${t.exists ? 'installed' : 'not found'}</span>
+    </div>
+  `).join('');
+
+  // BusyBox
+  const bb = await api('/api/busybox');
+  const bbc = document.getElementById('busybox-info');
+  if (bb) {
+    bbc.innerHTML = `
+      <div class="card-row">
+        <div class="card-row-info">
+          <div class="card-row-label">${esc(bb.version)}</div>
+          <div class="card-row-desc">${bb.count} applets</div>
+        </div>
+        <span class="badge badge-ok">active</span>
+      </div>
+      <div class="card-row">
+        <div class="card-row-info">
+          <div class="card-row-desc" style="font-family:monospace;font-size:10px;line-height:1.4;max-height:120px;overflow-y:auto">${esc(bb.applets).replace(/,/g, ', ')}</div>
+        </div>
+      </div>
+    `;
+  }
+}
+
+// ---- Test ----
+async function runTest() {
+  const out = document.getElementById('test-output');
+  out.textContent = 'Running tests...';
+  const res = await api('/api/test');
+  if (res && res.output) {
+    out.textContent = res.output;
+  } else {
+    out.textContent = 'Failed to run tests';
+  }
+}
+
+async function loadLog() {
+  const out = document.getElementById('log-output');
+  out.textContent = 'Loading...';
+  const res = await api('/api/log');
+  if (res && res.log) {
+    out.textContent = res.log;
+  } else {
+    out.textContent = 'No log available';
+  }
+}
+
+// ---- Paths ----
+async function loadPaths() {
+  const paths = await api('/api/paths');
+  const pc = document.getElementById('path-list');
+  if (paths) {
+    pc.innerHTML = paths.map((p, i) => `
+      <div class="card-row">
+        <div class="card-row-info">
+          <span class="prop-name">${esc(p)}</span>
+        </div>
+        <span class="badge badge-info">#${i}</span>
+      </div>
+    `).join('');
+  }
+
+  // Env file
+  const envOut = document.getElementById('env-output');
+  try {
+    const res = await fetch('/api/status');
+    const env = await res.json();
+    envOut.textContent = JSON.stringify(env, null, 2);
+  } catch(e) {
+    envOut.textContent = 'Failed to load';
+  }
+}
+
+// ---- Init ----
+document.addEventListener('DOMContentLoaded', () => {
+  document.querySelectorAll('.tab-item').forEach(t =>
+    t.addEventListener('click', () => switchTab(t.dataset.tab)));
+  switchTab('dash');
+});