diff --git a/docs/python_api/examples/history_debug.py b/docs/python_api/examples/history_debug.py
index 7307134ea..9c1f50cd8 100644
--- a/docs/python_api/examples/history_debug.py
+++ b/docs/python_api/examples/history_debug.py
@@ -106,7 +106,7 @@ def prepare_history():
 
         refl = pipe.GetShaderReflection(renderdoc.ShaderStage.Pixel)
 
-        if not refl.debugInfo.debuggable:
+        if refl is None or not refl.debugInfo.debuggable:
             print("Shader can't be debugged:")
             print(refl.debugInfo.debugStatus)
             return
diff --git a/docs/python_api/examples/history_debug.rst b/docs/python_api/examples/history_debug.rst
index 875b53103..da1e4ed61 100644
--- a/docs/python_api/examples/history_debug.rst
+++ b/docs/python_api/examples/history_debug.rst
@@ -117,7 +117,7 @@ Picking the first of these, we can then :ref:`move to that event <currentevent>`
 .. highlight:: python
 .. code:: python
 
-    if not refl.debugInfo.debuggable:
+    if refl is None or not refl.debugInfo.debuggable:
         print("Shader can't be debugged:")
         print(refl.debugInfo.debugStatus)
         return
@@ -342,4 +342,4 @@ This example can be found under the name "Pixel History & Shader Debug" in the p
 
     :download:`Download the example script <history_debug.py>`.
 
-.. literalinclude:: history_debug.py
\ No newline at end of file
+.. literalinclude:: history_debug.py
diff --git a/docs/stubgen.py b/docs/stubgen.py
index 25696a548..3817fa796 100644
--- a/docs/stubgen.py
+++ b/docs/stubgen.py
@@ -106,6 +106,8 @@ def process_annotation(context: Any, deps: Optional[List[str]], annot: str) -> s
             return f"'{ret}'"
         return ret
 
+    callable = annot.startswith("Callable") or annot.startswith("typing.Callable")
+
     # use non-eval path if possible, only available on python 3.14 though :(
     # we make a locals set from the module, and add top-level imported modules
     # so that e.g. datetime.datetime can be found
@@ -129,7 +131,12 @@ def process_annotation(context: Any, deps: Optional[List[str]], annot: str) -> s
         # if the import failed, we have to use eval()
         except ImportError:
             try:
-                dep_type = eval(annot, globals(), locals)
+                eval_annot = annot
+                if callable:
+                    eval_annot = eval_annot.replace("NoneType", "None")
+                    # TypeVars will get printed as ~Type
+                    eval_annot = eval_annot.replace("~", "")
+                dep_type = eval(eval_annot, globals(), locals)
                 break
             except NameError as n:
                 name = re.findall(r"'([^']*)'", str(n))[0]
@@ -146,8 +153,20 @@ def process_annotation(context: Any, deps: Optional[List[str]], annot: str) -> s
         raise ValueError("Expected typing type in complex dependency")
 
     # add a dependency on the typing object itself
+    optional = union = False
+    # detect Optional[] / Union[]
+    if hasattr(dep_type, "__origin__") and dep_type.__origin__ is typing.Union:
+        # Union with just [x, None] is Optional
+        if type(None) in dep_type.__args__ and len(dep_type.__args__) == 2:
+            optional = True
+        else:
+            union = True
     if deps is not None:
-        if "_name" in dir(dep_type):
+        if optional:
+            deps.append(f"typing.Optional")
+        elif union:
+            deps.append(f"typing.Union")
+        elif "_name" in dir(dep_type):
             deps.append(f"typing.{dep_type._name}")
         else:
             deps.append(f"typing.{dep_type.__name__}")
@@ -160,7 +179,8 @@ def process_annotation(context: Any, deps: Optional[List[str]], annot: str) -> s
             inner.append("...")
             continue
         if a is None or a is type(None):
-            inner.append("None")
+            if not optional:
+                inner.append("None")
             continue
         if a == Any:
             inner.append("Any")
@@ -193,17 +213,23 @@ def process_annotation(context: Any, deps: Optional[List[str]], annot: str) -> s
             process_annotation(context, deps, f"{module}.{a.__name__}")
 
