diff --git a/.secrets.baseline b/.secrets.baseline
index 874acf9..d1e81f4 100644
--- a/.secrets.baseline
+++ b/.secrets.baseline
@@ -133,9 +133,9 @@
         "filename": "scripts/init_system.sh",
         "hashed_secret": "96183ea4ff07d786ed3233777364ddbf14eb74cc",
         "is_verified": false,
-        "line_number": 19
+        "line_number": 23
       }
     ]
   },
-  "generated_at": "2026-02-24T14:14:56Z"
+  "generated_at": "2026-03-13T14:03:33Z"
 }
diff --git a/scripts/init_system.sh b/scripts/init_system.sh
index f35bbed..fc45f18 100755
--- a/scripts/init_system.sh
+++ b/scripts/init_system.sh
@@ -3,6 +3,10 @@
 # Initialize host prerequisites for OpenCode + A2A (idempotent).
 set -euo pipefail
 
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./init_system_uv_release_manifest.sh
+source "${SCRIPT_DIR}/init_system_uv_release_manifest.sh"
+
 OPENCODE_CORE_DIR="/opt/.opencode"
 SHARED_WRAPPER_DIR="/opt/opencode-a2a"
 OPENCODE_A2A_DIR="${SHARED_WRAPPER_DIR}/opencode-a2a-server"
@@ -165,10 +169,10 @@ install_packages() {
   log_done "Package installation completed."
 }
 
-download_script() {
+download_file() {
   local url="$1"
   local dest="$2"
-  if ! curl -fL "$url" -o "$dest"; then
+  if ! curl -fsSL "$url" -o "$dest"; then
     return 1
   fi
   if [[ ! -s "$dest" ]]; then
@@ -177,15 +181,6 @@ download_script() {
   return 0
 }
 
-validate_script_contains() {
-  local path="$1"
-  local pattern="$2"
-  if ! grep -Eqi "$pattern" "$path"; then
-    return 1
-  fi
-  return 0
-}
-
 verify_file_checksum() {
   local path="$1"
   local expected="$2"
@@ -208,6 +203,151 @@ verify_file_checksum() {
   return 0
 }
 
