diff --git a/debian13/Dockerfile b/debian13/Dockerfile
index 6a832e5..77a41e6 100644
--- a/debian13/Dockerfile
+++ b/debian13/Dockerfile
@@ -824,3 +824,13 @@ RUN mkdir -p ${PREFIX}/share/source-stack \
     && sed "s|@MULTIARCH@|$(gcc -dumpmachine)|" /tmp/source-stack.cmake.in \
         > ${PREFIX}/share/source-stack/source-stack.cmake \
     && rm /tmp/source-stack.cmake.in
+
+RUN useradd --create-home develop
+USER develop
+
+ENV CLAUDE_CONFIG_DIR="$HOME/my-claude"
+ENV DISABLE_AUTOUPDATER="1"
+RUN bash -c 'curl -fsSL https://claude.ai/install.sh | bash'
+
+ARG CLAUDE_CODE_OAUTH_TOKEN
+ENV CLAUDE_CODE_OAUTH_TOKEN=${CLAUDE_CODE_OAUTH_TOKEN}
diff --git a/debian13/build.sh b/debian13/build.sh
index d9c50bf..a597409 100755
--- a/debian13/build.sh
+++ b/debian13/build.sh
@@ -1,10 +1,38 @@
 #!/bin/sh
+# Usage:
+#   ./build.sh            build the image, asking for the password that unlocks the token
+#   ./build.sh --encrypt  encrypt a token and print the value to paste into ENCRYPTED_TOKEN
 
 set -eu
 
 IMAGE_NAME="${IMAGE_NAME:-debian13-source-stack}"
 PREFIX="${PREFIX:-/opt/local}"
 SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
+
+# CLAUDE_CODE_OAUTH_TOKEN encrypted with AES-256-CBC (PBKDF2, base64). Generate with --encrypt.
+ENCRYPTED_TOKEN='U2FsdGVkX1/BCTASs0tR40hsT+sngp46zANCbGZnklLN1M0wSJs/DxbQ6JDg593G09A+cVtVius4hJHRzB6caOO2KwBV0/+i7yUjr/PfreZksrdkz1DnFc7oorxXfvB7azuNEkQfAE2fZg8cnYL5jy3/LKRdAm11SUm83fU8ke8='
+
+OPENSSL_ARGS="enc -aes-256-cbc -pbkdf2 -iter 600000 -a -A"
+
+if ! command -v openssl >/dev/null 2>&1; then
+    echo "Error: OpenSSL is required." >&2
+    exit 1
+fi
+
+# read_secret PROMPT VARNAME: read the input with echo on, so it stays visible while typing.
+read_secret() {
+    printf '%s' "$1" >&2
+    IFS= read -r "$2"
+}
+
+if [ "${1:-}" = "--encrypt" ]; then
+    read_secret "OAuth token: " token
+    read_secret "Password: " BUILD_PASSWORD
+    export BUILD_PASSWORD
+    printf '%s' "$token" | openssl $OPENSSL_ARGS -pass env:BUILD_PASSWORD
+    echo
+    exit 0
+fi
 SOURCES_DIR="${SOURCES_DIR:-$SCRIPT_DIR/../sources}"
 FETCH_SCRIPT="$SCRIPT_DIR/../fetch-sources.sh"
 
@@ -13,6 +41,22 @@ if ! command -v podman >/dev/null 2>&1; then
     exit 1
 fi
 
+if [ -z "$ENCRYPTED_TOKEN" ]; then
+    echo "Error: ENCRYPTED_TOKEN is empty; run './build.sh --encrypt' and paste the output into build.sh." >&2
+    exit 1
+fi
+
+read_secret "Password for CLAUDE_CODE_OAUTH_TOKEN: " BUILD_PASSWORD
+export BUILD_PASSWORD
+if ! CLAUDE_CODE_OAUTH_TOKEN=$(printf '%s' "$ENCRYPTED_TOKEN" | openssl $OPENSSL_ARGS -d -pass env:BUILD_PASSWORD 2>/dev/null); then
+    echo "Error: wrong password or corrupted token." >&2
+    exit 1
+fi
+unset BUILD_PASSWORD
+
+# Exported so podman reads the value from the environment and it never appears in the command line.
+export CLAUDE_CODE_OAUTH_TOKEN
+
 SOURCES_DIR="$SOURCES_DIR" "$FETCH_SCRIPT"
 
 # macOS reports arm64 where Linux (and Debian multiarch) call it aarch64.
@@ -20,6 +64,8 @@ ARCH=$(uname -m)
 [ "$ARCH" = arm64 ] && ARCH=aarch64
 
 echo "Building image $IMAGE_NAME with podman (prefix $PREFIX) ..."
-exec podman build --build-context sources="$SOURCES_DIR" \
+exec podman build \
+    --build-arg CLAUDE_CODE_OAUTH_TOKEN \
+    --build-context sources="$SOURCES_DIR" \
     --build-arg PREFIX="$PREFIX" --build-arg MULTIARCH="$ARCH-linux-gnu" \
     --tag "$IMAGE_NAME" "$SCRIPT_DIR"