diff --git a/.agents/skills/pdfrest-client-api/SKILL.md b/.agents/skills/pdfrest-client-api/SKILL.md
index bea4c5ca..df05bb34 100644
--- a/.agents/skills/pdfrest-client-api/SKILL.md
+++ b/.agents/skills/pdfrest-client-api/SKILL.md
@@ -181,6 +181,68 @@ Follow `TESTING_GUIDELINES.md` and the live-test requirements in `AGENTS.md`.
 - Update the API guide, public exports, and user-facing examples when the new
   capability or parameter changes discoverability or usage.
 
+### Runnable example requirement
+
+Every new public endpoint/helper requires a runnable example; it is part of the
+API deliverable, not optional follow-up documentation. For a compatible change
+to an existing helper, extend or add an example when the new parameter changes a
+user workflow or demonstrates behavior that is not otherwise discoverable.
+
+- Before creating the example, identify every input asset it needs and inspect
+  `examples/resources/` for a suitable deterministic, redistributable fixture.
+  If any required file is absent, ask the user to provide it, naming the needed
+  file type and relevant characteristics (for example, a signed PDF, a
+  multi-page TIFF, a font, or a profile JSON). Do not fabricate, download, or
+  substitute a semantically unsuitable input. Stop if a required fixture cannot
+  be obtained.
+
+- Add one endpoint-oriented script at
+  `examples/<capability>/<descriptive_name>_example.py` and list it in
+  `examples/README.md`. Reuse checked-in assets via a path derived from
+  `Path(__file__)`; place an approved new shared asset under
+  `examples/resources/`.
+
+- Start the script at line one with the repository's single-line PEP 723 header:
+
+  ```python
+  # /// script
+  # requires-python = ">=3.10"
+  # dependencies = ["pdfrest", "python-dotenv"]
+  # ///
+  ```
+
+  Adjust the Python constraint and declare every third-party import. Do not add
+  a shebang before the metadata. Inline metadata isolates `uv run` from the
+  project environment, and `noxfile.py` parses this exact line-one structure.
+
+- Immediately follow the header with a module docstring that explains the user
+  outcome, enumerates the upload/API/result steps, names `PDFREST_API_KEY` and
+  all input prerequisites, and provides the repository-root command
+  `uv run examples/<capability>/<descriptive_name>_example.py`.
+
+- Use the public SDK exactly as a customer would: load the API key environment,
+  enter the sync or async client context manager, upload local assets first,
+  call the new helper with `PdfRestFile` values, and print concise,
+  endpoint-relevant response details. Keep it deterministic, repeatable, and
+  independent of third-party URLs.
+
+- When a public `TypedDict` represents a structured API input, construct it in
+  examples with its keyword constructor, such as `PdfAddLineObject(...)`,
+  instead of an anonymous dictionary literal. Annotate heterogeneous collections
+  with the public union alias, such as `list[PdfAddShapeObject]`. Reserve
+  dictionary literals for dynamic data, intentionally invalid input, and raw
+  wire-format overrides.
+
+- Use `python-X.Y/<same_name>.py` plus an extending `ruff.toml` only when an
+  older interpreter needs a distinct implementation. Otherwise keep one script
+  compatible across the supported range.
+
+- Validate the example against the local checkout with
+  `uvx nox -s run-example -- examples/<capability>/<script>.py`. When practical,
+  run `uvx nox -s examples` to cover Python 3.10-3.14; direct
+  `uv run examples/<capability>/<script>.py` is also required once the published
+  `pdfrest` release contains the new API.
+
 ### Generated API-reference contracts
 
 The API reference is generated from the public source. Keep request-shape
@@ -210,6 +272,6 @@ documentation with its types; do not hand-copy a shape schema into Markdown.
 
 Run targeted unit and live tests first, then the relevant Ruff and type checks.
 Run the full pytest suite and `uvx nox -s tests` when practical. For API
-reference changes, also run the strict docs build. Report the OpenAPI operation
-inspected, files changed, checks run, checks skipped, and any live-validation
-limitation.
+reference changes, also run the strict docs build. Run the focused example and
+the example matrix as described above. Report the OpenAPI operation inspected,
+files changed, checks run, checks skipped, and any live-validation limitation.
diff --git a/AGENTS.md b/AGENTS.md
index 44572315..7bdf2d02 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -326,6 +326,73 @@
   to `.env`) in temporary scripts to drive the in-flight client against live
   endpoints and capture responses for test data and assertions.
 
+## Example Guidelines
+
+- Every new public endpoint/helper must include a runnable example under
+  `examples/`. Group examples by capability in an endpoint-oriented directory
+  such as `examples/extract_text/`, and use a descriptive `*_example.py`
+  filename. Add the script to the inventory in `examples/README.md` and update
+  relevant docs links or usage guidance when the new capability changes
+  discoverability.
+
+- Make each example a standalone uv script. Its first lines must be a PEP 723
+  metadata block in the single-line form understood by the Nox example discovery
+  code:
+
+  ```python
+  # /// script
+  # requires-python = ">=3.10"
+  # dependencies = ["pdfrest", "python-dotenv"]
+  # ///
+  ```
+
+  Set `requires-python` to the widest supported range the example actually
+  supports and list every third-party import in `dependencies`. Keep the block
+  first (do not put a shebang above it), because `noxfile.py` reads metadata
+  starting at line one. PEP 723 metadata gives `uv run` an isolated environment;
+  do not rely on undeclared project or development dependencies.
+
+- Follow the metadata with a module docstring that states the user outcome,
+  lists the important upload/API/output steps, and gives the exact command to
+  run from the repository root, for example
+  `uv run examples/extract_text/extract_pdf_text_example.py`. Name required
+  environment variables, input files, and any expected setup in that docstring.
+
+- Prefer deterministic, redistributable inputs under `examples/resources/` and
+  resolve them relative to `Path(__file__)`, never the caller's working
+  directory. Reuse a suitable checked-in resource when possible. Before adding a
+  new binary or specialized input, confirm its provenance, redistribution
+  suitability, and expected API behavior; ask the contributor for the required
+  asset when those cannot be established.
+
+- Examples exercise the real service, load `PDFREST_API_KEY` from the
+  environment (optionally through `python-dotenv`), upload local inputs through
+  `client.files.create_from_paths`, and use client context managers. Keep the
+  flow short and instructional while printing enough typed response data for a
+  user and CI to confirm success.
+
+- When a public `TypedDict` represents a structured API input, construct it in
+  examples with its keyword constructor, such as `PdfAddLineObject(...)`,
+  instead of an anonymous dictionary literal. Annotate heterogeneous collections
+  with the public union alias, such as `list[PdfAddShapeObject]`, so readers and
+  type checkers can see the supported contract. Use dictionary literals when
+  demonstrating dynamic data, intentionally invalid input, or raw wire-format
+  overrides.
+
+- Put interpreter-specific alternatives beside the base script as
+  `python-X.Y/<same_name>.py`, with a local `ruff.toml` extending the parent
+  configuration, only when syntax or compatibility requires a distinct script.
+  The base script remains the default for newer supported interpreters.
+
+- Validate a new or changed example directly with `uv run <script>` when the
+  published SDK contains the demonstrated API. During development, validate
+  against the local checkout with
+  `uvx nox -s run-example -- examples/<capability>/<script>.py`; run
+  `uvx nox -s examples` for the Python 3.10-3.14 matrix when practical. The CI
+  `examples` job runs every discovered script against the live service on each
+  supported interpreter and gates publishing, so examples must be safe to run
+  repeatedly and must not depend on third-party network resources.