+detect_linux_libc() {
+  local output=""
+  if command -v ldd >/dev/null 2>&1; then
+    output="$(ldd --version 2>&1 || true)"
+  fi
+  if printf '%s' "$output" | grep -qi "musl"; then
+    printf 'musl\n'
+    return 0
+  fi
+  if getconf GNU_LIBC_VERSION >/dev/null 2>&1; then
+    printf 'gnu\n'
+    return 0
+  fi
+  if printf '%s' "$output" | grep -Eqi "glibc|gnu libc"; then
+    printf 'gnu\n'
+    return 0
+  fi
+  return 1
+}
+
+resolve_uv_release_artifact() {
+  local arch="$1"
+  local libc="$2"
+
+  case "${arch}:${libc}" in
+    x86_64:gnu)
+      printf '%s|%s\n' "$UV_TARBALL_X86_64_GNU" "$UV_TARBALL_X86_64_GNU_SHA256"
+      ;;
+    x86_64:musl)
+      printf '%s|%s\n' "$UV_TARBALL_X86_64_MUSL" "$UV_TARBALL_X86_64_MUSL_SHA256"
+      ;;
+    aarch64:gnu)
+      printf '%s|%s\n' "$UV_TARBALL_AARCH64_GNU" "$UV_TARBALL_AARCH64_GNU_SHA256"
+      ;;
+    aarch64:musl)
+      printf '%s|%s\n' "$UV_TARBALL_AARCH64_MUSL" "$UV_TARBALL_AARCH64_MUSL_SHA256"
+      ;;
+    *)
+      return 1
+      ;;
+  esac
+}
+
+node_manual_install_hint() {
+  warn "Install Node.js >= ${NODE_MAJOR} manually from a trusted distro repository or internal mirror, then rerun init_system.sh with INSTALL_NODE=false."
+}
+
+ensure_node_from_package_manager() {
+  case "$PKG_MANAGER" in
+    apt)
+      $SUDO apt-get update
+      if ! $SUDO apt-get install -y nodejs npm; then
+        return 1
+      fi
+      ;;
+    dnf)
+      if ! $SUDO dnf install -y nodejs npm && ! $SUDO dnf install -y nodejs; then
+        return 1
+      fi
+      ;;
+    yum)
+      if ! $SUDO yum install -y nodejs npm && ! $SUDO yum install -y nodejs; then
+        return 1
+      fi
+      ;;
+    pacman)
+      if ! $SUDO pacman -Syu --noconfirm nodejs npm; then
+        return 1
+      fi
+      ;;
+    *)
+      return 1
+      ;;
+  esac
+}
+
+install_uv_from_release() {
+  local os_name
+  local arch
+  local libc
+  local resolved
+  local asset
+  local checksum
+  local tmpdir
+  local archive
+  local extract_dir
+
+  os_name="$(uname -s)"
+  if [[ "$os_name" != "Linux" ]]; then
+    warn "Unsupported OS for pinned uv bootstrap: $os_name"
+    return 1
+  fi
+
+  arch="$(uname -m)"
+  case "$arch" in
+    x86_64|amd64) arch="x86_64" ;;
+    aarch64|arm64) arch="aarch64" ;;
+    *)
+      warn "Unsupported architecture for pinned uv bootstrap: $arch"
+      return 1
+      ;;
+  esac
+
+  if ! libc="$(detect_linux_libc)"; then
+    warn "Unable to detect Linux libc for uv bootstrap."
+    return 1
+  fi
+
+  if ! resolved="$(resolve_uv_release_artifact "$arch" "$libc")"; then
+    warn "No pinned uv release artifact configured for ${arch}/${libc}."
+    return 1
+  fi
+
+  IFS='|' read -r asset checksum <<< "$resolved"
+  tmpdir="$(mktemp -d)"
+  archive="${tmpdir}/${asset}"
+  extract_dir="${tmpdir}/${asset%.tar.gz}"
+
+  if ! download_file "${UV_RELEASE_BASE_URL}/${asset}" "$archive"; then
+    rm -rf "$tmpdir"
+    return 1
+  fi
+  if ! verify_file_checksum "$archive" "$checksum"; then
+    rm -rf "$tmpdir"
+    return 1
+  fi
+  if ! tar -xzf "$archive" -C "$tmpdir"; then
+    rm -rf "$tmpdir"
+    return 1
+  fi
+  if [[ ! -x "${extract_dir}/uv" ]]; then
+    warn "Pinned uv archive is missing the uv binary: ${extract_dir}/uv"
+    rm -rf "$tmpdir"
+    return 1
+  fi
+
+  $SUDO install -d -m 755 /usr/local/bin
+  $SUDO install -m 755 "${extract_dir}/uv" /usr/local/bin/uv
+  if [[ -x "${extract_dir}/uvx" ]]; then
+    $SUDO install -m 755 "${extract_dir}/uvx" /usr/local/bin/uvx
+  fi
+  rm -rf "$tmpdir"
+  return 0
+}
+
 ensure_group() {
   local group="$1"
   if [[ -z "$group" ]]; then
@@ -335,81 +475,28 @@ if is_truthy "$INSTALL_NODE"; then
   if [[ -n "$node_major" && "$node_major" -ge "$NODE_MAJOR" ]]; then
     log_done "Node.js already installed: ${node_version}"
   else
-    log_start "Installing Node.js ${NODE_MAJOR}.x..."
-    case "$PKG_MANAGER" in
-      apt)
-        nodesource_script="$(mktemp)"
-        log_start "Downloading NodeSource setup script..."
-        if ! download_script "https://deb.nodesource.com/setup_${NODE_MAJOR}.x" "$nodesource_script"; then
-          warn "Failed to download NodeSource setup script."
-          INCOMPLETE=1
-        else
-          log_done "NodeSource setup script downloaded."
-          log_start "Validating NodeSource setup script..."
-          if ! validate_script_contains "$nodesource_script" "nodesource|NodeSource"; then
-            warn "NodeSource setup script validation failed."
-            INCOMPLETE=1
-          else
-            log_done "NodeSource setup script validated."
-            $SUDO -E bash "$nodesource_script"
-          fi
-        fi
-        rm -f "$nodesource_script"
-        $SUDO apt-get install -y nodejs
-        ;;
-      dnf)
-        nodesource_script="$(mktemp)"