     # Callables must format their arguments and return type (the last argument)
-    if "Callable" in annot:
+    if callable:
         ret = inner[-1]
         del inner[-1]
         inner = ", ".join(inner)
         if "_name" in dir(dep_type):
+            assert dep_type._name is not None
             return f"{dep_type._name}[[{inner}], {ret}]"
         else:
             return f"{dep_type.__name__}[[{inner}], {ret}]"
 
     inner = ", ".join(inner)
-    if "_name" in dir(dep_type):
+    if optional:
+        return f"Optional[{inner}]"
+    elif union:
+        return f"Union[{inner}]"
+    elif "_name" in dir(dep_type):
+        assert dep_type._name is not None
         return f"{dep_type._name}[{inner}]"
     else:
         return f"{dep_type.__name__}[{inner}]"
diff --git a/docs/verify-docstrings.py b/docs/verify-docstrings.py
index 5198a0fc6..98a3d399e 100644
--- a/docs/verify-docstrings.py
+++ b/docs/verify-docstrings.py
@@ -117,6 +117,11 @@ def make_c_typeval(ret: str, pattern: bool, typelist: List[str]):
     elif ret[0:5] == 'List[':
         inner = make_c_typeval(ret[5:-1], pattern, typelist)
         ret = '(const )?rdcarray<{}> ?[&*]?'.format(inner) if pattern else 'rdcarray<{}>'.format(inner)
+    elif ret[0:9] == 'Optional[':
+        inner = make_c_typeval(ret[9:-1], pattern, typelist)
+        if 'std::function' in inner or (inner.startswith("RENDERDOC_") and inner.endswith("Callback")):
+            return inner
+        ret = '(const )?{} ?\\*?'.format(inner) if pattern else '{} *'.format(inner)
     elif ret[0:6] == 'Tuple[':
         inners = [make_c_typeval(i.strip(), pattern, typelist) for i in ret[6:-1].split(',')]
         if pattern:
diff --git a/qrenderdoc/Code/Interface/Extensions.h b/qrenderdoc/Code/Interface/Extensions.h
index 20879fe2b..5d07ba407 100644
--- a/qrenderdoc/Code/Interface/Extensions.h
+++ b/qrenderdoc/Code/Interface/Extensions.h
@@ -448,7 +448,7 @@ is a layout type widget, to allow customising how children are added. By default
 added in a vertical layout.
 
 :param str windowTitle: The title of any window with this widget as its root.
-:param Callable[[CaptureContext, QWidget, str], None] closed=None: **Optional parameter**. A callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] closed=None: **Optional parameter**. A callback
   that will be called when the widget is closed by the user.
   This implicitly deletes the widget and all its children, which will no longer be valid even if a
   handle to them exists.
@@ -792,7 +792,7 @@ The widget needs to be added to a parent to become part of a panel or window.
 
   DOCUMENT(R"(Create a normal button widget.
 
-:param Callable[[CaptureContext, QWidget, str], None] pressed=None: **Optional parameter**. Callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] pressed=None: **Optional parameter**. Callback
   to be called when the button is pressed.
   Callback function signature must match :func:`WidgetCallback`.
 :return: The handle to the newly created widget.
@@ -867,8 +867,8 @@ When a capture is closed and all outputs are destroyed, the widget will automati
 output so there is no need to do that manually.
 
 :param QWidget widget: The widget to set the output for.
-:param renderdoc.ReplayOutput output: The new output to set, or ``None`` to unset any previous
-  output.
+:param Optional[renderdoc.ReplayOutput] output: The new output to set, or ``None`` to unset any
+  previous output.
 )");
   virtual void SetWidgetReplayOutput(QWidget *widget, IReplayOutput *output) = 0;
 
@@ -890,7 +890,7 @@ checkerboard to be rendered instead. This is the default behaviour when a widget
   DOCUMENT(R"(Create a checkbox widget which can be toggled between unchecked and checked. When
 created the checkbox is unchecked.
 