+
 ## Commit & Pull Request Guidelines
 
 - Follow the `area: summary` convention seen in `pdfassistant-chatbot` (e.g.,
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 98d8c17d..d07e947b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -78,6 +78,22 @@ To reuse existing coverage JSON without rerunning tests:
 uvx nox -s class-coverage -- --no-tests
 ```
 
+### Live tests
+
+Live tests require `PDFREST_API_KEY`. By default, the test fixture tries the
+local service, the development service, and then the production service. To run
+against a specific reachable pdfRest deployment first, set
+`PDFREST_LIVE_BASE_URL` to its base URL:
+
+```bash
+export PDFREST_API_KEY="..."
+export PDFREST_LIVE_BASE_URL="https://pdfrest.example.com"
+uvx nox -s tests-3.11 -- tests/live
+```
+
+If that URL is unavailable, the fixture continues with its normal fallback URLs
+and fails only when none are reachable.
+
 ## Examples
 
 Run all examples:
diff --git a/docs/api-guide.md b/docs/api-guide.md
index 838170f5..aacfafad 100644
--- a/docs/api-guide.md
+++ b/docs/api-guide.md
@@ -81,7 +81,8 @@ Use this group to add visible content or remove sensitive content.
 
 - Add overlays:
   [add_text_to_pdf][pdfrest.PdfRestClient.add_text_to_pdf],
-  [add_image_to_pdf][pdfrest.PdfRestClient.add_image_to_pdf]
+  [add_image_to_pdf][pdfrest.PdfRestClient.add_image_to_pdf],
+  [add_shapes_to_pdf][pdfrest.PdfRestClient.add_shapes_to_pdf]
 - Watermarking:
   [watermark_pdf_with_text][pdfrest.PdfRestClient.watermark_pdf_with_text],
   [watermark_pdf_with_image][pdfrest.PdfRestClient.watermark_pdf_with_image]
diff --git a/examples/README.md b/examples/README.md
index 76571230..b3089918 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -21,6 +21,8 @@ supported interpreter matrix.
 
 ## Available Examples
 
+- `examples/add_shapes/add_shapes_to_pdf_example.py` – add a styled rectangle
+  and divider line to a PDF with accessibility tagging enabled.
 - `examples/delete/delete_example.py` – demonstrate file deletion (sync + async
   variants).
 - `examples/extract_text/extract_pdf_text_example.py` – run `extract_pdf_text`
diff --git a/examples/add_shapes/add_shapes_to_pdf_example.py b/examples/add_shapes/add_shapes_to_pdf_example.py
new file mode 100644
index 00000000..f527ea94
--- /dev/null
+++ b/examples/add_shapes/add_shapes_to_pdf_example.py
@@ -0,0 +1,83 @@
+# /// script
+# requires-python = ">=3.10"
+# dependencies = ["pdfrest", "python-dotenv"]
+# ///
+"""Add a styled panel and divider line to a PDF.
+
+This sample demonstrates how to:
+
+1. Upload the bundled ``examples/resources/report.pdf`` resource.
+2. Describe rectangle and line overlays with typed ``PdfAddShapeObject`` values.
+3. Add the shapes to page 1 with accessibility tagging enabled.
+4. Print metadata for the PDF returned by pdfRest.
+
+Set ``PDFREST_API_KEY``, then run from the repository root with
+``uv run examples/add_shapes/add_shapes_to_pdf_example.py``. The input PDF is
+included in the repository, so no additional input files are required.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from dotenv import load_dotenv
+
+from pdfrest import PdfRestClient
+from pdfrest.types import (
+    PdfAddLineObject,
+    PdfAddRectangleObject,
+    PdfAddShapeObject,
+)
+
+RESOURCE = Path(__file__).resolve().parents[1] / "resources" / "report.pdf"
+
+
+def add_shapes_to_report() -> None:
+    """Upload the sample report and add a tagged panel and divider line."""
+    load_dotenv()
+    shapes: list[PdfAddShapeObject] = [
+        PdfAddRectangleObject(
+            type="rectangle",
+            page=1,
+            x=54,
+            y=540,
+            width=504,
+            height=108,
+            fill_color=(245, 247, 250),
+            stroke_color=(26, 72, 112),
+            stroke_width=1,
+            tag_is_artifact=True,
+        ),
+        PdfAddLineObject(
+            type="line",
+            page=1,
+            x1=72,
+            y1=510,
+            x2=540,
+            y2=510,
+            stroke_color=(220, 45, 55),
+            stroke_width=4,
+            tag_actual_text="Report section divider",
+            tag_structure_type="Figure",
+        ),
+    ]
+
+    with PdfRestClient() as client:
+        uploaded = client.files.create_from_paths([RESOURCE])[0]
+        response = client.add_shapes_to_pdf(
+            uploaded,
+            shape_objects=shapes,
+            tag_enabled=True,
+            output="report-with-shapes",
+        )
+
+    output = response.output_file
+    print(f"Created {output.name}")
+    print(f"Output ID: {output.id}")
+    print(f"MIME type: {output.type}")
+    print(f"Size: {output.size} bytes")
+    print(f"Download URL: {output.url}")
+
+
+if __name__ == "__main__":  # pragma: no cover - manual example
+    add_shapes_to_report()
diff --git a/pyproject.toml b/pyproject.toml
index c744ad1a..2bdc5ded 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "pdfrest"
-version = "1.0.4"
+version = "1.1.0"
 description = "Python client library for interacting with the pdfRest API"
 readme = {file = "README.md", content-type = "text/markdown"}
 authors = [
diff --git a/src/pdfrest/client.py b/src/pdfrest/client.py
index 7c66e190..dd1cc72b 100644
--- a/src/pdfrest/client.py
+++ b/src/pdfrest/client.py
@@ -91,6 +91,7 @@
     OcrPdfPayload,
     PdfAddAttachmentPayload,
     PdfAddImagePayload,
+    PdfAddShapesPayload,
     PdfAddTextPayload,
     PdfBlankPayload,
     PdfCompressPayload,
@@ -144,6 +145,7 @@
     HtmlWebLayout,
     JpegColorModel,
     OcrLanguage,
+    PdfAddShapeObject,
     PdfAddTextObject,
     PdfAType,
     PdfConversionCompression,
@@ -3453,6 +3455,59 @@ def add_text_to_pdf(
             timeout=timeout,
         )
 
+    def add_shapes_to_pdf(
+        self,
+        file: PdfRestFile | Sequence[PdfRestFile],
+        *,
+        shape_objects: PdfAddShapeObject | Sequence[PdfAddShapeObject],
+        tag_enabled: bool | None = None,
+        output: str | None = None,
+        extra_query: Query | None = None,
+        extra_headers: AnyMapping | None = None,
+        extra_body: Body | None = None,
+        timeout: TimeoutTypes | None = None,
+    ) -> PdfRestFileBasedResponse:
+        """Draw one or more lines or rectangles onto a PDF.
+
+        Coordinates use PDF units with the origin in the lower-left corner.
+        Set ``tag_enabled=True`` when any shape includes tagging metadata.
+
+        Args:
+            file: Uploaded PDF file as a `PdfRestFile` object.
+            shape_objects: Line or rectangle objects to draw onto the document.
+            tag_enabled: Enable tagging for newly added shapes.
+            output: Output filename prefix used by pdfRest when creating files.
+            extra_query: Additional query parameters merged into the request.
+            extra_headers: Additional HTTP headers merged into the request.
+            extra_body: Additional request body fields merged into the payload.
+            timeout: Request timeout override for this call.
+
+        Returns:
+            Validated file-based response returned by pdfRest.
