diff --git a/AGENTS.md b/AGENTS.md
index 082e0209..b3411d9a 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -29,6 +29,8 @@ Use these commands once the dev prerequisites above are satisfied.
 ```bash
 source .venv/bin/activate  # macOS/Linux
 uv pip install -r application/requirements.txt  # or: pip install -r application/requirements.txt
+# Optional docling parser engine (OCR / read_document structured output):
+# uv pip install -r application/requirements-docling.txt
 ```
 
 Run the API. For local dev, prefer the ASGI entrypoint under uvicorn — it
diff --git a/application/Dockerfile b/application/Dockerfile
index 18eb943c..e91839b0 100644
--- a/application/Dockerfile
+++ b/application/Dockerfile
@@ -28,8 +28,8 @@ RUN wget -q -O - https://sh.rustup.rs | sh -s -- -y
 # Clean up to reduce container size
 RUN apt-get remove --purge -y wget unzip && apt-get autoremove -y && rm -rf /var/lib/apt/lists/*
 
-# Copy requirements.txt
-COPY requirements.txt .
+# Copy requirements manifests
+COPY requirements.txt requirements-docling.txt ./
 
 # Setup Python virtual environment
 RUN python3.12 -m venv /venv
@@ -42,6 +42,15 @@ RUN pip install --no-cache-dir --upgrade pip && \
     pip install --no-cache-dir tiktoken && \
     pip install --no-cache-dir -r requirements.txt
 
+# Optional docling parser engine (DOC_PARSER_ENGINE=docling, OCR for scanned
+# PDFs/images, read_document's structured output) — OFF by default: it pulls
+# the layout/OCR model stack and adds gigabytes to the image. anydoc (in
+# requirements.txt) is the default parser and needs none of it.
+ARG INSTALL_DOCLING=false
+RUN if [ "$INSTALL_DOCLING" = "true" ]; then \
+        pip install --no-cache-dir -r requirements-docling.txt; \
+    fi
+
 # Final Stage
 FROM ubuntu:24.04 as final
 
diff --git a/application/requirements-docling.txt b/application/requirements-docling.txt
new file mode 100644
index 00000000..07dd1074
--- /dev/null
+++ b/application/requirements-docling.txt
@@ -0,0 +1,14 @@
+# Optional docling parser engine.
+#
+# Needed only for: DOC_PARSER_ENGINE=docling, OCR of scanned PDFs and images
+# (DOCLING_OCR_ENABLED / DOCLING_OCR_ATTACHMENTS_ENABLED), .adoc/.vtt/.xml
+# source parsing, and the read_document tool's `structured` output. The
+# default anydoc engine needs none of this.
+#
+# Install ON TOP of requirements.txt (torch/transformers stay pinned there,
+# shared with sentence-transformers):
+#   pip install -r requirements.txt -r requirements-docling.txt
+# Docker: build with --build-arg INSTALL_DOCLING=true
+docling==2.119.0
+rapidocr==3.9.2
+onnxruntime==1.28.0
diff --git a/application/requirements.txt b/application/requirements.txt
index 98c6b536..cb359123 100644
--- a/application/requirements.txt
+++ b/application/requirements.txt
@@ -12,12 +12,10 @@ cryptography==50.0.0
 dataclasses-json==0.6.7
 daytona==0.205.1
 defusedxml==0.7.1
-docling==2.119.0
-# Default document converter (DOC_PARSER_ENGINE=anydoc); docling above is
-# the optional heavy engine for OCR/structured output.
+# Default document converter (DOC_PARSER_ENGINE=anydoc). The docling engine
+# (OCR, layout/table models, read_document's structured output) is an
+# optional extra: pip install -r requirements-docling.txt
 firecrawl-anydoc==0.2.3
-rapidocr==3.9.2
-onnxruntime==1.28.0
 docx2txt==0.9
 ddgs>=8.0.0
 fast-ebook
@@ -98,10 +96,14 @@ sqlalchemy>=2.0,<3
 starlette>=1.0,<2
 tiktoken==0.13.0
 tokenizers==0.22.2
+# torch stays in core: sentence-transformers (local embeddings) needs it even
+# with the docling extra uninstalled.
 torch==2.11.0
 tqdm==4.67.3
-# Capped <5.9.0 to match docling-core's own darwin pin: 5.9+ breaks docling's
-# PDF layout model on Apple Silicon ("Cannot convert a MPS Tensor to float64").
+# Kept in core for sentence-transformers, so installing the optional docling
+# extra never changes the shared model stack. Capped <5.9.0 to match
+# docling-core's own darwin pin: 5.9+ breaks docling's PDF layout model on
+# Apple Silicon ("Cannot convert a MPS Tensor to float64").
 transformers==5.8.1
 typing-extensions==4.16.0
 typing-inspect==0.9.0
diff --git a/deployment/docker-compose.yaml b/deployment/docker-compose.yaml
index b027ac1a..d1dfc7c4 100644
--- a/deployment/docker-compose.yaml
+++ b/deployment/docker-compose.yaml
@@ -15,7 +15,12 @@ services:
 