-:param Callable[[CaptureContext, QWidget, str], None] changed=None: **Optional parameter**. Callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] changed=None: **Optional parameter**. Callback
   to be called when the widget is toggled.
   Callback function signature must match :func:`WidgetCallback`.
 :return: The handle to the newly created widget.
@@ -904,7 +904,7 @@ at most one radio box in any group of sibling radio boxes being checked.
 Upon creation the radio box is unchecked, even in a group of other radio boxes that are unchecked.
 If you want a default radio box to be checked, you should use :meth:`SetWidgetChecked`.
 
-:param Callable[[CaptureContext, QWidget, str], None] changed=None: **Optional parameter**. Callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] changed=None: **Optional parameter**. Callback
   to be called when the widget is toggled.
   Callback function signature must match :func:`WidgetCallback`.
 :return: The handle to the newly created widget.
@@ -976,7 +976,7 @@ happen.
 
 :param bool singleLine: ``True`` if the widget should be a single-line entry, otherwise it is a
   multi-line text box.
-:param Callable[[CaptureContext, QWidget, str], None] changed=None: **Optional parameter**. Callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] changed=None: **Optional parameter**. Callback
   to be called when the text in the textbox is changed.
   Callback function signature must match :func:`WidgetCallback`.
 :return: The handle to the newly created widget.
@@ -991,7 +991,7 @@ When created there are no pre-defined entries in the drop-down section. This can
 
 :param bool editable: ``True`` if the widget should allow the user to enter any text they wish as
   well as being able to select a pre-defined entry.
-:param Callable[[CaptureContext, QWidget, str], None] changed=None: **Optional parameter**. Callback
+:param Optional[Callable[[CaptureContext, QWidget, str], None]] changed=None: **Optional parameter**. Callback
   to be called when the text in the combobox is changed. This
   will be called both when a new option is selected or when the user edits the text.
   Callback function signature must match :func:`WidgetCallback`.
diff --git a/qrenderdoc/Code/Interface/QRDInterface.h b/qrenderdoc/Code/Interface/QRDInterface.h
index 03d6017b8..ab09e87ce 100644
--- a/qrenderdoc/Code/Interface/QRDInterface.h
+++ b/qrenderdoc/Code/Interface/QRDInterface.h
@@ -405,7 +405,7 @@ If no capture is loaded or the EID doesn't correspond to a known event, ``None``
 
 :param int eventId: The EID to look up.
 :return: The action containing the EID, or ``None`` if no such EID exists.
-:rtype: renderdoc.ActionDescription
+:rtype: Optional[renderdoc.ActionDescription]
 )");
   virtual const ActionDescription *GetActionForEID(uint32_t eventId) = 0;
 
@@ -416,7 +416,7 @@ If no capture is loaded or the EID doesn't correspond to a known event, an empty
 returned.
 
 :param int eventId: The EID to look up.
-:return: The formatted name of the specified event, or ``None`` if no such EID exists.
+:return: The formatted name of the specified event, or an empty string if no such EID exists.
 :rtype: str
 )");
   virtual rdcstr GetEventName(uint32_t eventId) = 0;
@@ -450,11 +450,11 @@ expression.
 :param Callable[[CaptureContext,str,str,int,renderdoc.SDChunk,renderdoc.ActionDescription,str], bool] filter: The
   callback to call for each candidate event to perform filtering.
   Callback function signature must match :func:`EventFilterCallback`.
-:param Callable[[CaptureContext,str,str], str] parser=None: **Optional parameter**. The callback to
+:param Optional[Callable[[CaptureContext,str,str], str]] parser=None: **Optional parameter**. The callback to
   call when the parsing the parameters and checking for any errors. This can be ``None`` if no
   pre-parsing is required.
   Callback function signature must match :func:`FilterParseCallback`.
-:param Callable[[CaptureContext,str,str], List[str]] completer=None: **Optional parameter**. The
+:param Optional[Callable[[CaptureContext,str,str], List[str]]] completer=None: **Optional parameter**. The
   callback to call when trying to provide autocomplete suggestions. This can be ``None`` if no
   completion is desired/applicable.
   Callback function signature must match :func:`AutoCompleteCallback`.
@@ -1256,7 +1256,7 @@ If the PID is unrecognised, no connection will be made.
 