+
+        Raises:
+            PdfRestError: If request execution fails at the client or API layer.
+            ValidationError: If local payload validation fails before sending.
+        """
+        payload: dict[str, Any] = {
+            "files": file,
+            "shape_objects": shape_objects,
+        }
+        if tag_enabled is not None:
+            payload["tag_enabled"] = tag_enabled
+        if output is not None:
+            payload["output"] = output
+
+        return self._post_file_operation(
+            endpoint="/pdf-with-added-shapes",
+            payload=payload,
+            payload_model=PdfAddShapesPayload,
+            extra_query=extra_query,
+            extra_headers=extra_headers,
+            extra_body=extra_body,
+            timeout=timeout,
+        )
+
     def add_image_to_pdf(
         self,
         file: PdfRestFile | Sequence[PdfRestFile],
@@ -6448,6 +6503,59 @@ async def add_text_to_pdf(
             timeout=timeout,
         )
 
+    async def add_shapes_to_pdf(
+        self,
+        file: PdfRestFile | Sequence[PdfRestFile],
+        *,
+        shape_objects: PdfAddShapeObject | Sequence[PdfAddShapeObject],
+        tag_enabled: bool | None = None,
+        output: str | None = None,
+        extra_query: Query | None = None,
+        extra_headers: AnyMapping | None = None,
+        extra_body: Body | None = None,
+        timeout: TimeoutTypes | None = None,
+    ) -> PdfRestFileBasedResponse:
+        """Asynchronous variant of [PdfRestClient.add_shapes_to_pdf][pdfrest.PdfRestClient.add_shapes_to_pdf].
+
+        Coordinates use PDF units with the origin in the lower-left corner.
+        Set ``tag_enabled=True`` when any shape includes tagging metadata.
+
+        Args:
+            file: Uploaded PDF file as a `PdfRestFile` object.
+            shape_objects: Line or rectangle objects to draw onto the document.
+            tag_enabled: Enable tagging for newly added shapes.
+            output: Output filename prefix used by pdfRest when creating files.
+            extra_query: Additional query parameters merged into the request.
+            extra_headers: Additional HTTP headers merged into the request.
+            extra_body: Additional request body fields merged into the payload.
+            timeout: Request timeout override for this call.
+
+        Returns:
+            Validated file-based response returned by pdfRest.
+
+        Raises:
+            PdfRestError: If request execution fails at the client or API layer.
+            ValidationError: If local payload validation fails before sending.
+        """
+        payload: dict[str, Any] = {
+            "files": file,
+            "shape_objects": shape_objects,
+        }
+        if tag_enabled is not None:
+            payload["tag_enabled"] = tag_enabled
+        if output is not None:
+            payload["output"] = output
+
+        return await self._post_file_operation(
+            endpoint="/pdf-with-added-shapes",
+            payload=payload,
+            payload_model=PdfAddShapesPayload,
+            extra_query=extra_query,
+            extra_headers=extra_headers,
+            extra_body=extra_body,
+            timeout=timeout,
+        )
+
     async def add_image_to_pdf(
         self,
         file: PdfRestFile | Sequence[PdfRestFile],
diff --git a/src/pdfrest/models/_internal.py b/src/pdfrest/models/_internal.py
index 50d434e4..8a72654e 100644
--- a/src/pdfrest/models/_internal.py
+++ b/src/pdfrest/models/_internal.py
@@ -29,6 +29,7 @@
     HtmlWebLayout,
     OcrLanguage,
     PdfAType,
+    PdfContentStructureType,
     PdfConversionCompression,
     PdfConversionDownsample,
     PdfConversionLocale,
@@ -135,8 +136,9 @@ def _split_comma_string(value: Any) -> list[Any] | None:
     raise ValueError(msg)
 
 
-def _route_text_color_by_channel_count(
+def _route_color_by_channel_count(
     *,
+    color_name: str,
     expected_channel_count: int,
     alternate_channel_count: int,
 ) -> Callable[[Any], list[Any] | None]:
@@ -148,7 +150,7 @@ def _validator(value: Any) -> list[Any] | None:
             return channels
         if len(channels) == alternate_channel_count:
             return None
-        msg = "text_color must include exactly 3 (RGB) or 4 (CMYK) values."
+        msg = f"{color_name} must include exactly 3 (RGB) or 4 (CMYK) values."
         raise ValueError(msg)
 
     return _validator
@@ -240,6 +242,10 @@ def _serialize_text_objects(value: list[BaseModel]) -> str:
     return to_json(payload).decode()
 
 
+def _serialize_shape_objects(value: list[BaseModel]) -> list[dict[str, Any]]:
+    return [entry.model_dump(mode="json", exclude_none=True) for entry in value]
+
+
 def _serialize_signature_configuration(
     value: _PdfSignatureConfigurationModel,
 ) -> str:
@@ -1828,6 +1834,174 @@ class PdfAddTextPayload(BaseModel):
     ] = None
 
 
+class _PdfAddedShapeBaseModel(BaseModel):
+    """Shared validation and serialization for shapes added to PDFs."""
+
+    model_config = ConfigDict(extra="forbid")
+
+    page: Annotated[
+        Literal["all"] | Annotated[int, Field(ge=1)],
+        Field(serialization_alias="page"),
+    ]
+    opacity: Annotated[
+        float | None,
+        Field(serialization_alias="opacity", ge=0.0, le=1.0, default=None),
+    ] = None
+    stroke_color_rgb: Annotated[
+        tuple[RgbChannel, RgbChannel, RgbChannel] | None,
+        Field(
+            validation_alias="stroke_color",
+            serialization_alias="stroke_color_rgb",
+            default=None,
+        ),
+        BeforeValidator(
+            _route_color_by_channel_count(
+                color_name="stroke_color",
+                expected_channel_count=3,
+                alternate_channel_count=4,
+            )
+        ),
+        PlainSerializer(_serialize_as_comma_separated_string),
+    ] = None
+    stroke_color_cmyk: Annotated[
+        tuple[CmykChannel, CmykChannel, CmykChannel, CmykChannel] | None,
+        Field(
+            validation_alias="stroke_color",
+            serialization_alias="stroke_color_cmyk",
+            default=None,
+        ),
+        BeforeValidator(
+            _route_color_by_channel_count(
+                color_name="stroke_color",
+                expected_channel_count=4,
+                alternate_channel_count=3,
+            )
+        ),
+        PlainSerializer(_serialize_as_comma_separated_string),
+    ] = None
+    stroke_width: Annotated[
+        float | None,
+        Field(serialization_alias="stroke_width", gt=0, default=None),
+    ] = None
+    tag_actual_text: Annotated[
+        str | None,
+        Field(serialization_alias="tag_actual_text", min_length=1, default=None),
+    ] = None
+    tag_is_artifact: Annotated[
+        bool | None,
+        Field(serialization_alias="tag_is_artifact", default=None),
+    ] = None
+    tag_structure_type: Annotated[
+        PdfContentStructureType | None,
+        Field(serialization_alias="tag_structure_type", default=None),
+    ] = None
+
+
+class PdfAddedLineObjectModel(_PdfAddedShapeBaseModel):
+    """Adapt a line shape into the pdfRest JSON request contract."""
+
+    type: Literal["line"]
+    x1: Annotated[float, Field(ge=0, serialization_alias="x1")]
+    y1: Annotated[float, Field(ge=0, serialization_alias="y1")]
+    x2: Annotated[float, Field(ge=0, serialization_alias="x2")]
+    y2: Annotated[float, Field(ge=0, serialization_alias="y2")]
+
+
+class PdfAddedRectangleObjectModel(_PdfAddedShapeBaseModel):
+    """Adapt a rectangle shape into the pdfRest JSON request contract."""
