diff --git a/lib/ash_oaskit/core/type_mapper.ex b/lib/ash_oaskit/core/type_mapper.ex
index d92283d..223f2b2 100644
--- a/lib/ash_oaskit/core/type_mapper.ex
+++ b/lib/ash_oaskit/core/type_mapper.ex
@@ -55,6 +55,7 @@ defmodule AshOaskit.TypeMapper do
   | `Ash.Type.File` | `string` (`byte`) | Base64 encoded content |
   | `Ash.Type.DurationName` | `string` | Enum from the type's `values/0` |
   | `Ash.Type.Enum` implementors | `string` | Enum from the type's `values/0` |
+  | `Ash.TypedStruct` modules | `object` | Typed properties and required list from the field definitions |
   | `Ash.Type.NewType` wrappers | (subtype schema) | Resolved via `subtype_of/0` |
   | Custom types | Calls `json_schema/1` | If defined on type |
 
@@ -241,6 +242,7 @@ defmodule AshOaskit.TypeMapper do
 
   defp complex_type_schema({:union, types}), do: build_union_schema(types)
   defp complex_type_schema({:struct, module}), do: build_struct_schema(module)
+  defp complex_type_schema({:struct_fields, module}), do: build_typed_struct_schema(module)
   defp complex_type_schema({:custom, custom_schema}), do: custom_schema
   defp complex_type_schema(_), do: %{"type" => "string"}
 
@@ -285,6 +287,37 @@ defmodule AshOaskit.TypeMapper do
 
   defp build_struct_schema(_), do: %{"type" => "object"}
 
+  # Build an object schema for a NewType of Ash.Type.Struct (e.g. a
+  # module defined with `use Ash.TypedStruct`). Unlike build_struct_schema/1,
+  # the field definitions carry declared types and allow_nil? flags in the
+  # NewType's subtype constraints, so properties keep their real types and
+  # non-nil fields become required.
+  defp build_typed_struct_schema(module) do
+    fields = module.subtype_constraints()[:fields] || []
+
+    properties =
+      Map.new(fields, fn {name, config} ->
+        {to_string(name), ash_type_to_base_schema(Keyword.get(config, :type, :string))}
+      end)
+
+    required =
+      for {name, config} <- fields,
+          Keyword.get(config, :allow_nil?, true) == false,
+          do: to_string(name)
+
+    schema = %{
+      "type" => "object",
+      "properties" => properties,
+      "description" => "Struct of type #{inspect(module)}"
+    }
+
+    if required == [] do
+      schema
+    else
+      Map.put(schema, "required", Enum.sort(required))
+    end
+  end
+
   # Known basic atom types
   @basic_types ~w(string ci_string integer float decimal boolean date time time_usec
                   datetime utc_datetime utc_datetime_usec naive_datetime duration uuid
@@ -356,12 +389,13 @@ defmodule AshOaskit.TypeMapper do
   # Ash.Type.Enum implementors, and NewType wrappers
   defp normalize_complex_type(type) do
     cond do
-      embedded_resource?(type) ->
-        {:embedded, type}
-
+      # make sure callback always take priority
       has_json_schema_callback?(type) ->
         {:custom, get_custom_json_schema(type)}
 
+      embedded_resource?(type) ->
+        {:embedded, type}
+
       union_result = get_union_types(type) ->
         union_result
 
@@ -369,13 +403,24 @@ defmodule AshOaskit.TypeMapper do
         {:custom, enum_schema(type)}
 
       newtype?(type) ->
-        type |> NewType.subtype_of() |> normalize_type()
+        normalize_newtype(type)
 