 :param int pid: The PID of the child to connect to.
 :return: The connection window if successful, or ``None`` if no connection was made.
-:rtype: CaptureConnection
+:rtype: Optional[CaptureConnection]
 )");
   virtual ICaptureConnection *ConnectToChild(uint32_t pid) = 0;
 
@@ -1334,7 +1334,7 @@ QWidget.
   DOCUMENT(R"(Launches a capture of the current executable.
 
 :return: The connection window if successful, or ``None`` if no connection was made.
-:rtype: CaptureConnection
+:rtype: Optional[CaptureConnection]
 )");
   virtual ICaptureConnection *Launch() = 0;
 
@@ -1958,7 +1958,7 @@ struct IReplayManager
   DOCUMENT(R"(Retrieves the capture access handle for the currently open file.
 
 :return: The file handle active, or ``None`` if no capture is open.
-:rtype: renderdoc.CaptureAccess
+:rtype: Optional[renderdoc.CaptureAccess]
 )");
   virtual ICaptureAccess *GetCaptureAccess() = 0;
 
@@ -1969,7 +1969,7 @@ will be usable.
 
 :return: The file handle active, or ``None`` if no capture is open or the capture is only available
   remotely.
-:rtype: renderdoc.CaptureFile
+:rtype: Optional[renderdoc.CaptureFile]
 )");
   virtual ICaptureFile *GetCaptureFile() = 0;
 
@@ -2374,7 +2374,7 @@ recommended that you do not cache this object and use it only in local areas of
   non-blocking.
 
 :return: A blocking version of the :class:`renderdoc.ReplayController`.
-:rtype: renderdoc.ReplayController
+:rtype: Optional[renderdoc.ReplayController]
 )");
   //////////////////////////////////////////////////////////////
   // This function is implemented only for python! it will return NULL unconditionally
@@ -2613,21 +2613,21 @@ more information for how this differs.
   DOCUMENT(R"(Retrieve the current action.
 
 :return: The current action, or ``None`` if no action is selected.
-:rtype: renderdoc.ActionDescription
+:rtype: Optional[renderdoc.ActionDescription]
 )");
   virtual const ActionDescription *CurAction() = 0;
 
   DOCUMENT(R"(Retrieve the first action in the capture.
 
 :return: The first action.
-:rtype: renderdoc.ActionDescription
+:rtype: Optional[renderdoc.ActionDescription]
 )");
   virtual const ActionDescription *GetFirstAction() = 0;
 
   DOCUMENT(R"(Retrieve the last action in the capture.
 
 :return: The last action.
-:rtype: renderdoc.ActionDescription
+:rtype: Optional[renderdoc.ActionDescription]
 )");
   virtual const ActionDescription *GetLastAction() = 0;
 
@@ -2642,7 +2642,7 @@ more information for how this differs.
 
 :param renderdoc.ResourceId id: The ID of the resource to query about.
 :return: The information about a resource, or ``None`` if the ID does not correspond to a resource.
-:rtype: renderdoc.ResourceDescription
+:rtype: Optional[renderdoc.ResourceDescription]
 )");
   virtual const ResourceDescription *GetResource(ResourceId id) const = 0;
 
@@ -2732,7 +2732,7 @@ considered out of date
 
 :param renderdoc.ResourceId id: The ID of the texture to query about.
 :return: The information about a texture, or ``None`` if the ID does not correspond to a texture.
-:rtype: renderdoc.TextureDescription
+:rtype: Optional[renderdoc.TextureDescription]
 )");
   virtual TextureDescription *GetTexture(ResourceId id) = 0;
 
@@ -2747,7 +2747,7 @@ considered out of date
 
 :param renderdoc.ResourceId id: The ID of the buffer to query about.
 :return: The information about a buffer, or ``None`` if the ID does not correspond to a buffer.
-:rtype: renderdoc.BufferDescription
+:rtype: Optional[renderdoc.BufferDescription]
 )");
   virtual BufferDescription *GetBuffer(ResourceId id) = 0;
 
@@ -2763,7 +2763,7 @@ considered out of date
 :param renderdoc.ResourceId id: The ID of the buffer to query about.
 :return: The information about a descriptor store, or ``None`` if the ID does not correspond to a
   descriptor store.
-:rtype: renderdoc.DescriptorStoreDescription
+:rtype: Optional[renderdoc.DescriptorStoreDescription]
 )");
   virtual DescriptorStoreDescription *GetDescriptorStore(ResourceId id) = 0;
 