+
+    type: Literal["rectangle"]
+    x: Annotated[float, Field(ge=0, serialization_alias="x")]
+    y: Annotated[float, Field(ge=0, serialization_alias="y")]
+    width: Annotated[float, Field(gt=0, serialization_alias="width")]
+    height: Annotated[float, Field(gt=0, serialization_alias="height")]
+    fill_color_rgb: Annotated[
+        tuple[RgbChannel, RgbChannel, RgbChannel] | None,
+        Field(
+            validation_alias="fill_color",
+            serialization_alias="fill_color_rgb",
+            default=None,
+        ),
+        BeforeValidator(
+            _route_color_by_channel_count(
+                color_name="fill_color",
+                expected_channel_count=3,
+                alternate_channel_count=4,
+            )
+        ),
+        PlainSerializer(_serialize_as_comma_separated_string),
+    ] = None
+    fill_color_cmyk: Annotated[
+        tuple[CmykChannel, CmykChannel, CmykChannel, CmykChannel] | None,
+        Field(
+            validation_alias="fill_color",
+            serialization_alias="fill_color_cmyk",
+            default=None,
+        ),
+        BeforeValidator(
+            _route_color_by_channel_count(
+                color_name="fill_color",
+                expected_channel_count=4,
+                alternate_channel_count=3,
+            )
+        ),
+        PlainSerializer(_serialize_as_comma_separated_string),
+    ] = None
+
+
+PdfAddedShapeObjectModel = Annotated[
+    PdfAddedLineObjectModel | PdfAddedRectangleObjectModel,
+    Field(discriminator="type"),
+]
+
+
+class PdfAddShapesPayload(BaseModel):
+    """Adapt caller shape options into a pdfRest-ready add-shapes request payload."""
+
+    files: Annotated[
+        list[PdfRestFile],
+        Field(
+            min_length=1,
+            max_length=1,
+            validation_alias=AliasChoices("file", "files"),
+            serialization_alias="id",
+        ),
+        BeforeValidator(_ensure_list),
+        AfterValidator(
+            _allowed_mime_types("application/pdf", error_msg="Must be a PDF file")
+        ),
+        PlainSerializer(_serialize_as_first_file_id),
+    ]
+    shape_objects: Annotated[
+        list[PdfAddedShapeObjectModel],
+        Field(serialization_alias="shape_objects", min_length=1),
+        BeforeValidator(_ensure_list),
+        PlainSerializer(_serialize_shape_objects),
+    ]
+    tag_enabled: Annotated[
+        bool | None,
+        Field(serialization_alias="tag_enabled", default=None),
+    ] = None
+    output: Annotated[
+        str | None,
+        Field(serialization_alias="output", min_length=1, default=None),
+        AfterValidator(_validate_output_prefix),
+    ] = None
+
+    @model_validator(mode="after")
+    def _require_tagging_for_shape_metadata(self) -> PdfAddShapesPayload:
+        has_tag_metadata = any(
+            shape.tag_actual_text is not None
+            or shape.tag_is_artifact is not None
+            or shape.tag_structure_type is not None
+            for shape in self.shape_objects
+        )
+        if has_tag_metadata and self.tag_enabled is not True:
+            msg = "tag_enabled must be true when tag options are provided."
+            raise ValueError(msg)
+        return self
+
+
 class PdfAddImagePayload(BaseModel):
     """Adapt caller options into a pdfRest-ready add-image request payload."""
 
@@ -1963,7 +2137,8 @@ class PdfTextWatermarkPayload(_BasePdfWatermarkPayload):
             default=None,
         ),
         BeforeValidator(
-            _route_text_color_by_channel_count(
+            _route_color_by_channel_count(
+                color_name="text_color",
                 expected_channel_count=3,
                 alternate_channel_count=4,
             )
@@ -1978,7 +2153,8 @@ class PdfTextWatermarkPayload(_BasePdfWatermarkPayload):
             default=None,
         ),
         BeforeValidator(
-            _route_text_color_by_channel_count(
+            _route_color_by_channel_count(
+                color_name="text_color",
                 expected_channel_count=4,
                 alternate_channel_count=3,
             )
diff --git a/src/pdfrest/types/__init__.py b/src/pdfrest/types/__init__.py
index f662b0b4..64cdb0e7 100644
--- a/src/pdfrest/types/__init__.py
+++ b/src/pdfrest/types/__init__.py
@@ -16,10 +16,15 @@
     HtmlWebLayout,
     JpegColorModel,
     OcrLanguage,
+    PdfAddLineObject,
+    PdfAddRectangleObject,
+    PdfAddShapeObject,
     PdfAddTextObject,
     PdfAType,
     PdfCMYKColor,
+    PdfColor,
     PdfColorProfile,
+    PdfContentStructureType,
     PdfConversionCompression,
     PdfConversionDownsample,
     PdfConversionLocale,
@@ -70,9 +75,14 @@
     "JpegColorModel",
     "OcrLanguage",
     "PdfAType",
+    "PdfAddLineObject",
+    "PdfAddRectangleObject",
+    "PdfAddShapeObject",
     "PdfAddTextObject",
     "PdfCMYKColor",
+    "PdfColor",
     "PdfColorProfile",
+    "PdfContentStructureType",
     "PdfConversionCompression",
     "PdfConversionDownsample",
     "PdfConversionLocale",
diff --git a/src/pdfrest/types/public.py b/src/pdfrest/types/public.py
index 5b7689ea..09c065cb 100644
--- a/src/pdfrest/types/public.py
+++ b/src/pdfrest/types/public.py
@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-from typing import TYPE_CHECKING, Any, Literal, cast, get_args
+from typing import TYPE_CHECKING, Any, Literal, TypeAlias, cast, get_args
 
 from typing_extensions import Required, TypedDict
 
@@ -29,9 +29,14 @@
     "JpegColorModel",
     "OcrLanguage",
     "PdfAType",
+    "PdfAddLineObject",
+    "PdfAddRectangleObject",
+    "PdfAddShapeObject",
     "PdfAddTextObject",
     "PdfCMYKColor",
+    "PdfColor",
     "PdfColorProfile",
+    "PdfContentStructureType",
     "PdfConversionCompression",
     "PdfConversionDownsample",
     "PdfConversionLocale",
@@ -135,7 +140,123 @@ class PdfRedactionInstruction(TypedDict):
 
 PdfCMYKColor = tuple[int, int, int, int]
 PdfRGBColor = tuple[int, int, int]
-PdfTextColor = PdfRGBColor | PdfCMYKColor
+PdfColor = PdfRGBColor | PdfCMYKColor
+PdfTextColor = PdfColor
+
+PdfContentStructureType = Literal[
+    "P",
+    "H",
+    "H1",
+    "H2",
+    "H3",
+    "H4",
+    "H5",
+    "H6",
+    "Lbl",
+    "Span",
+    "Quote",
+    "Note",
+    "Reference",
+    "BibEntry",
+    "Code",
+    "Link",
+    "Annot",
+    "Ruby",
+    "RB",
+    "RT",
+    "RP",
+    "Warichu",
+    "WT",
+    "WP",
+    "Figure",
+    "Formula",
+    "Form",
+]
+
+
+class PdfAddLineObject(TypedDict, total=False):
+    """Line shape inserted by [pdfrest.PdfRestClient.add_shapes_to_pdf][].
+
+    Attributes:
+        type: Required discriminator. Must be ``"line"``.
+        page: Required one-based page number or ``"all"``.