-        log_start "Downloading NodeSource setup script..."
-        if ! download_script "https://rpm.nodesource.com/setup_${NODE_MAJOR}.x" "$nodesource_script"; then
-          warn "Failed to download NodeSource setup script."
-          INCOMPLETE=1
-        else
-          log_done "NodeSource setup script downloaded."
-          log_start "Validating NodeSource setup script..."
-          if ! validate_script_contains "$nodesource_script" "nodesource|NodeSource"; then
-            warn "NodeSource setup script validation failed."
-            INCOMPLETE=1
-          else
-            log_done "NodeSource setup script validated."
-            $SUDO -E bash "$nodesource_script"
-          fi
-        fi
-        rm -f "$nodesource_script"
-        $SUDO dnf install -y nodejs
-        ;;
-      yum)
-        nodesource_script="$(mktemp)"
-        log_start "Downloading NodeSource setup script..."
-        if ! download_script "https://rpm.nodesource.com/setup_${NODE_MAJOR}.x" "$nodesource_script"; then
-          warn "Failed to download NodeSource setup script."
-          INCOMPLETE=1
-        else
-          log_done "NodeSource setup script downloaded."
-          log_start "Validating NodeSource setup script..."
-          if ! validate_script_contains "$nodesource_script" "nodesource|NodeSource"; then
-            warn "NodeSource setup script validation failed."
-            INCOMPLETE=1
-          else
-            log_done "NodeSource setup script validated."
-            $SUDO -E bash "$nodesource_script"
-          fi
-        fi
-        rm -f "$nodesource_script"
-        $SUDO yum install -y nodejs
-        ;;
-      pacman)
-        $SUDO pacman -Syu --noconfirm nodejs npm
-        ;;
-      *)
-        warn "Unsupported package manager for Node.js install: $PKG_MANAGER"
-        INCOMPLETE=1
-        ;;
-    esac
+    log_start "Installing Node.js from trusted package manager repositories..."
+    if ! ensure_node_from_package_manager; then
+      warn "Node.js install via package manager failed."
+      node_manual_install_hint
+      INCOMPLETE=1
+    fi
     if command -v node >/dev/null 2>&1; then
       node_version="$(node -v 2>/dev/null || true)"
-      log_done "Node.js installed: ${node_version}"
+      node_major=""
+      if [[ "$node_version" =~ ^v([0-9]+) ]]; then
+        node_major="${BASH_REMATCH[1]}"
+      fi
+      if [[ -n "$node_major" && "$node_major" -ge "$NODE_MAJOR" ]]; then
+        log_done "Node.js installed: ${node_version}"
+      else
+        warn "Installed Node.js version does not satisfy NODE_MAJOR=${NODE_MAJOR}: ${node_version:-unknown}"
+        node_manual_install_hint
+        INCOMPLETE=1
+      fi
     else
       warn "Node.js installation failed."
+      node_manual_install_hint
       INCOMPLETE=1
     fi
   fi
@@ -465,23 +552,12 @@ if is_truthy "$INSTALL_UV"; then
       INCOMPLETE=1
     else
       log_start "Installing uv..."
-      uv_script="$(mktemp)"
-      log_start "Downloading uv install script..."
-      if ! download_script "https://astral.sh/uv/install.sh" "$uv_script"; then
-        warn "Failed to download uv install script."
+      log_start "Downloading pinned uv release tarball..."
+      if ! install_uv_from_release; then
+        warn "Pinned uv release installation failed."
+        warn "Install uv ${UV_VERSION} manually from a trusted release artifact, then rerun init_system.sh with INSTALL_UV=false."
         INCOMPLETE=1
-      else
-        log_done "uv install script downloaded."
-        log_start "Validating uv install script..."
-        if ! validate_script_contains "$uv_script" "astral|uv"; then
-          warn "uv install script validation failed."
-          INCOMPLETE=1
-        else
-          log_done "uv install script validated."
-          UV_PYTHON_INSTALL_DIR="$UV_PYTHON_INSTALL_DIR" sh "$uv_script"
-        fi
       fi
-      rm -f "$uv_script"
       if ! command -v uv >/dev/null 2>&1; then
         if [[ -x "$HOME/.local/bin/uv" ]]; then
           log_start "Moving uv into /usr/local/bin."
@@ -618,7 +694,7 @@ else
   if [[ -n "$OPENCODE_INSTALL_CMD" ]]; then
     opencode_install_script="$(mktemp)"
     log_start "Downloading OpenCode installer..."
-    if ! download_script "$OPENCODE_INSTALLER_URL" "$opencode_install_script"; then
+    if ! download_file "$OPENCODE_INSTALLER_URL" "$opencode_install_script"; then
       warn "Failed to download OpenCode installer."
       INCOMPLETE=1
     elif ! verify_file_checksum "$opencode_install_script" "$OPENCODE_INSTALLER_SHA256"; then
diff --git a/scripts/init_system_readme.md b/scripts/init_system_readme.md
index bec1c08..de0c3dc 100644
--- a/scripts/init_system_readme.md
+++ b/scripts/init_system_readme.md
@@ -15,8 +15,8 @@ The script does not accept runtime arguments. Adjust defaults by editing constan
 ## What It Does
 