@@ -2773,7 +2773,7 @@ considered out of date
 :param int eventId: The :data:`eventId <renderdoc.APIEvent.eventId>` to query for.
 :return: The information about the action, or ``None`` if the
   :data:`eventId <renderdoc.APIEvent.eventId>` doesn't correspond to an action.
-:rtype: renderdoc.ActionDescription
+:rtype: Optional[renderdoc.ActionDescription]
 )");
   virtual const ActionDescription *GetAction(uint32_t eventId) = 0;
 
@@ -2809,7 +2809,7 @@ The handle returned is invalidated when the capture is closed, or if :meth:`Open
 called.
 
 :return: The RGP interop connection handle.
-:rtype: RGPInterop
+:rtype: Optional[RGPInterop]
 )");
   virtual IRGPInterop *GetRGPInterop() = 0;
 
@@ -3413,7 +3413,7 @@ The return value will be ``None`` if the capture is not using the D3D11 API.
 You should determine the API of the capture first before fetching it.
 
 :return: The current D3D11 pipeline state.
-:rtype: renderdoc.D3D11State
+:rtype: Optional[renderdoc.D3D11State]
 )");
   virtual const D3D11Pipe::State *CurD3D11PipelineState() = 0;
 
@@ -3423,7 +3423,7 @@ The return value will be ``None`` if the capture is not using the D3D12 API.
 You should determine the API of the capture first before fetching it.
 
 :return: The current D3D12 pipeline state.
-:rtype: renderdoc.D3D12State
+:rtype: Optional[renderdoc.D3D12State]
 )");
   virtual const D3D12Pipe::State *CurD3D12PipelineState() = 0;
 
@@ -3433,7 +3433,7 @@ The return value will be ``None`` if the capture is not using the OpenGL API.
 You should determine the API of the capture first before fetching it.
 
 :return: The current OpenGL pipeline state.
-:rtype: renderdoc.GLState
+:rtype: Optional[renderdoc.GLState]
 )");
   virtual const GLPipe::State *CurGLPipelineState() = 0;
 
@@ -3443,7 +3443,7 @@ The return value will be ``None`` if the capture is not using the Vulkan API.
 You should determine the API of the capture first before fetching it.
 
 :return: The current Vulkan pipeline state.
-:rtype: renderdoc.VKState
+:rtype: Optional[renderdoc.VKState]
 )");
   virtual const VKPipe::State *CurVulkanPipelineState() = 0;
 
diff --git a/qrenderdoc/Code/Interface/RemoteHost.h b/qrenderdoc/Code/Interface/RemoteHost.h
index 81b38b742..40ca3d78d 100644
--- a/qrenderdoc/Code/Interface/RemoteHost.h
+++ b/qrenderdoc/Code/Interface/RemoteHost.h
@@ -150,7 +150,7 @@ public:
   DOCUMENT(R"(
 :return: The :class:`~renderdoc.DeviceProtocolController` for this host, or ``None`` if no protocol
   is in use
-:rtype: renderdoc.DeviceProtocolController
+:rtype: Optional[renderdoc.DeviceProtocolController]
 )");
   IDeviceProtocolController *Protocol() const { return m_protocol; }
   DOCUMENT(R"(
diff --git a/renderdoc/api/replay/data_types.h b/renderdoc/api/replay/data_types.h
index 619b6a8a3..d987cc0eb 100644
--- a/renderdoc/api/replay/data_types.h
+++ b/renderdoc/api/replay/data_types.h
@@ -893,7 +893,7 @@ typically it is one parent to many derived.
   DOCUMENT(R"(An optional set of annotations associated with this resource, may be ``None`` if
 annotations are not used.
 
-:type: SDObject
+:type: Optional[SDObject]
 )");
   SDObject *annotations = NULL;
 
@@ -1253,7 +1253,7 @@ markers added to the capture after load.
   DOCUMENT(R"(An optional set of annotations associated with this event, may be ``None`` if
 annotations are not used.
 