+        x1: Required horizontal start coordinate in PDF points. Must be at least 0.
+        y1: Required vertical start coordinate in PDF points. Must be at least 0.
+        x2: Required horizontal end coordinate in PDF points. Must be at least 0.
+        y2: Required vertical end coordinate in PDF points. Must be at least 0.
+        stroke_color: Optional RGB ``(red, green, blue)`` or CMYK
+            ``(cyan, magenta, yellow, black)`` tuple. RGB channels range from 0
+            through 255; CMYK channels range from 0 through 100.
+        stroke_width: Optional line width in PDF points. Must be greater than 0.
+        opacity: Optional opacity from 0 (transparent) through 1 (opaque).
+        tag_actual_text: Optional non-empty accessible text. Requires
+            ``tag_enabled=True`` on the client method.
+        tag_is_artifact: Optional artifact marker. Requires ``tag_enabled=True``
+            on the client method.
+        tag_structure_type: Optional PDF structure type. Requires
+            ``tag_enabled=True`` on the client method.
+    """
+
+    type: Required[Literal["line"]]
+    page: Required[Literal["all"] | int]
+    x1: Required[float]
+    y1: Required[float]
+    x2: Required[float]
+    y2: Required[float]
+    stroke_color: PdfColor
+    stroke_width: float
+    opacity: float
+    tag_actual_text: str
+    tag_is_artifact: bool
+    tag_structure_type: PdfContentStructureType
+
+
+class PdfAddRectangleObject(TypedDict, total=False):
+    """Rectangle shape inserted by [pdfrest.PdfRestClient.add_shapes_to_pdf][].
+
+    Attributes:
+        type: Required discriminator. Must be ``"rectangle"``.
+        page: Required one-based page number or ``"all"``.
+        x: Required horizontal lower-left coordinate in PDF points. Must be at
+            least 0.
+        y: Required vertical lower-left coordinate in PDF points. Must be at
+            least 0.
+        width: Required width in PDF points. Must be greater than 0.
+        height: Required height in PDF points. Must be greater than 0.
+        fill_color: Optional RGB ``(red, green, blue)`` or CMYK
+            ``(cyan, magenta, yellow, black)`` tuple. RGB channels range from 0
+            through 255; CMYK channels range from 0 through 100.
+        stroke_color: Optional RGB or CMYK tuple with the same channel ranges as
+            ``fill_color``.
+        stroke_width: Optional border width in PDF points. Must be greater than
+            0.
+        opacity: Optional opacity from 0 (transparent) through 1 (opaque).
+        tag_actual_text: Optional non-empty accessible text. Requires
+            ``tag_enabled=True`` on the client method.
+        tag_is_artifact: Optional artifact marker. Requires ``tag_enabled=True``
+            on the client method.
+        tag_structure_type: Optional PDF structure type. Requires
+            ``tag_enabled=True`` on the client method.
+    """
+
+    type: Required[Literal["rectangle"]]
+    page: Required[Literal["all"] | int]
+    x: Required[float]
+    y: Required[float]
+    width: Required[float]
+    height: Required[float]
+    fill_color: PdfColor
+    stroke_color: PdfColor
+    stroke_width: float
+    opacity: float
+    tag_actual_text: str
+    tag_is_artifact: bool
+    tag_structure_type: PdfContentStructureType
+
+
+PdfAddShapeObject: TypeAlias = PdfAddLineObject | PdfAddRectangleObject
+"""A line or rectangle object accepted by
+[pdfrest.PdfRestClient.add_shapes_to_pdf][]."""
 
 
 class PdfAddTextObject(TypedDict, total=False):
diff --git a/tests/conftest.py b/tests/conftest.py
index e4c4e7a5..1be9c0c7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -43,7 +43,13 @@ def pdfrest_api_key() -> str:
 def pdfrest_live_base_url(pdfrest_api_key: str) -> str:
     headers = {"Authorization": f"Bearer {pdfrest_api_key}"}
     timeout = httpx.Timeout(2.0)
-    for base_url in LIVE_BASE_URL_CANDIDATES:
+    configured_base_url = os.getenv("PDFREST_LIVE_BASE_URL")
+    base_url_candidates = (
+        (configured_base_url, *LIVE_BASE_URL_CANDIDATES)
+        if configured_base_url
+        else LIVE_BASE_URL_CANDIDATES
+    )
+    for base_url in base_url_candidates:
         try:
             with httpx.Client(base_url=base_url, timeout=timeout) as client:
                 response = client.get("/up", headers=headers)
diff --git a/tests/live/test_live_add_shapes_to_pdf.py b/tests/live/test_live_add_shapes_to_pdf.py
new file mode 100644
index 00000000..723f03d3
--- /dev/null
+++ b/tests/live/test_live_add_shapes_to_pdf.py
@@ -0,0 +1,163 @@
+from __future__ import annotations
+
+import pytest
+
+from pdfrest import AsyncPdfRestClient, PdfRestApiError, PdfRestClient
+from pdfrest.models import PdfRestFile
+
+from ..resources import get_test_resource_path
+
+
+@pytest.fixture(scope="module")
+def uploaded_pdf_for_shape_addition(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+) -> PdfRestFile:
+    with PdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        return client.files.create_from_paths([get_test_resource_path("report.pdf")])[0]
+
+
+def _line() -> dict[str, object]:
+    return {
+        "type": "line",
+        "page": 1,
+        "x1": 72,
+        "y1": 576,
+        "x2": 540,
+        "y2": 576,
+        "stroke_color": (26, 72, 112),
+        "stroke_width": 1.5,
+    }
+
+
+def _rectangle() -> dict[str, object]:
+    return {
+        "type": "rectangle",
+        "page": "all",
+        "x": 54,
+        "y": 540,
+        "width": 504,
+        "height": 108,
+        "fill_color": (0, 0, 0, 12),
+        "opacity": 0.75,
+    }
+
+
+def _server_line() -> dict[str, object]:
+    line = _line()
+    line["stroke_color_rgb"] = "26,72,112"
+    del line["stroke_color"]
+    return line
+
+
+def _server_rectangle() -> dict[str, object]:
+    rectangle = _rectangle()
+    rectangle["fill_color_cmyk"] = "0,0,0,12"
+    del rectangle["fill_color"]
+    return rectangle
+
+
+def test_live_add_shapes_to_pdf(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_shape_addition: PdfRestFile,
+) -> None:
+    with PdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        response = client.add_shapes_to_pdf(
+            uploaded_pdf_for_shape_addition,
+            shape_objects=[_line(), _rectangle()],
+            output="live-added-shapes",
+        )
+
+    assert response.output_files
+    output_file = response.output_file
+    assert output_file.type == "application/pdf"
+    assert output_file.name.startswith("live-added-shapes")
+    assert output_file.size > 0
+    assert response.warning is None
+    assert uploaded_pdf_for_shape_addition.id in response.input_ids
+
+
+@pytest.mark.asyncio
+async def test_live_async_add_shapes_to_pdf(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_shape_addition: PdfRestFile,
+) -> None:
+    async with AsyncPdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        response = await client.add_shapes_to_pdf(
+            uploaded_pdf_for_shape_addition,
+            shape_objects={
+                **_rectangle(),
+                "tag_actual_text": "Decorative panel",
+                "tag_structure_type": "Figure",
+            },
+            tag_enabled=True,
+        )
+
+    assert response.output_files
+    output_file = response.output_file
+    assert output_file.type == "application/pdf"
+    assert output_file.size > 0
+    assert response.warning is None
+    assert uploaded_pdf_for_shape_addition.id in response.input_ids
+
+
+def test_live_add_shapes_to_pdf_invalid_page(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_shape_addition: PdfRestFile,
+) -> None:
+    with (
+        PdfRestClient(
+            api_key=pdfrest_api_key,
+            base_url=pdfrest_live_base_url,
+        ) as client,
+        pytest.raises(PdfRestApiError, match=r"(?i)page"),
+    ):
+        client.add_shapes_to_pdf(
+            uploaded_pdf_for_shape_addition,
+            shape_objects=_line(),
