diff --git a/demo/apis.json b/demo/apis.json
index 8bb3941..d134377 100644
--- a/demo/apis.json
+++ b/demo/apis.json
@@ -27,5 +27,7 @@
   "APIC-671/APIC-671.yaml": { "type": "OAS 3.0", "mime": "application/yaml" },
   "APIC-743/APIC-743.yaml": { "type": "OAS 3.0", "mime": "application/yaml" },
   "shopper-products/shopper-products.yaml": { "type": "OAS 3.0", "mime": "application/yaml" },
-  "W-12142859/W-12142859.yaml": "OAS 2.0"
+  "W-12142859/W-12142859.yaml": "OAS 2.0",
+  "nulleable/nulleable.yaml": "OAS 3.0",
+  "nullable-test/nullable-test.yaml": { "type": "OAS 3.0", "mime": "application/yaml" }
 }
diff --git a/demo/index.js b/demo/index.js
index 8d50262..94d02a8 100644
--- a/demo/index.js
+++ b/demo/index.js
@@ -99,6 +99,8 @@ class ApiDemo extends ApiDemoPage {
 
   _apiListTemplate() {
     return [
+      ['nullable-test', 'Nullable Test (Comprehensive)'],
+      ['nulleable', 'Nulleable test'],
       ['grpc-test', 'GRPC test'],
       ['shopper-products', 'shopper-products'],
       ['demo-api', 'Demo API'],
diff --git a/demo/nullable-test/nullable-test.yaml b/demo/nullable-test/nullable-test.yaml
new file mode 100644
index 0000000..c1e2993
--- /dev/null
+++ b/demo/nullable-test/nullable-test.yaml
@@ -0,0 +1,340 @@
+openapi: 3.0.0
+info:
+  title: Nullable Types Test API
+  description: Comprehensive test for nullable rendering optimization
+  version: 1.0.0
+
+paths:
+  /test:
+    post:
+      summary: Test endpoint
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/TestRequest'
+      responses:
+        '200':
+          description: Success
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/TestResponse'
+
+components:
+  schemas:
+    # ============================================
+    # SCALAR NULLABLES (Should show "Type or null")
+    # ============================================
+    ScalarNullables:
+      type: object
+      description: All scalar types with nullable true - should render as "Type or null"
+      properties:
+        nullableString:
+          type: string
+          nullable: true
+          description: Should show "String or null"
+          example: "hello"
+        
+        nullableInteger:
+          type: integer
+          nullable: true
+          description: Should show "Integer or null"
+          example: 42
+        
+        nullableNumber:
+          type: number
+          nullable: true
+          description: Should show "Number or null"
+          example: 3.14
+        
+        nullableBoolean:
+          type: boolean
+          nullable: true
+          description: Should show "Boolean or null"
+          example: true
+        
+        nullableDateTime:
+          type: string
+          format: date-time
+          nullable: true
+          description: Should show "DateTime or null"
+          example: "2026-01-02T10:30:00Z"
+        
+        nullableDate:
+          type: string
+          format: date
+          nullable: true
+          description: Should show "Date or null"
+          example: "2026-01-02"
+        
+        nullableEmail:
+          type: string
+          format: email
+          nullable: true
+          description: Should show "String or null" (with format email)
+          example: "test@example.com"
+        
+        nullableUuid:
+          type: string
+          format: uuid
+          nullable: true
+          description: Should show "String or null" (with format uuid)
+          example: "550e8400-e29b-41d4-a716-446655440000"
+
+    # ============================================
+    # COMPLEX NULLABLES (Should keep Union selector)
+    # ============================================
+    ComplexNullables:
+      type: object
+      description: Complex types with nullable - should render as Union
+      properties:
+        nullableArray:
+          type: array
+          nullable: true
+          description: Should show "Array or null"
+          items:
+            type: string
+          example: ["item1", "item2"]
+        
+        nullableObject:
+          type: object
+          nullable: true
+          description: Should show "Object or null"
+          properties:
+            name:
+              type: string
+              example: "John Doe"
+            age:
+              type: integer
+              example: 30
+          example:
+            name: "Jane Smith"
+            age: 25
+        
+        nullableArrayOfObjects:
+          type: array
+          nullable: true
+          description: Should show "Array or null"
+          items:
+            type: object
+            properties:
+              id:
+                type: string
+                example: "uuid-123"
+              value:
+                type: number
+                example: 42.5
+          example:
+            - id: "obj-1"
+              value: 10.5
+            - id: "obj-2"
+              value: 20.3
+
+    # ============================================