 - installs base tooling and `gh`
-- installs Node.js >= 20 (`npm`/`npx`)
-- installs `uv` and pre-downloads Python `3.10/3.11/3.12/3.13` (if missing)
+- installs Node.js >= 20 (`npm`/`npx`) from the distro package manager only
+- installs pinned `uv` release binaries and pre-downloads Python `3.10/3.11/3.12/3.13` (if missing)
 - creates shared directories and applies permissions
 - clones this repository to shared path (HTTPS by default)
 - creates A2A virtualenv via `uv sync --all-extras`
@@ -30,13 +30,30 @@ The script does not accept runtime arguments. Adjust defaults by editing constan
 - Toggles: `INSTALL_PACKAGES`, `INSTALL_UV`, `INSTALL_GH`, `INSTALL_NODE`
 - Versions: `NODE_MAJOR`, `UV_PYTHON_VERSIONS`
 - Installer pinning: `OPENCODE_INSTALLER_URL`, `OPENCODE_INSTALLER_VERSION`, `OPENCODE_INSTALLER_SHA256`, `OPENCODE_INSTALL_CMD`
+- uv release pinning: [`init_system_uv_release_manifest.sh`](./init_system_uv_release_manifest.sh)
+
+## Current Trust Model
+
+- `gh`: installed from distro package manager or package-manager-backed vendor repo configuration
+- Node.js: installed only from the distro package manager; the script no longer executes NodeSource setup scripts
+- `uv`: installed from a pinned upstream GitHub release tarball, with static asset/checksum data sourced from `init_system_uv_release_manifest.sh`
+- OpenCode: installer is still a remote script, but it is version-pinned and checksum-verified before execution
+- repo bootstrap: clone still trusts the configured git remote + branch head
 
