diff --git a/Dockerfile b/Dockerfile
index 535f0a0..ad273ce 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,9 +22,12 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 WORKDIR /app
 
-# Install Python deps first (layer cache)
-COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt
+# Install Python deps first (layer cache). Optional extras (PyMuPDF AGPL, etc.)
+# are opt-in so the default image stays MIT-core; see requirements-optional.txt.
+ARG INSTALL_OPTIONAL=false
+COPY requirements.txt requirements-optional.txt ./
+RUN pip install --no-cache-dir -r requirements.txt \
+    && if [ "$INSTALL_OPTIONAL" = "true" ]; then pip install --no-cache-dir -r requirements-optional.txt; fi
 
 # Copy app code
 COPY . .
diff --git a/README.md b/README.md
index d720ec0..638089f 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,8 @@ cd odysseus
 cp .env.example .env       # optional, but recommended for explicit defaults
 docker compose up -d --build
 ```
+To include optional extras in the image (PDF viewer, Office extraction; includes AGPL PyMuPDF), build with `docker compose build --build-arg INSTALL_OPTIONAL=true` before `up`.
+
 Open `http://localhost:7000` when the containers are healthy. Docker Compose
 binds the web UI to `127.0.0.1` by default. If the port is taken, set
 `APP_PORT=7001` in `.env` and recreate the container. Set `APP_BIND=0.0.0.0`