   backend:
     user: root
-    build: ../application
+    build:
+      context: ../application
+      args:
+        # Bake the optional docling engine (OCR, structured output) into the
+        # image: set INSTALL_DOCLING=true in ../.env or the shell.
+        INSTALL_DOCLING: ${INSTALL_DOCLING:-false}
     env_file:
       - ../.env
     environment:
@@ -38,7 +43,10 @@ services:
 
   worker:
     user: root
-    build: ../application
+    build:
+      context: ../application
+      args:
+        INSTALL_DOCLING: ${INSTALL_DOCLING:-false}
     # Consumes the default queue AND the dedicated `parsing` queue (read_document /
     # parse_document). Without `parsing` here the read_document await never resolves.
     # For heavy/OCR parsing run a separate worker with `-Q parsing`.
diff --git a/docs/content/Deploying/Development-Environment.mdx b/docs/content/Deploying/Development-Environment.mdx
index b94e8056..0a6a6bbf 100644
--- a/docs/content/Deploying/Development-Environment.mdx
+++ b/docs/content/Deploying/Development-Environment.mdx
@@ -96,6 +96,13 @@ To run the DocsGPT backend locally, you'll need to set up a Python environment a
     pip install -r application/requirements.txt
     ```
 
+    Optionally add the docling parser engine (OCR, `structured` output for
+    `read_document`; the default anydoc engine does not need it):
+
+    ```bash
+    pip install -r application/requirements-docling.txt
+    ```
+
 5.  **Run the Backend:**
 
     For local development, run the ASGI composition under uvicorn. It serves the **whole** application, hot-reloads on source changes, and matches the production runtime:
diff --git a/docs/content/Deploying/DocsGPT-Settings.mdx b/docs/content/Deploying/DocsGPT-Settings.mdx
index f344edac..cc10e7a0 100644
--- a/docs/content/Deploying/DocsGPT-Settings.mdx
+++ b/docs/content/Deploying/DocsGPT-Settings.mdx
@@ -206,7 +206,7 @@ for the engines and flows.
 
 | Setting | Default | Description |
 | --- | --- | --- |
-| `DOC_PARSER_ENGINE` | `anydoc` | Parser engine: `anydoc` (fast Rust converter, no ML models) or `docling` (layout/table models, OCR, structured output; heavy optional install). Files anydoc cannot read fall back to Docling when installed. |
+| `DOC_PARSER_ENGINE` | `anydoc` | Parser engine: `anydoc` (fast Rust converter, no ML models) or `docling` (layout/table models, OCR, structured output). Files anydoc cannot read fall back to Docling when installed. Docling is an optional extra: `pip install -r application/requirements-docling.txt`, or Docker builds with `--build-arg INSTALL_DOCLING=true`. |
 | `DOCLING_OCR_ENABLED` | `false` | OCR for source ingestion (Docling only). |
 | `DOCLING_OCR_ATTACHMENTS_ENABLED` | `false` | OCR for chat attachments (Docling only). |
 | `ATTACHMENT_PDF_TEXT_FAST_PATH` | `true` | Under the `docling` engine, read PDF attachments through their text layer (pypdfium2) and only hand scans to Docling. Not needed under `anydoc`. |
diff --git a/docs/content/Guides/ocr.mdx b/docs/content/Guides/ocr.mdx
index 3109ac52..16aec08d 100644
--- a/docs/content/Guides/ocr.mdx
+++ b/docs/content/Guides/ocr.mdx
@@ -41,6 +41,29 @@ sources, and the fallback for files anydoc rejects. Without Docling those
 formats use the standard parsers, and images are only read when
 `PARSE_IMAGE_REMOTE=true`.
 