+            extra_body={
+                "shape_objects": [
+                    {
+                        **_server_line(),
+                        "page": 0,
+                    }
+                ]
+            },
+        )
+
+
+@pytest.mark.asyncio
+async def test_live_async_add_shapes_to_pdf_invalid_page(
+    pdfrest_api_key: str,
+    pdfrest_live_base_url: str,
+    uploaded_pdf_for_shape_addition: PdfRestFile,
+) -> None:
+    async with AsyncPdfRestClient(
+        api_key=pdfrest_api_key,
+        base_url=pdfrest_live_base_url,
+    ) as client:
+        with pytest.raises(PdfRestApiError, match=r"(?i)page"):
+            await client.add_shapes_to_pdf(
+                uploaded_pdf_for_shape_addition,
+                shape_objects=_rectangle(),
+                extra_body={
+                    "shape_objects": [
+                        {
+                            **_server_rectangle(),
+                            "page": 0,
+                        }
+                    ]
+                },
+            )
diff --git a/tests/test_add_shapes_to_pdf.py b/tests/test_add_shapes_to_pdf.py
new file mode 100644
index 00000000..370deb99
--- /dev/null
+++ b/tests/test_add_shapes_to_pdf.py
@@ -0,0 +1,549 @@
+from __future__ import annotations
+
+import json
+import re
+
+import httpx
+import pytest
+from pydantic import ValidationError
+
+from pdfrest import AsyncPdfRestClient, PdfRestClient
+from pdfrest.models import PdfRestFileBasedResponse, PdfRestFileID
+from pdfrest.models._internal import PdfAddShapesPayload
+
+from .graphics_test_helpers import (
+    ASYNC_API_KEY,
+    VALID_API_KEY,
+    build_file_info_payload,
+    make_image_file,
+    make_pdf_file,
+)
+
+
+def make_line(**overrides: object) -> dict[str, object]:
+    line: dict[str, object] = {
+        "type": "line",
+        "page": 1,
+        "x1": 72,
+        "y1": 576,
+        "x2": 540,
+        "y2": 576,
+        "stroke_color": (26, 72, 112),
+        "stroke_width": 1.5,
+    }
+    line.update(overrides)
+    return line
+
+
+def make_rectangle(**overrides: object) -> dict[str, object]:
+    rectangle: dict[str, object] = {
+        "type": "rectangle",
+        "page": "all",
+        "x": 54,
+        "y": 540,
+        "width": 504,
+        "height": 108,
+        "fill_color": (0, 0, 0, 12),
+        "opacity": 0.75,
+    }
+    rectangle.update(overrides)
+    return rectangle
+
+
+def test_add_shapes_payload_serializes_line_and_rectangle() -> None:
+    pdf_file = make_pdf_file(PdfRestFileID.generate(1))
+
+    payload = PdfAddShapesPayload.model_validate(
+        {
+            "files": pdf_file,
+            "shape_objects": [
+                make_line(
+                    tag_actual_text="Section divider",
+                    tag_structure_type="Figure",
+                ),
+                make_rectangle(tag_is_artifact=True),
+            ],
+            "tag_enabled": True,
+            "output": "added-shapes",
+        }
+    ).model_dump(mode="json", by_alias=True, exclude_none=True, exclude_unset=True)
+
+    assert payload == {
+        "id": str(pdf_file.id),
+        "shape_objects": [
+            {
+                "type": "line",
+                "page": 1,
+                "x1": 72.0,
+                "y1": 576.0,
+                "x2": 540.0,
+                "y2": 576.0,
+                "stroke_color_rgb": "26,72,112",
+                "stroke_width": 1.5,
+                "tag_actual_text": "Section divider",
+                "tag_structure_type": "Figure",
+            },
+            {
+                "type": "rectangle",
+                "page": "all",
+                "x": 54.0,
+                "y": 540.0,
+                "width": 504.0,
+                "height": 108.0,
+                "fill_color_cmyk": "0,0,0,12",
+                "opacity": 0.75,
+                "tag_is_artifact": True,
+            },
+        ],
+        "tag_enabled": True,
+        "output": "added-shapes",
+    }
+
+
+def test_add_shapes_to_pdf_success(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+    pdf_file = make_pdf_file(PdfRestFileID.generate(1))
+    output_id = str(PdfRestFileID.generate())
+    expected_payload = PdfAddShapesPayload.model_validate(
+        {
+            "files": pdf_file,
+            "shape_objects": [make_line(), make_rectangle(tag_is_artifact=True)],
+            "tag_enabled": True,
+            "output": "with-shapes",
+        }
+    ).model_dump(mode="json", by_alias=True, exclude_none=True, exclude_unset=True)
+    seen: dict[str, int] = {"post": 0, "get": 0}
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        if request.method == "POST" and request.url.path == "/pdf-with-added-shapes":
+            seen["post"] += 1
+            assert json.loads(request.content) == expected_payload
+            return httpx.Response(
+                200, json={"inputId": [pdf_file.id], "outputId": [output_id]}
+            )
+        if request.method == "GET" and request.url.path == f"/resource/{output_id}":
+            seen["get"] += 1
+            return httpx.Response(
+                200,
+                json=build_file_info_payload(
+                    output_id, "with-shapes.pdf", "application/pdf"
+                ),
+            )
+        msg = f"Unexpected request {request.method} {request.url}"
+        raise AssertionError(msg)
+
+    with PdfRestClient(
+        api_key=VALID_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        response = client.add_shapes_to_pdf(
+            pdf_file,
+            shape_objects=[make_line(), make_rectangle(tag_is_artifact=True)],
+            tag_enabled=True,
+            output="with-shapes",
+        )
+
+    assert seen == {"post": 1, "get": 1}
+    assert isinstance(response, PdfRestFileBasedResponse)
+    assert response.output_file.name == "with-shapes.pdf"
+    assert response.output_file.type == "application/pdf"
+    assert response.input_id == pdf_file.id
+
+
+@pytest.mark.asyncio
+async def test_async_add_shapes_to_pdf_success(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+    pdf_file = make_pdf_file(PdfRestFileID.generate(1))
+    output_id = str(PdfRestFileID.generate())
+    seen: dict[str, int] = {"post": 0, "get": 0}
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        if request.method == "POST" and request.url.path == "/pdf-with-added-shapes":
+            seen["post"] += 1
+            payload = json.loads(request.content)
+            assert payload["id"] == str(pdf_file.id)
+            assert payload["shape_objects"] == [
+                {
+                    "type": "rectangle",
+                    "page": 1,
+                    "x": 10.0,
+                    "y": 20.0,
+                    "width": 30.0,
+                    "height": 40.0,
+                    "fill_color_rgb": "245,247,250",
+                    "tag_actual_text": "Decorative panel",
+                    "tag_structure_type": "Figure",
+                }
+            ]
+            assert payload["tag_enabled"] is True
+            assert payload["output"] == "async-with-shapes"
+            return httpx.Response(
+                200, json={"inputId": [pdf_file.id], "outputId": [output_id]}
+            )
+        if request.method == "GET" and request.url.path == f"/resource/{output_id}":
+            seen["get"] += 1
+            return httpx.Response(
+                200,
+                json=build_file_info_payload(
+                    output_id, "async-with-shapes.pdf", "application/pdf"
+                ),
+            )
+        msg = f"Unexpected request {request.method} {request.url}"
+        raise AssertionError(msg)
+
+    async with AsyncPdfRestClient(
+        api_key=ASYNC_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        response = await client.add_shapes_to_pdf(
+            pdf_file,
+            shape_objects=make_rectangle(
+                page=1,