-:type: SDObject
+:type: Optional[SDObject]
 )");
   SDObject *annotations = NULL;
 
@@ -2526,19 +2526,19 @@ operation.
 
   DOCUMENT(R"(The parent of this action, or ``None`` if there is no parent for this action.
 
-:type: ActionDescription
+:type: Optional[ActionDescription]
 )");
   const ActionDescription *parent = NULL;
 
   DOCUMENT(R"(The previous action in the frame, or ``None`` if this is the first action in the
 frame.
 
-:type: ActionDescription
+:type: Optional[ActionDescription]
 )");
   const ActionDescription *previousAction = NULL;
   DOCUMENT(R"(The next action in the frame, or ``None`` if this is the last action in the frame.
 
-:type: ActionDescription
+:type: Optional[ActionDescription]
 )");
   const ActionDescription *nextAction = NULL;
 
diff --git a/renderdoc/api/replay/pipestate.h b/renderdoc/api/replay/pipestate.h
index c52fbdebf..9f9fd1d2a 100644
--- a/renderdoc/api/replay/pipestate.h
+++ b/renderdoc/api/replay/pipestate.h
@@ -258,7 +258,7 @@ This returns ``None`` if no shader is bound.
 
 :param ShaderStage stage: The shader stage to fetch.
 :return: The reflection data for the given shader.
-:rtype: ShaderReflection
+:rtype: Optional[ShaderReflection]
 )");
   const ShaderReflection *GetShaderReflection(ShaderStage stage) const;
 
diff --git a/renderdoc/api/replay/renderdoc_replay.h b/renderdoc/api/replay/renderdoc_replay.h
index 77a888406..333bb52fd 100644
--- a/renderdoc/api/replay/renderdoc_replay.h
+++ b/renderdoc/api/replay/renderdoc_replay.h
@@ -445,7 +445,7 @@ struct IReplayController
 :param WindowingData window: A :class:`WindowingData` describing the native window.
 :param ReplayOutputType type: What type of output to create
 :return: A handle to the created output, or ``None`` on failure
-:rtype: ReplayOutput
+:rtype: Optional[ReplayOutput]
 )");
   virtual IReplayOutput *CreateOutput(WindowingData window, ReplayOutputType type) = 0;
 
@@ -494,7 +494,7 @@ You should use :meth:`GetAPIProperties` to determine the API of the capture.
 See also :meth:`GetPipelineState`.
 
 :return: The current D3D11 pipeline state.
-:rtype: D3D11State
+:rtype: Optional[D3D11State]
 )");
   virtual const D3D11Pipe::State *GetD3D11PipelineState() = 0;
 
@@ -506,7 +506,7 @@ You should use :meth:`GetAPIProperties` to determine the API of the capture.
 See also :meth:`GetPipelineState`.
 
 :return: The current D3D12 pipeline state.
-:rtype: D3D12State
+:rtype: Optional[D3D12State]
 )");
   virtual const D3D12Pipe::State *GetD3D12PipelineState() = 0;
 
@@ -518,7 +518,7 @@ You should use :meth:`GetAPIProperties` to determine the API of the capture.
 See also :meth:`GetPipelineState`.
 
 :return: The current OpenGL pipeline state.
-:rtype: GLState
+:rtype: Optional[GLState]
 )");
   virtual const GLPipe::State *GetGLPipelineState() = 0;
 
@@ -530,7 +530,7 @@ You should use :meth:`GetAPIProperties` to determine the API of the capture.
 See also :meth:`GetPipelineState`.
 
 :return: The current Vulkan pipeline state.
-:rtype: VKState
+:rtype: Optional[VKState]
 )");
   virtual const VKPipe::State *GetVulkanPipelineState() = 0;
 
@@ -1223,7 +1223,7 @@ The details of the types of messages that can be received are listed under
   This function will block but only to a limited degree. If no message is waiting after a small time
   it will return with a No-op message to allow further processing.
 