+    # REAL UNIONS (Should keep Union selector)
+    # ============================================
+    RealUnions:
+      type: object
+      description: Real unions that are not just nullable
+      properties:
+        stringOrNumber:
+          description: Real union - should show Union selector
+          oneOf:
+            - type: string
+            - type: number
+        
+        multipleTypes:
+          description: Real union with 3+ types - should show Union selector
+          oneOf:
+            - type: string
+            - type: integer
+            - type: boolean
+        
+        objectOrString:
+          description: Real union - should show Union selector
+          anyOf:
+            - type: object
+              properties:
+                data:
+                  type: string
+            - type: string
+
+    # ============================================
+    # NESTED NULLABLES
+    # ============================================
+    NestedNullables:
+      type: object
+      description: Objects with nested nullable properties
+      properties:
+        user:
+          type: object
+          properties:
+            id:
+              type: string
+              description: Required user ID
+            email:
+              type: string
+              nullable: true
+              description: Optional email - should show "String or null"
+            phoneNumber:
+              type: string
+              nullable: true
+              description: Optional phone - should show "String or null"
+            metadata:
+              type: object
+              nullable: true
+              description: Optional metadata object - should show Union
+              properties:
+                created:
+                  type: string
+                  format: date-time
+                lastLogin:
+                  type: string
+                  format: date-time
+                  nullable: true
+          required:
+            - id
+
+    # ============================================
+    # ARRAYS WITH NULLABLE ITEMS
+    # ============================================
+    ArraysWithNullableItems:
+      type: object
+      description: Arrays containing nullable items
+      properties:
+        arrayOfNullableStrings:
+          type: array
+          description: Array of strings where each item can be null
+          items:
+            type: string
+            nullable: true
+        
+        arrayOfNullableObjects:
+          type: array
+          description: Array of objects where each object can be null
+          items:
+            type: object
+            nullable: true
+            properties:
+              name:
+                type: string
+              value:
+                type: number
+
+    # ============================================
+    # EDGE CASES
+    # ============================================
+    EdgeCases:
+      type: object
+      description: Edge cases and special scenarios
+      properties:
+        enumNullable:
+          type: string
+          enum: ["option1", "option2", "option3"]
+          nullable: true
+          description: Enum with nullable - should show "String or null"
+        
+        numberWithConstraints:
+          type: number
+          minimum: 0
+          maximum: 100
+          nullable: true
+          description: Number with constraints and nullable - should show "Number or null"
+        
+        stringWithPattern:
+          type: string
+          pattern: "^[A-Z]{3}$"
+          nullable: true
+          description: String with pattern and nullable - should show "String or null"
+        
+        readOnlyNullable:
+          type: string
+          nullable: true
+          readOnly: true
+          description: Read-only nullable field - should show "String or null"
+        
+        deprecatedNullable:
+          type: integer
+          nullable: true
+          deprecated: true
+          description: Deprecated nullable field - should show "Integer or null"
+
+    # ============================================
+    # COMBINED REQUEST/RESPONSE
+    # ============================================
+    TestRequest:
+      type: object
+      required:
+        - userId
+        - action
+      properties:
+        userId:
+          type: string
+          description: Required user ID
+        action:
+          type: string
+          enum: ["create", "update", "delete"]
+        timezone:
+          type: string
+          nullable: true
+          description: Client timezone (nullable) - should show "String or null"
+          example: "America/Los_Angeles"
+        metadata:
+          type: object
+          nullable: true
+          description: Optional metadata (nullable object) - should show "Object or null"
+          properties:
+            source:
+              type: string