+                x=10,
+                y=20,
+                width=30,
+                height=40,
+                fill_color=(245, 247, 250),
+                opacity=None,
+                tag_actual_text="Decorative panel",
+                tag_structure_type="Figure",
+            ),
+            tag_enabled=True,
+            output="async-with-shapes",
+        )
+
+    assert seen == {"post": 1, "get": 1}
+    assert response.output_file.name == "async-with-shapes.pdf"
+
+
+def test_add_shapes_to_pdf_request_customization(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+    pdf_file = make_pdf_file(PdfRestFileID.generate(1))
+    output_id = str(PdfRestFileID.generate())
+    captured_timeout: dict[str, object] = {}
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        if request.method == "POST" and request.url.path == "/pdf-with-added-shapes":
+            assert request.url.params["trace"] == "true"
+            assert request.headers["X-Debug"] == "1"
+            payload = json.loads(request.content)
+            assert payload["output"] == "overridden-shapes"
+            captured_timeout["value"] = request.extensions.get("timeout")
+            return httpx.Response(
+                200, json={"inputId": [pdf_file.id], "outputId": [output_id]}
+            )
+        if request.method == "GET" and request.url.path == f"/resource/{output_id}":
+            assert request.url.params["trace"] == "true"
+            assert request.headers["X-Debug"] == "1"
+            return httpx.Response(
+                200,
+                json=build_file_info_payload(
+                    output_id, "overridden-shapes.pdf", "application/pdf"
+                ),
+            )
+        msg = f"Unexpected request {request.method} {request.url}"
+        raise AssertionError(msg)
+
+    with PdfRestClient(
+        api_key=VALID_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        response = client.add_shapes_to_pdf(
+            pdf_file,
+            shape_objects=make_line(),
+            extra_query={"trace": "true"},
+            extra_headers={"X-Debug": "1"},
+            extra_body={"output": "overridden-shapes"},
+            timeout=0.25,
+        )
+
+    assert response.output_file.name == "overridden-shapes.pdf"
+    timeout_value = captured_timeout["value"]
+    assert timeout_value is not None
+    if isinstance(timeout_value, dict):
+        assert all(
+            component == pytest.approx(0.25) for component in timeout_value.values()
+        )
+    else:
+        assert timeout_value == pytest.approx(0.25)
+
+
+@pytest.mark.asyncio
+async def test_async_add_shapes_to_pdf_request_customization(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+    pdf_file = make_pdf_file(PdfRestFileID.generate(1))
+    output_id = str(PdfRestFileID.generate())
+    captured_timeout: dict[str, object] = {}
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        if request.method == "POST" and request.url.path == "/pdf-with-added-shapes":
+            assert request.url.params["trace"] == "true"
+            assert request.headers["X-Test"] == "async"
+            assert json.loads(request.content)["output"] == "async-custom-shapes"
+            captured_timeout["value"] = request.extensions.get("timeout")
+            return httpx.Response(
+                200, json={"inputId": [pdf_file.id], "outputId": [output_id]}
+            )
+        if request.method == "GET" and request.url.path == f"/resource/{output_id}":
+            assert request.url.params["trace"] == "true"
+            assert request.headers["X-Test"] == "async"
+            return httpx.Response(
+                200,
+                json=build_file_info_payload(
+                    output_id, "async-custom-shapes.pdf", "application/pdf"
+                ),
+            )
+        msg = f"Unexpected request {request.method} {request.url}"
+        raise AssertionError(msg)
+
+    async with AsyncPdfRestClient(
+        api_key=ASYNC_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        response = await client.add_shapes_to_pdf(
+            pdf_file,
+            shape_objects=make_line(),
+            extra_query={"trace": "true"},
+            extra_headers={"X-Test": "async"},
+            extra_body={"output": "async-custom-shapes"},
+            timeout=1.0,
+        )
+
+    assert response.output_file.name == "async-custom-shapes.pdf"
+    timeout_value = captured_timeout["value"]
+    assert timeout_value is not None
+    if isinstance(timeout_value, dict):
+        assert all(
+            component == pytest.approx(1.0) for component in timeout_value.values()
+        )
+    else:
+        assert timeout_value == pytest.approx(1.0)
+
+
+@pytest.mark.parametrize(
+    ("shape_objects", "tag_enabled", "match"),
+    [
+        pytest.param([], None, "at least 1 item", id="empty-shapes"),
+        pytest.param(
+            make_line(stroke_color=(0, 0)),
+            None,
+            re.escape("stroke_color must include exactly 3 (RGB) or 4 (CMYK) values."),
+            id="line-color-channel-count",
+        ),
+        pytest.param(
+            make_rectangle(fill_color=(0, 0)),
+            None,
+            re.escape("fill_color must include exactly 3 (RGB) or 4 (CMYK) values."),
+            id="rectangle-color-channel-count",
+        ),
+        pytest.param(
+            make_rectangle(width=0),
+            None,
+            "greater than 0",
+            id="zero-width",
+        ),
+        pytest.param(
+            make_line(tag_actual_text="Tagged line"),
+            False,
+            re.escape("tag_enabled must be true when tag options are provided."),
+            id="tagging-not-enabled",
+        ),
+    ],
+)
+def test_add_shapes_to_pdf_rejects_invalid_input(
+    monkeypatch: pytest.MonkeyPatch,
+    shape_objects: object,
+    tag_enabled: bool | None,
+    match: str,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+
+    def handler(_: httpx.Request) -> httpx.Response:
+        pytest.fail("Request should not be sent when validation fails.")
+
+    with (
+        PdfRestClient(
+            api_key=VALID_API_KEY, transport=httpx.MockTransport(handler)
+        ) as client,
+        pytest.raises(ValidationError, match=match),
+    ):
+        client.add_shapes_to_pdf(
+            make_pdf_file(PdfRestFileID.generate(1)),
+            shape_objects=shape_objects,  # type: ignore[arg-type]
+            tag_enabled=tag_enabled,
+        )
+
+
+@pytest.mark.asyncio
+async def test_async_add_shapes_to_pdf_rejects_non_pdf(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+
+    def handler(_: httpx.Request) -> httpx.Response:
+        pytest.fail("Request should not be sent when validation fails.")
+
+    async with AsyncPdfRestClient(
+        api_key=ASYNC_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        with pytest.raises(ValidationError, match="Must be a PDF file"):
+            await client.add_shapes_to_pdf(
+                make_image_file(PdfRestFileID.generate(1)),
+                shape_objects=make_line(),
+            )
+
+
+def test_add_shapes_to_pdf_rejects_non_pdf(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+
+    def handler(_: httpx.Request) -> httpx.Response:
+        pytest.fail("Request should not be sent when validation fails.")
+
+    with (
+        PdfRestClient(
+            api_key=VALID_API_KEY, transport=httpx.MockTransport(handler)
+        ) as client,
+        pytest.raises(ValidationError, match="Must be a PDF file"),
+    ):
+        client.add_shapes_to_pdf(
+            make_image_file(PdfRestFileID.generate(1)),
+            shape_objects=make_line(),
+        )
+
+
+def test_add_shapes_to_pdf_rejects_multiple_input_files(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+
+    def handler(_: httpx.Request) -> httpx.Response:
+        pytest.fail("Request should not be sent when validation fails.")