       true ->
         :string
     end
   end
 
+  # NewType wrappers resolve to their subtype — except typed structs
+  # (subtype_of: :struct, e.g. `use Ash.TypedStruct`), whose field
+  # definitions live in the NewType's constraints and would be lost by
+  # plain recursion on the subtype
+  defp normalize_newtype(type) do
+    case NewType.subtype_of(type) do
+      Ash.Type.Struct -> {:struct_fields, type}
+      subtype -> normalize_type(subtype)
+    end
+  end
+
   # Check if a type uses Ash.Type.Enum (e.g. `use Ash.Type.Enum, values: [...]`)
   defp enum_type?(type) do
     Code.ensure_loaded?(type) and Spark.implements_behaviour?(type, Ash.Type.Enum)
diff --git a/test/ash_oaskit/kitchen_sink_test.exs b/test/ash_oaskit/kitchen_sink_test.exs
index ab43c8c..09dfe4c 100644
--- a/test/ash_oaskit/kitchen_sink_test.exs
+++ b/test/ash_oaskit/kitchen_sink_test.exs
@@ -6,6 +6,7 @@ defmodule AshOaskit.KitchenSinkTest do
   covering:
 
   - Union types (Ash.Type.NewType subtype of Ash.Type.Union)
+  - Typed structs (Ash.TypedStruct), direct and as discriminated-union variants
   - Custom types with json_schema/1 callback
   - Deeply nested embedded resources (3 levels: Venue → Location → GeoPoint)
   - Array of embedded resources
@@ -87,6 +88,71 @@ defmodule AshOaskit.KitchenSinkTest do
     end
   end
 
+  describe "discriminated union of typed structs (actor)" do
+    test "3.1 documents typed variants with declared field types", %{spec_31: spec} do
+      actor = get_attr(spec, "actor")
+
+      assert %{
+               "anyOf" => [
+                 %{"type" => "null"},
+                 %{
+                   "title" => "person",
+                   "description" => "Struct of type AshOaskit.Test.Person",
+                   "properties" => %{
+                     "age" => %{"type" => "integer"},
+                     "email" => %{"type" => "string"},
+                     "name" => %{"type" => "string"},
+                     "type" => %{"type" => "string"}
+                   },
+                   "required" => ["email", "name", "type"],
+                   "type" => "object"
+                 },
+                 %{
+                   "title" => "company",
+                   "description" => "Struct of type AshOaskit.Test.Company",
+                   "properties" => %{
+                     "company_name" => %{"type" => "string"},
+                     "employee_count" => %{"type" => "integer"},
+                     "tax_id" => %{"type" => "string"},
+                     "type" => %{"type" => "string"}
+                   },
+                   "required" => ["company_name", "tax_id", "type"],
+                   "type" => "object"
+                 }
+               ],
+               "description" => "The actor (person or company) associated with this record"
+             } === actor
+    end
+
+    test "3.0 uses anyOf with nullable flag", %{spec_30: spec} do
+      actor = get_attr(spec, "actor")
+
+      assert actor["nullable"] == true
+      assert [person, _] = actor["anyOf"]
+      assert person["properties"]["age"]["type"] == "integer"
+    end
+  end
+
+  describe "typed struct as a direct attribute (owner)" do
+    test "3.1 documents a typed nullable object", %{spec_31: spec} do
+      owner = get_attr(spec, "owner")
+
+      assert owner["type"] == ["object", "null"]
+      assert owner["properties"]["age"]["type"] == "integer"
+      assert owner["properties"]["name"]["type"] == "string"
+      assert owner["required"] == ["email", "name", "type"]
+      assert owner["description"] == "The owner of this record"
+    end
+
+    test "3.0 uses the nullable flag", %{spec_30: spec} do
+      owner = get_attr(spec, "owner")
+
+      assert owner["type"] == "object"
+      assert owner["nullable"] == true
+      assert owner["properties"]["age"]["type"] == "integer"
+    end
+  end
+
   describe "deeply nested embedded resources" do
     test "venue references Venue via $ref (3.1)", %{spec_31: spec} do
       venue_attr = get_attr(spec, "venue")
@@ -242,6 +308,16 @@ defmodule AshOaskit.KitchenSinkTest do
     end
   end
 