 ## Recommended Secure Mode
 
 - keep installer pinning/checksum verification enabled
+- keep `init_system_uv_release_manifest.sh` aligned with the exact `uv` release assets you intend to trust
+- prefer distro package mirrors or internal mirrors for Node.js instead of adding ad-hoc third-party setup scripts
 - keep `/opt/uv-python` in controlled group mode (`770` -> `750` hardening flow)
 - set `UV_PYTHON_DIR_GROUP` to a controlled group and add runtime users intentionally
 
+## Failure Fallback
+
+- If `uv` bootstrap reports an unsupported Linux architecture/libc, install the pinned `uv` release manually and rerun `./scripts/init_system.sh` with `INSTALL_UV=false`.
+- If the distro package manager cannot provide `Node.js >= NODE_MAJOR`, install Node.js manually from a trusted distro or internal mirror and rerun with `INSTALL_NODE=false`.
+- If OpenCode installer checksum validation fails, stop and refresh the pinned installer metadata before retrying.
+
 ## Next Step
 
 After bootstrap, deploy a project instance with [`deploy_readme.md`](./deploy_readme.md).
diff --git a/scripts/init_system_uv_release_manifest.sh b/scripts/init_system_uv_release_manifest.sh
new file mode 100644
index 0000000..b964b02
--- /dev/null
+++ b/scripts/init_system_uv_release_manifest.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Pinned uv release assets used by scripts/init_system.sh.
+
+UV_VERSION="0.10.7"
+UV_RELEASE_BASE_URL="https://github.com/astral-sh/uv/releases/download/${UV_VERSION}"
+
+UV_TARBALL_X86_64_GNU="uv-x86_64-unknown-linux-gnu.tar.gz"
+UV_TARBALL_X86_64_GNU_SHA256="9ac6cee4e379a5abfca06e78a777b26b7ba1f81cb7935b97054d80d85ac00774" # pragma: allowlist secret
+
+UV_TARBALL_X86_64_MUSL="uv-x86_64-unknown-linux-musl.tar.gz"
+UV_TARBALL_X86_64_MUSL_SHA256="992529add6024e67135b1c80617abd2eca7be2cf0b99b3911f923de815bd8dc1" # pragma: allowlist secret
+
+UV_TARBALL_AARCH64_GNU="uv-aarch64-unknown-linux-gnu.tar.gz"
+UV_TARBALL_AARCH64_GNU_SHA256="20efc27d946860093650bcf26096a016b10fdaf03b13c33b75fbde02962beea9" # pragma: allowlist secret
+
+UV_TARBALL_AARCH64_MUSL="uv-aarch64-unknown-linux-musl.tar.gz"
+UV_TARBALL_AARCH64_MUSL_SHA256="115291f9943531a3b63db3a2eabda8b74b8da4831551679382cb309c9debd9f7" # pragma: allowlist secret
diff --git a/tests/test_init_system_security.py b/tests/test_init_system_security.py
index 427531e..f891e3a 100644
--- a/tests/test_init_system_security.py
+++ b/tests/test_init_system_security.py
@@ -3,21 +3,23 @@
 
 INIT_SYSTEM_PATH = Path("scripts/init_system.sh")
 INIT_SYSTEM_TEXT = INIT_SYSTEM_PATH.read_text()
+UV_MANIFEST_PATH = Path("scripts/init_system_uv_release_manifest.sh")
+UV_MANIFEST_TEXT = UV_MANIFEST_PATH.read_text()
 
 
-def _extract_var(var_name: str) -> str:
-    match = re.search(rf"^{var_name}=\"([^\"]*)\"", INIT_SYSTEM_TEXT, re.MULTILINE)
+def _extract_var(text: str, var_name: str) -> str:
+    match = re.search(rf"^{var_name}=\"([^\"]*)\"", text, re.MULTILINE)
     if not match:
-        msg = f"Missing constant {var_name} in scripts/init_system.sh"
+        msg = f"Missing constant {var_name}"
         raise AssertionError(msg)
     return match.group(1)
 