+
+    with (
+        PdfRestClient(
+            api_key=VALID_API_KEY, transport=httpx.MockTransport(handler)
+        ) as client,
+        pytest.raises(ValidationError, match="at most 1 item"),
+    ):
+        client.add_shapes_to_pdf(
+            [
+                make_pdf_file(PdfRestFileID.generate(1)),
+                make_pdf_file(PdfRestFileID.generate(2)),
+            ],
+            shape_objects=make_line(),
+        )
+
+
+@pytest.mark.asyncio
+async def test_async_add_shapes_to_pdf_rejects_multiple_input_files(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("PDFREST_API_KEY", raising=False)
+
+    def handler(_: httpx.Request) -> httpx.Response:
+        pytest.fail("Request should not be sent when validation fails.")
+
+    async with AsyncPdfRestClient(
+        api_key=ASYNC_API_KEY, transport=httpx.MockTransport(handler)
+    ) as client:
+        with pytest.raises(ValidationError, match="at most 1 item"):
+            await client.add_shapes_to_pdf(
+                [
+                    make_pdf_file(PdfRestFileID.generate(1)),
+                    make_pdf_file(PdfRestFileID.generate(2)),
+                ],
+                shape_objects=make_line(),
+            )
+
+
+@pytest.mark.parametrize(
+    ("shape", "match"),
+    [
+        pytest.param(make_line(x1=-1), "greater than or equal to 0", id="x1-below"),
+        pytest.param(make_line(y2=-1), "greater than or equal to 0", id="y2-below"),
+        pytest.param(make_line(page=0), "greater than or equal to 1", id="page-below"),
+        pytest.param(
+            make_line(opacity=-0.01), "greater than or equal to 0", id="opacity-below"
+        ),
+        pytest.param(
+            make_line(opacity=1.01), "less than or equal to 1", id="opacity-above"
+        ),
+        pytest.param(
+            make_line(stroke_width=0), "greater than 0", id="stroke-width-zero"
+        ),
+        pytest.param(
+            make_line(stroke_color=(-1, 0, 0)),
+            "greater than or equal to 0",
+            id="rgb-below",
+        ),
+        pytest.param(
+            make_line(stroke_color=(256, 0, 0)),
+            "less than or equal to 255",
+            id="rgb-above",
+        ),
+        pytest.param(make_rectangle(width=0), "greater than 0", id="width-zero"),
+        pytest.param(make_rectangle(height=0), "greater than 0", id="height-zero"),
+        pytest.param(
+            make_rectangle(fill_color=(-1, 0, 0, 0)),
+            "greater than or equal to 0",
+            id="cmyk-below",
+        ),
+        pytest.param(
+            make_rectangle(fill_color=(101, 0, 0, 0)),
+            "less than or equal to 100",
+            id="cmyk-above",
+        ),
+    ],
+)
+def test_add_shapes_payload_rejects_out_of_range_values(
+    shape: dict[str, object],
+    match: str,
+) -> None:
+    with pytest.raises(ValidationError, match=match):
+        PdfAddShapesPayload.model_validate(
+            {
+                "files": make_pdf_file(PdfRestFileID.generate(1)),
+                "shape_objects": shape,
+            }
+        )
+
+
+@pytest.mark.parametrize(
+    "shape",
+    [
+        pytest.param(
+            make_line(
+                page=1,
+                x1=0,
+                y1=0,
+                x2=0,
+                y2=0,
+                opacity=0,
+                stroke_color=(0, 255, 0),
+            ),
+            id="line-lower-bounds",
+        ),
+        pytest.param(
+            make_rectangle(
+                x=0,
+                y=0,
+                width=0.01,
+                height=0.01,
+                opacity=1,
+                fill_color=(0, 100, 0, 100),
+            ),
+            id="rectangle-upper-bounds",
+        ),
+    ],
+)
+def test_add_shapes_payload_accepts_boundary_values(shape: dict[str, object]) -> None:
+    payload = PdfAddShapesPayload.model_validate(
+        {
+            "files": make_pdf_file(PdfRestFileID.generate(1)),
+            "shape_objects": shape,
+        }
+    )
+
+    assert payload.shape_objects[0].model_dump(mode="json", exclude_none=True)
diff --git a/uv.lock b/uv.lock
index 78e59879..a48fd046 100644
--- a/uv.lock
+++ b/uv.lock
@@ -454,6 +454,7 @@ dependencies = [
     { name = "griffecli" },
     { name = "griffelib" },
 ]
+sdist = { url = "https://files.pythonhosted.org/packages/04/56/28a0accac339c164b52a92c6cfc45a903acc0c174caa5c1713803467b533/griffe-2.0.0.tar.gz", hash = "sha256:c68979cd8395422083a51ea7cf02f9c119d889646d99b7b656ee43725de1b80f", size = 293906, upload-time = "2026-03-23T21:06:53.402Z" }
 wheels = [
     { url = "https://files.pythonhosted.org/packages/8b/94/ee21d41e7eb4f823b94603b9d40f86d3c7fde80eacc2c3c71845476dddaa/griffe-2.0.0-py3-none-any.whl", hash = "sha256:5418081135a391c3e6e757a7f3f156f1a1a746cc7b4023868ff7d5e2f9a980aa", size = 5214, upload-time = "2026-02-09T19:09:44.105Z" },
 ]
@@ -466,6 +467,7 @@ dependencies = [
     { name = "colorama" },
     { name = "griffelib" },
 ]
+sdist = { url = "https://files.pythonhosted.org/packages/a4/f8/2e129fd4a86e52e58eefe664de05e7d502decf766e7316cc9e70fdec3e18/griffecli-2.0.0.tar.gz", hash = "sha256:312fa5ebb4ce6afc786356e2d0ce85b06c1c20d45abc42d74f0cda65e159f6ef", size = 56213, upload-time = "2026-03-23T21:06:54.8Z" }
 wheels = [
     { url = "https://files.pythonhosted.org/packages/e6/ed/d93f7a447bbf7a935d8868e9617cbe1cadf9ee9ee6bd275d3040fbf93d60/griffecli-2.0.0-py3-none-any.whl", hash = "sha256:9f7cd9ee9b21d55e91689358978d2385ae65c22f307a63fb3269acf3f21e643d", size = 9345, upload-time = "2026-02-09T19:09:42.554Z" },
 ]
@@ -474,6 +476,7 @@ wheels = [
 name = "griffelib"
 version = "2.0.0"
 source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/ad/06/eccbd311c9e2b3ca45dbc063b93134c57a1ccc7607c5e545264ad092c4a9/griffelib-2.0.0.tar.gz", hash = "sha256:e504d637a089f5cab9b5daf18f7645970509bf4f53eda8d79ed71cce8bd97934", size = 166312, upload-time = "2026-03-23T21:06:55.954Z" }
 wheels = [
     { url = "https://files.pythonhosted.org/packages/4d/51/c936033e16d12b627ea334aaaaf42229c37620d0f15593456ab69ab48161/griffelib-2.0.0-py3-none-any.whl", hash = "sha256:01284878c966508b6d6f1dbff9b6fa607bc062d8261c5c7253cb285b06422a7f", size = 142004, upload-time = "2026-02-09T19:09:40.561Z" },
 ]
@@ -961,7 +964,7 @@ wheels = [
 
 [[package]]
 name = "pdfrest"
-version = "1.0.4"
+version = "1.1.0"
 source = { editable = "." }
 dependencies = [
     { name = "exceptiongroup" },