+              example: "web-app"
+            timestamp:
+              type: string
+              format: date-time
+              example: "2026-01-02T10:30:00Z"
+        tags:
+          type: array
+          nullable: true
+          description: Optional tags (nullable array) - should show "Array or null"
+          items:
+            type: string
+      example:
+        userId: "user-123"
+        action: "create"
+        timezone: "America/Los_Angeles"
+        metadata:
+          source: "mobile-app"
+          timestamp: "2026-01-02T15:45:30Z"
+        tags: ["tag1", "tag2", "tag3"]
+
+    TestResponse:
+      type: object
+      properties:
+        success:
+          type: boolean
+        data:
+          type: object
+          nullable: true
+          description: Response data (nullable object) - should show "Object or null"
+          properties:
+            id:
+              type: string
+            status:
+              type: string
+        message:
+          type: string
+          nullable: true
+          description: Optional message - should show "String or null"
+        errorCode:
+          type: integer
+          nullable: true
+          description: Optional error code - should show "Integer or null"
+      example:
+        success: true
+        data:
+          id: "result-456"
+          status: "completed"
+        message: "Operation successful"
+        errorCode: null
+
diff --git a/demo/nulleable/nulleable.yaml b/demo/nulleable/nulleable.yaml
new file mode 100644
index 0000000..8684f67
--- /dev/null
+++ b/demo/nulleable/nulleable.yaml
@@ -0,0 +1,1632 @@
+openapi: 3.0.0
+
+info:
+  title: Einstein Bots API (BETA)
+  version: 'v5'
+
+servers:
+  - url: https://runtime-api-na-west.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - NA West
+  - url: https://runtime-api-na-east.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - NA East
+  - url: https://runtime-api-eu-west.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - EU West
+  - url: https://runtime-api-eu-east.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - EU East
+  - url: https://runtime-api-ap-west.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - AP West
+  - url: https://runtime-api-ap-east.prod.chatbots.sfdc.sh
+    description: Einstein Bots API - AP East
+
+paths:
+  /status:
+    get:
+      tags:
+        - 'health'
+      summary: 'Check the health status'
+      description: 'Returns whether the status of Einstein Bots API is up or down.'
+      operationId: 'getHealthStatus'
+      responses:
+        '200':
+          $ref: '#/components/responses/StatusResponse'
+        default:
+          $ref: '#/components/responses/ErrorResponse'
+
+  /v5.0.0/bots/{bot-id}/sessions:
+    post:
+      tags:
+        - 'bot'
+      summary: 'Start a session'
+      description: 'Send a message to the bots API to start a new session.'
+      operationId: 'startSession'
+      security:
+        - chatbotAuth: ['chatbot_api']
+        - jwtBearer: []
+      parameters:
+        - in: 'path'
+          name: 'bot-id'
+          description: 'ID of the Einstein Bot that you want to interact with.'
+          required: true
+          schema:
+            type: 'string'
+        - in: 'header'
+          name: 'X-Org-Id'
+          description: '18-character org ID of the Salesforce org associated with the bot.'
+          example: '00Dx0000000ALskEAG'
+          required: true
+          schema:
+            type: 'string'
+          allowEmptyValue: false
+        - in: 'header'
+          name: 'X-Request-ID'
+          description: 'Request ID. A UUID in string format created by you to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          required: true
+          schema:
+            type: 'string'
+      requestBody:
+        description: 'Request payload to initiate a session.'
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/InitMessageEnvelope'
+      responses:
+        '200':
+          $ref: '#/components/responses/SuccessfulResponse'
+        '400':
+          $ref: '#/components/responses/BadRequestError'
+        '401':
+          $ref: '#/components/responses/UnauthorizedError'
+        '403':
+          $ref: '#/components/responses/ForbiddenError'
+        '404':
+          $ref: '#/components/responses/NotFoundError'
+        '422':
+          $ref: '#/components/responses/RequestProcessingException'
+        '423':
+          $ref: '#/components/responses/ServerBusyError'
+        '429':
+          $ref: '#/components/responses/TooManyRequestsError'
+        '503':
+          $ref: '#/components/responses/ServiceUnavailable'
+        default:
+          $ref: '#/components/responses/ErrorResponse'
+
+  /v5.0.0/sessions/{session-id}/messages:
+    post:
+      tags:
+        - 'bot'
+      summary: 'Continue an active session'
+      description: 'Send a message to the bots API on an active session.'