 
 def test_opencode_install_flow_is_pinned_and_verified() -> None:
-    url = _extract_var("OPENCODE_INSTALLER_URL")
-    version = _extract_var("OPENCODE_INSTALLER_VERSION")
-    checksum = _extract_var("OPENCODE_INSTALLER_SHA256")
-    install_cmd = _extract_var("OPENCODE_INSTALL_CMD")
+    url = _extract_var(INIT_SYSTEM_TEXT, "OPENCODE_INSTALLER_URL")
+    version = _extract_var(INIT_SYSTEM_TEXT, "OPENCODE_INSTALLER_VERSION")
+    checksum = _extract_var(INIT_SYSTEM_TEXT, "OPENCODE_INSTALLER_SHA256")
+    install_cmd = _extract_var(INIT_SYSTEM_TEXT, "OPENCODE_INSTALL_CMD")
 
     assert url == "https://opencode.ai/install"
     assert version
@@ -26,20 +28,47 @@ def test_opencode_install_flow_is_pinned_and_verified() -> None:
     assert "bash -" not in install_cmd
     assert "--version" in install_cmd
     assert "curl -fsSL https://opencode.ai/install | bash" not in INIT_SYSTEM_TEXT
-    assert 'download_script "$OPENCODE_INSTALLER_URL"' in INIT_SYSTEM_TEXT
+    assert 'source "${SCRIPT_DIR}/init_system_uv_release_manifest.sh"' in INIT_SYSTEM_TEXT
+    assert 'download_file "$OPENCODE_INSTALLER_URL"' in INIT_SYSTEM_TEXT
     assert (
         'verify_file_checksum "$opencode_install_script" "$OPENCODE_INSTALLER_SHA256"'
         in INIT_SYSTEM_TEXT
     )
 
 
+def test_uv_install_flow_is_pinned_to_release_tarballs() -> None:
+    version = _extract_var(UV_MANIFEST_TEXT, "UV_VERSION")
+    base_url = _extract_var(UV_MANIFEST_TEXT, "UV_RELEASE_BASE_URL")
+
+    assert re.fullmatch(r"[0-9]+\.[0-9]+\.[0-9]+", version)
+    assert base_url == "https://github.com/astral-sh/uv/releases/download/${UV_VERSION}"
+    assert "astral.sh/uv/install.sh" not in INIT_SYSTEM_TEXT
+    assert "install_uv_from_release" in INIT_SYSTEM_TEXT
+    assert "resolve_uv_release_artifact" in INIT_SYSTEM_TEXT
+    for checksum_var in (
+        "UV_TARBALL_X86_64_GNU_SHA256",
+        "UV_TARBALL_X86_64_MUSL_SHA256",
+        "UV_TARBALL_AARCH64_GNU_SHA256",
+        "UV_TARBALL_AARCH64_MUSL_SHA256",
+    ):
+        assert re.fullmatch(r"[0-9a-f]{64}", _extract_var(UV_MANIFEST_TEXT, checksum_var))
+
+
+def test_node_install_flow_avoids_remote_setup_scripts() -> None:
+    assert "deb.nodesource.com/setup_" not in INIT_SYSTEM_TEXT
+    assert "rpm.nodesource.com/setup_" not in INIT_SYSTEM_TEXT
+    assert "NodeSource setup script" not in INIT_SYSTEM_TEXT
+    assert "Installing Node.js from trusted package manager repositories" in INIT_SYSTEM_TEXT
+    assert "Install Node.js >= ${NODE_MAJOR} manually" in INIT_SYSTEM_TEXT
+
+
 def _parse_octal_mode(mode: str) -> int:
     return int(mode, 8)
 
 
 def test_uv_python_default_permissions_are_not_world_writable() -> None:
-    initial_mode = _extract_var("UV_PYTHON_DIR_MODE")
-    final_mode = _extract_var("UV_PYTHON_DIR_FINAL_MODE")
+    initial_mode = _extract_var(INIT_SYSTEM_TEXT, "UV_PYTHON_DIR_MODE")
+    final_mode = _extract_var(INIT_SYSTEM_TEXT, "UV_PYTHON_DIR_FINAL_MODE")
     mode_groups = _parse_octal_mode(initial_mode), _parse_octal_mode(final_mode)
     for mode in mode_groups:
         assert mode & 0o002 == 0