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value when a long blocking message is coming through,
   e.g. a capture copy. Can be ``None`` if no progress is desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1325,7 +1325,7 @@ separate thread.
   If this is ``False``, the function will not interact or block forever on user interaction and will
   always assume the input is effectively 'cancel' or empty. This may cause the symbol resolution to
   fail.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the resolver process. Can be ``None`` if no
   progress is desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1515,7 +1515,7 @@ This is primarily useful for when a capture is only stored locally and must be r
 the capture must be available on the machine where the replay happens.
 
 :param str filename: The path to the file on the local system.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the copy. Can be ``None`` if no progress is
   desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1531,7 +1531,7 @@ This function will block until the copy is fully complete, or an error has occur
 
 :param str remotepath: The remote path where the file should be copied from.
 :param str localpath: The local path where the file should be saved.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the copy. Can be ``None`` if no progress is
   desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1555,7 +1555,7 @@ or an error has occurred.
 :param str filename: The path on the remote system where the file is. If the file is only available
   locally you can use :meth:`CopyCaptureToRemote` to transfer it over the remote connection.
 :param ReplayOptions opts: The options controlling how the capture should be replayed.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the opening. Can be ``None`` if no progress is
   desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1599,7 +1599,7 @@ empty or unrecognised.
 
 :param str filename: The filename of the file to open.
 :param str filetype: The format of the given file.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value if an import step occurs. Can be ``None`` if no
   progress is desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1617,7 +1617,7 @@ For the :paramref:`OpenBuffer.filetype` parameter, see :meth:`OpenFile`.
 
 :param bytes buffer: The buffer containing the data to process.
 :param str filetype: The format of the given file.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value if an import step occurs. Can be ``None`` if no
   progress is desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1648,12 +1648,12 @@ representation back to native RDC.
 
 :param str filename: The filename to save to.
 :param str filetype: The format to convert to.
-:param SDFile file=None: **Optional parameter**. An optional :class:`SDFile` with the structured
+:param Optional[SDFile] file=None: **Optional parameter**. An optional :class:`SDFile` with the structured
   data to source from. This is useful in case the format specifies that it doesn't need buffers, and
   you already have a :class:`ReplayController` open with the structured data. This saves the need to
   load the file again. If ``None`` then structured data will be fetched if not already present and
   used.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the conversion. Can be ``None`` if no progress
   is desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1743,7 +1743,7 @@ Once the replay is created, this :class:`CaptureFile` can be shut down, there is
 by the :class:`ReplayController`.
 
 :param ReplayOptions opts: The options controlling how the capture should be replayed.
-:param Callable[[float], None] progress=None: **Optional parameter**. A callback that will be
+:param Optional[Callable[[float], None]] progress=None: **Optional parameter**. A callback that will be
   repeatedly called with an updated progress value for the opening. Can be ``None`` if no progress is
   desired.
   Callback function signature must match :func:`ProgressCallback`.
@@ -1974,7 +1974,7 @@ This function will block until the control connection is ready, or an error occu
 :param bool forceConnection: Force the connection and kick off any existing client that is currently
   connected.
 :return: A handle to the target control connection, or ``None`` if something went wrong.
-:rtype: TargetControl
+:rtype: Optional[TargetControl]
 )");
 extern "C" RENDERDOC_API ITargetControl *RENDERDOC_CC RENDERDOC_CreateTargetControl(
     const rdcstr &URL, uint32_t ident, const rdcstr &clientName, bool forceConnection);
@@ -2033,11 +2033,12 @@ This function will block until a remote connection tells the server to shut down
 
 :param str listenhost: The name of the interface to listen on.
 :param int port: The port to listen on, or ``0`` to listen on the default port.
-:param Callable[[], bool] killReplay: A callback that returns a ``bool`` indicating if the server should
-  be shut down or not.
+:param Optional[Callable[[], bool]] killReplay=None: **Optional parameter**.
+  A callback that returns a ``bool`` indicating if the server should be shut down or not.
   Callback function signature must match :func:`KillCallback`.
-:param Callable[[bool], WindowingData] previewWindow: A callback that returns information for a preview window
-  when the server wants to display some preview of the ongoing replay.
+:param Optional[Callable[[bool], WindowingData]] previewWindow=None: **Optional parameter**.
+  A callback that returns information for a preview window when the server wants to display
+  some preview of the ongoing replay.
   Callback function signature must match :func:`PreviewWindowCallback`.
 )");
 extern "C" RENDERDOC_API void RENDERDOC_CC RENDERDOC_BecomeRemoteServer(
@@ -2180,11 +2181,18 @@ struct VulkanLayerRegistrationInfo
   rdcarray<rdcstr> otherJSONs;
 };
 