+      operationId: 'continueSession'
+      security:
+        - chatbotAuth: ['chatbot_api']
+        - jwtBearer: []
+      parameters:
+        - in: 'path'
+          name: 'session-id'
+          description: 'ID of an active session. This is the `sessionId` returned by the bot when you start a session.'
+          required: true
+          schema:
+            type: 'string'
+        - in: 'header'
+          name: 'X-Org-Id'
+          description: '18-character org ID of the Salesforce org associated with the bot.'
+          example: '00Dx0000000ALskEAG'
+          required: true
+          schema:
+            type: 'string'
+          # allowEmptyValue: false
+        - in: 'header'
+          name: 'X-Request-ID'
+          description: 'Request ID. A UUID in string format created by you to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          required: true
+          schema:
+            type: 'string'
+        - in: 'header'
+          name: 'X-Runtime-CRC'
+          description: 'Internal runtime CRC. This is the `X-Runtime-CRC` value from previous response.'
+          schema:
+            type: 'string'
+      requestBody:
+        description: 'Request payload to continue the chat.'
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/ChatMessageEnvelope'
+      responses:
+        '200':
+          $ref: '#/components/responses/SuccessfulChatMessageResponse'
+        '400':
+          $ref: '#/components/responses/BadRequestError'
+        '401':
+          $ref: '#/components/responses/UnauthorizedError'
+        '403':
+          $ref: '#/components/responses/ForbiddenError'
+        '404':
+          $ref: '#/components/responses/NotFoundError'
+        '422':
+          $ref: '#/components/responses/RequestProcessingException'
+        '423':
+          $ref: '#/components/responses/ServerBusyError'
+        '429':
+          $ref: '#/components/responses/TooManyRequestsError'
+        '503':
+          $ref: '#/components/responses/ServiceUnavailable'
+        default:
+          $ref: '#/components/responses/ErrorResponse'
+
+  /v5.0.0/sessions/{session-id}:
+    delete:
+      tags:
+        - 'bot'
+      summary: 'End an active session'
+      description: 'Send a message to the bots API to end a session'
+      operationId: 'endSession'
+      security:
+        - chatbotAuth: ['chatbot_api']
+        - jwtBearer: []
+      parameters:
+        - in: 'path'
+          name: 'session-id'
+          description: 'ID of an active session. This is the `sessionId` returned by the bot when you start a session.'
+          required: true
+          schema:
+            type: 'string'
+        - in: 'header'
+          name: 'X-Org-Id'
+          description: '18-character org ID of the Salesforce org associated with the bot.'
+          example: '00Dx0000000ALskEAG'
+          required: true
+          schema:
+            type: 'string'
+          allowEmptyValue: false
+        - in: 'header'
+          name: 'X-Session-End-Reason'
+          description: 'Reason sesssion ended.'
+          example: 'Transfer'
+          required: true
+          schema:
+            $ref: '#/components/schemas/EndSessionReason'
+          allowEmptyValue: false
+        - in: 'header'
+          name: 'X-Request-ID'
+          description: 'Request ID. A UUID in string format created by you to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          required: true
+          schema:
+            type: 'string'
+        - in: 'header'
+          name: 'X-Runtime-CRC'
+          description: 'Internal runtime CRC. This is the `X-Runtime-CRC` value from previous response.'