+## Installing the docling engine
+
+docling is not part of the base install. Add it when you need OCR,
+`.adoc`/`.vtt`/`.xml` source parsing, or `read_document`'s `structured`
+output:
+
+```bash
+pip install -r application/requirements-docling.txt
+```
+
+Docker images build without it by default; opt in with the build argument:
+
+```bash
+docker build --build-arg INSTALL_DOCLING=true ./application
+```
+
+`deployment/docker-compose.yaml` forwards the same switch, so setting
+`INSTALL_DOCLING=true` in `.env` (or the shell) bakes docling into locally
+built backend and worker images. `setup.sh` writes it automatically when you
+answer yes to the OCR question. Either way no code changes are needed —
+docling is picked up as the fallback engine as soon as it is importable, and
+`DOC_PARSER_ENGINE=docling` makes it the primary one.
+
 ## Docling OCR
 
 OCR is optional, Docling-only, and controlled by two settings:
diff --git a/setup.sh b/setup.sh
index e98a6e0b..310267ef 100755
--- a/setup.sh
+++ b/setup.sh
@@ -365,7 +365,10 @@ configure_doc_processing() {
     read -p "$(echo -e "${DEFAULT_FG}Enable OCR for document processing (Docling)? (y/N): ${NC}")" ocr_enabled
     if [[ "$ocr_enabled" =~ ^[yY]$ ]]; then
         echo "DOCLING_OCR_ENABLED=true" >> "$ENV_FILE"
-        echo -e "${GREEN}Docling OCR enabled.${NC}"
+        # OCR needs the optional docling engine; locally built images include
+        # it via this build arg (hub images must be published with it baked in).
+        echo "INSTALL_DOCLING=true" >> "$ENV_FILE"
+        echo -e "${GREEN}Docling OCR enabled (locally built images will include the docling engine).${NC}"
     fi
 }
 
diff --git a/tests/parser/file/test_docling_parser.py b/tests/parser/file/test_docling_parser.py
index 7fa3eba0..a7825c9e 100644
--- a/tests/parser/file/test_docling_parser.py
+++ b/tests/parser/file/test_docling_parser.py
@@ -910,6 +910,12 @@ class TestApplyInferenceSettings:
     and buys nothing for one-shot parses.
     """
 
+    @pytest.fixture(autouse=True)
+    def _requires_docling(self):
+        # These tests reach into docling.datamodel.settings for real; a base
+        # install (docling is an optional extra) skips them.
+        pytest.importorskip("docling")
+
     def test_disables_torch_compile_by_default(self, monkeypatch):
         from application.parser.file.docling_parser import _apply_inference_settings
 
@@ -1412,6 +1418,12 @@ class TestOCRDropoutHelpers:
 class TestForceFullPageOCRWiring:
     """``force_full_page_ocr`` must reach the pipeline for any OCR engine."""
 
+    @pytest.fixture(autouse=True)
+    def _requires_docling(self):
+        # Builds real ``docling.datamodel.pipeline_options``; a base install
+        # (docling is an optional extra) skips these.
+        pytest.importorskip("docling")
+
     def _pipeline_options(self, monkeypatch, **kwargs):
         import docling.datamodel.pipeline_options as dpo
 
diff --git a/tests/parser/file/test_pdfium_parser.py b/tests/parser/file/test_pdfium_parser.py
index 22b44848..d3dc9f40 100644
--- a/tests/parser/file/test_pdfium_parser.py
+++ b/tests/parser/file/test_pdfium_parser.py
@@ -158,6 +158,10 @@ def test_threshold_sends_sparse_text_to_fallback(tmp_path, parser_cls):
 
 @pytest.fixture
 def docling_engine(monkeypatch):
+    # The wiring assertions below expect the docling map; on a base install
+    # (docling is an optional extra) the engine degrades to the legacy
+    # parsers and these tests do not apply.
+    pytest.importorskip("docling")
     from application.core.settings import settings
 
     monkeypatch.setattr(settings, "DOC_PARSER_ENGINE", "docling")
diff --git a/tests/requirements.txt b/tests/requirements.txt
index 72ddee03..806be501 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -12,3 +12,6 @@ jupyter-client>=8.0
 # (python-pptx and openpyxl already ship in application/requirements.txt).
 python-docx>=1.1
 reportlab>=4.0,<5
+# The optional docling engine stays installed in the test env so its parser
+# paths keep CI coverage even though production installs it on demand.
+-r ../application/requirements-docling.txt