-DOCUMENT("INTERNAL: Determine vulkan layer registration status.");
+DOCUMENT(R"(INTERNAL: Determine vulkan layer registration status.
+
+:param VulkanLayerRegistrationInfo x: Internal parameter
+:rtype bool
+)");
 extern "C" RENDERDOC_API bool RENDERDOC_CC
 RENDERDOC_NeedVulkanLayerRegistration(VulkanLayerRegistrationInfo *info);
 
-DOCUMENT("INTERNAL: Update vulkan layer registration.");
+DOCUMENT(R"(INTERNAL: Update vulkan layer registration.
+
+:param bool x: Internal parameter
+)");
 extern "C" RENDERDOC_API void RENDERDOC_CC RENDERDOC_UpdateVulkanLayerRegistration(bool systemLevel);
 
 //////////////////////////////////////////////////////////////////////////
@@ -2439,7 +2447,7 @@ immediate use of it may block.
 :param str protocol: The protocol to fetch a controller for.
 :return: A handle to the protocol controller, or ``None`` if something went wrong such as an
   unsupported protocol being specified.
-:rtype: DeviceProtocolController
+:rtype: Optional[DeviceProtocolController]
 )");
 extern "C" RENDERDOC_API IDeviceProtocolController *RENDERDOC_CC
 RENDERDOC_GetDeviceProtocolController(const rdcstr &protocol);
diff --git a/renderdoc/api/replay/shader_types.h b/renderdoc/api/replay/shader_types.h
index b050934f2..bcac54ebf 100644
--- a/renderdoc/api/replay/shader_types.h
+++ b/renderdoc/api/replay/shader_types.h
@@ -1120,7 +1120,7 @@ shader and generate new debug states.
 
 If this is ``None`` then the trace is invalid.
 
-:type: ShaderDebugger
+:type: Optional[ShaderDebugger]
 )");
   ShaderDebugger *debugger = NULL;
 
diff --git a/renderdoc/api/replay/structured_data.h b/renderdoc/api/replay/structured_data.h
index c1d0f641f..5c30f4ad7 100644
--- a/renderdoc/api/replay/structured_data.h
+++ b/renderdoc/api/replay/structured_data.h
@@ -707,7 +707,7 @@ returned.
 
 :param str childName: The name to search for.
 :return: A reference to the child object if found, or ``None`` if not.
-:rtype: SDObject
+:rtype: Optional[SDObject]
 )");
   inline SDObject *FindChild(const rdcstr &childName)
   {
@@ -724,7 +724,7 @@ The order of the search is not guaranteed, so care should be taken when the name
 
 :param str childName: The name to search for.
 :return: A reference to the child object if found, or ``None`` if not.
-:rtype: SDObject
+:rtype: Optional[SDObject]
 )");
   inline SDObject *FindChildRecursively(const rdcstr &childName)
   {
@@ -801,7 +801,7 @@ manipulated by key path exclusively or not at all.
 
 :param str keyPath: The key path to search for and return.
 :return: Whether or not a child exists at the given key path
-:rtype: SDObject
+:rtype: Optional[SDObject]
 )");
   inline const SDObject *FindChildByKeyPath(const rdcstr &keyPath) const
   {
@@ -868,7 +868,7 @@ returned.
 
 :param int index: The index to look up.
 :return: A reference to the child object if valid, or ``None`` if not.
-:rtype: SDObject
+:rtype: Optional[SDObject]
 )");
   inline SDObject *GetChild(size_t index)
   {
@@ -884,7 +884,7 @@ returned.
   DOCUMENT(R"(Get the parent of this object. If this object has no parent, ``None`` is returned.
 
 :return: A reference to the parent object if valid, or ``None`` if not.
-:rtype: SDObject
+:rtype: Optional[SDObject]
 )");
   inline SDObject *GetParent() { return m_Parent; }
 #if !defined(SWIG)