+          schema:
+            type: 'string'
+      responses:
+        '200':
+          $ref: '#/components/responses/SuccessfulChatMessageResponse'
+        '400':
+          $ref: '#/components/responses/BadRequestError'
+        '401':
+          $ref: '#/components/responses/UnauthorizedError'
+        '403':
+          $ref: '#/components/responses/ForbiddenError'
+        '404':
+          $ref: '#/components/responses/NotFoundError'
+        '422':
+          $ref: '#/components/responses/RequestProcessingException'
+        '423':
+          $ref: '#/components/responses/ServerBusyError'
+        '429':
+          $ref: '#/components/responses/TooManyRequestsError'
+        '503':
+          $ref: '#/components/responses/ServiceUnavailable'
+        default:
+          $ref: '#/components/responses/ErrorResponse'
+
+components:
+  securitySchemes:
+    chatbotAuth:
+      type: oauth2
+      flows:
+        authorizationCode:
+          authorizationUrl: https://login.salesforce.com/services/oauth2/authorize
+          tokenUrl: https://login.salesforce.com/services/oauth2/token
+          scopes:
+            chatbot_api: 'Access Chatbot Apis'
+        implicit:
+          authorizationUrl: https://login.salesforce.com/services/oauth2/authorize
+          scopes:
+            chatbot_api: 'Access Chatbot Apis'
+    jwtBearer:
+      type: http
+      scheme: bearer
+      description: 'Salesforce OAuth access token obtained using the JWT Bearer flow. Use the `chatbot_api` scope with this flow to enable access to the Einstein Bots services.'
+
+  schemas:
+    ResponseSessionId:
+      description: 'Bot runtime session ID.'
+      type: 'string'
+      example: '57904eb6-5352-4c5e-adf6-5f100572cf5d'
+      nullable: false
+
+    ExternalSessionKey:
+      description: "UUID in string format for the conversation. You can use this parameter to trace the conversation in your bot's event logs."
+      type: 'string'
+      example: '57904eb6-5352-4c5e-adf6-5f100572cf5d'
+      nullable: false
+
+    BotVersion:
+      description: 'Bot configuration version.'
+      type: 'string'
+      example: '0X9RM0000004CD00AM'
+
+    InitMessageEnvelope:
+      type: 'object'
+      properties:
+        externalSessionKey:
+          $ref: '#/components/schemas/ExternalSessionKey'
+        message:
+          $ref: '#/components/schemas/TextInitMessage'
+        forceConfig:
+          $ref: '#/components/schemas/ForceConfig'
+        responseOptions:
+          $ref: '#/components/schemas/ResponseOptions'
+        tz:
+          description: 'Client timezone where the customer starts the chat.'
+          type: 'string'
+          nullable: true
+          example: 'America/Los_Angeles'
+        variables:
+          $ref: '#/components/schemas/Variables'
+        referrers:
+          description: 'Array of referrers of transferring the session to another bot.'
+          type: 'array'
+          items:
+            $ref: '#/components/schemas/Referrer'
+          nullable: true
+        richContentCapabilities:
+          $ref: '#/components/schemas/RichContentCapability'
+      required:
+        - 'forceConfig'
+        - 'externalSessionKey'
+      additionalProperties: false
+
+    RichContentCapability:
+      description: 'Rich content configuration supported by the client.'
+      type: 'object'
+      properties:
+        messageTypes:
+          description: 'Array of message types supporting rich content and their output formats.'
+          type: 'array'
+          minimum: 1
+          items:
+            $ref: '#/components/schemas/MessageTypeCapability'
+      required:
+        - messageTypes
+
+    MessageTypeCapability:
+      type: 'object'
+      properties:
+        messageType:
+          $ref: '#/components/schemas/MessageType'
+        formatTypes:
+          description: 'Array of output format types.'
+          type: 'array'
+          minimum: 1
+          items:
+            $ref: '#/components/schemas/FormatTypeCapability'
+      required:
+        - messageType
+        - formatTypes
+
+    FormatTypeCapability:
+      type: 'object'
+      properties:
+        formatType:
+          $ref: '#/components/schemas/FormatType'
+      required:
+        - formatType
+
+    FormatType:
+      description: |
+        Message format that is supported by the message type.
+
+        * `Attachments`—Shows the attachment as a downloadable file (rich content).
+        * `text`—Shows file as a URL link. Use this type if your client doesn’t support rich content.
+      type: 'string'
+      enum: ['Attachments', 'Text']
+      example: 'Attachments'
+
+    MessageType:
+      description: |
+        Message type that supports rich content output formats.