+  describe "Oaskit validation" do
+    test "3.1 spec with typed structs passes Oaskit validation", %{spec_31: spec} do
+      assert {:ok, %Oaskit.Spec.OpenAPI{}} = AshOaskit.validate(spec)
+    end
+
+    test "3.0 spec with typed structs passes Oaskit validation", %{spec_30: spec} do
+      assert {:ok, %Oaskit.Spec.OpenAPI{}} = AshOaskit.validate(spec)
+    end
+  end
+
   # --- Helpers ---
 
   defp get_attr(spec, name) do
diff --git a/test/support/kitchen_sink_resources.ex b/test/support/kitchen_sink_resources.ex
index aeb2a3b..1af0131 100644
--- a/test/support/kitchen_sink_resources.ex
+++ b/test/support/kitchen_sink_resources.ex
@@ -6,6 +6,7 @@
 # - Deeply nested embedded resources (3+ levels)
 # - Array of embedded resources
 # - Union types as attributes (via Ash.Type.NewType)
+# - Typed structs (Ash.TypedStruct), direct and as discriminated-union variants
 # - Read-only attributes (writable?: false) — excluded from input schemas
 # - DurationName type in a real resource
 # - Custom type with json_schema/1 callback in a real resource
@@ -44,6 +45,64 @@ defmodule AshOaskit.Test.ContentBlock do
     ]
 end
 
+# ===========================================================================
+# Typed Structs and a Discriminated Union of them (regression: these
+# previously degraded to "string" schemas)
+# ===========================================================================
+
+defmodule AshOaskit.Test.Person do
+  @moduledoc """
+  TypedStruct for Person variant.
+  """
+
+  use Ash.TypedStruct
+
+  typed_struct do
+    field :type, :string, allow_nil?: false
+    field :name, :string, allow_nil?: false
+    field :email, :string, allow_nil?: false
+    field :age, :integer
+  end
+end
+
+defmodule AshOaskit.Test.Company do
+  @moduledoc """
+  TypedStruct for Company variant.
+  """
+
+  use Ash.TypedStruct
+
+  typed_struct do
+    field :type, :string, allow_nil?: false
+    field :company_name, :string, allow_nil?: false
+    field :tax_id, :string, allow_nil?: false
+    field :employee_count, :integer
+  end
+end
+
+defmodule AshOaskit.Test.Actor do
+  @moduledoc """
+  Union type for Actor (person or company) with discriminator.
+  """
+
+  use Ash.Type.NewType,
+    subtype_of: :union,
+    constraints: [
+      types: [
+        person: [
+          type: AshOaskit.Test.Person,
+          tag: :type,
+          tag_value: "person"
+        ],
+        company: [
+          type: AshOaskit.Test.Company,
+          tag: :type,
+          tag_value: "company"
+        ]
+      ]
+    ]
+end
+
 # ===========================================================================
 # Custom type with json_schema/1 callback
 # ===========================================================================
@@ -158,6 +217,8 @@ defmodule AshOaskit.Test.KitchenSink do
 
   Covers gaps identified in test resource analysis:
   - Union type attribute (ContentBlock)
+  - Typed struct attribute (Person) and a discriminated union of typed
+    structs (Actor: Person or Company)
   - Custom type with json_schema/1 (Coordinate)
   - Deeply nested embedded (Venue → Location → GeoPoint, 3 levels)
   - Array of embedded resources
@@ -189,6 +250,18 @@ defmodule AshOaskit.Test.KitchenSink do
       description "Polymorphic content block (text, image, or code)"
     end
 
+    # --- Union of typed structs with discriminator (Actor) ---
+    attribute :actor, AshOaskit.Test.Actor do
+      public? true
+      description "The actor (person or company) associated with this record"
+    end
+
+    # --- Typed struct as a direct attribute type ---
+    attribute :owner, AshOaskit.Test.Person do
+      public? true
+      description "The owner of this record"
+    end
+
     # --- Custom type with json_schema/1 ---
     attribute :coordinates, AshOaskit.Test.Coordinate do
       public? true