+
+        * `StaticContentMessage`—Represents static or non-interactive content, such as links and attachments.
+      type: 'string'
+      enum: ['StaticContentMessage']
+      example: 'StaticContentMessage'
+
+    ChatMessageEnvelope:
+      type: 'object'
+      properties:
+        message:
+          description: 'Message to the bot.'
+          oneOf:
+            - $ref: '#/components/schemas/ChoiceMessage'
+            - $ref: '#/components/schemas/TextMessage'
+            - $ref: '#/components/schemas/TransferSucceededRequestMessage'
+            - $ref: '#/components/schemas/TransferFailedRequestMessage'
+            - $ref: '#/components/schemas/RedirectMessage'
+        responseOptions:
+          $ref: '#/components/schemas/ResponseOptions'
+      required:
+        - 'message'
+      additionalProperties: false
+
+    ResponseEnvelope:
+      type: 'object'
+      properties:
+        sessionId:
+          $ref: '#/components/schemas/ResponseSessionId'
+        botVersion:
+          $ref: '#/components/schemas/BotVersion'
+        processedSequenceIds:
+          description: 'Sequence IDs of messages that the bot processed. Except for the initial request to start the session, all requests require a `sequenceId`.'
+          type: 'array'
+          items:
+            format: 'int64'
+            type: 'integer'
+            example: 1
+        messages:
+          description: 'Messages from the bot.'
+          type: 'array'
+          minimum: 0
+          items:
+            oneOf:
+              - $ref: '#/components/schemas/TextResponseMessage'
+              - $ref: '#/components/schemas/ChoicesResponseMessage'
+              - $ref: '#/components/schemas/StaticContentMessage'
+              - $ref: '#/components/schemas/EscalateResponseMessage'
+              - $ref: '#/components/schemas/SessionEndedResponseMessage'
+        variables:
+          $ref: '#/components/schemas/Variables'
+        metrics:
+          description: 'Session metrics.'
+          type: 'object'
+          additionalProperties: true
+        intents:
+          $ref: '#/components/schemas/Intents'
+        entities:
+          $ref: '#/components/schemas/Entities'
+        _links:
+          $ref: '#/components/schemas/Links'
+      required:
+        - 'sessionId'
+        - 'botVersion'
+        - 'processedSequenceIds'
+        - 'messages'
+        - '_links'
+      additionalProperties: false
+
+    ChatMessageResponseEnvelope:
+      type: 'object'
+      properties:
+        botVersion:
+          $ref: '#/components/schemas/BotVersion'
+        processedSequenceIds:
+          description: 'Sequence IDs of processed messages.'
+          type: 'array'
+          items:
+            format: 'int64'
+            type: 'integer'
+            example: 1, 2
+        messages:
+          description: 'Messages from the bot.'
+          type: 'array'
+          minimum: 0
+          items:
+            oneOf:
+              - $ref: '#/components/schemas/TextResponseMessage'
+              - $ref: '#/components/schemas/ChoicesResponseMessage'
+              - $ref: '#/components/schemas/StaticContentMessage'
+              - $ref: '#/components/schemas/EscalateResponseMessage'
+              - $ref: '#/components/schemas/SessionEndedResponseMessage'
+        variables:
+          $ref: '#/components/schemas/Variables'
+        metrics:
+          description: 'Session metrics.'
+          type: 'object'
+          additionalProperties: true
+        intents:
+          $ref: '#/components/schemas/Intents'
+        entities:
+          $ref: '#/components/schemas/Entities'
+        _links:
+          $ref: '#/components/schemas/Links'
+      required:
+        - 'botVersion'
+        - 'processedSequenceIds'
+        - 'messages'
+        - '_links'
+      additionalProperties: false
+
+    StaticContentMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type of message with static (non-interactive) content.'
+          type: 'string'
+          enum: ['messageDefinition']
+        id:
+          $ref: '#/components/schemas/MessageId'
+        schedule:
+          $ref: '#/components/schemas/Schedule'
+        messageType:
+          $ref: '#/components/schemas/MessageType'
+        references:
+          type: 'array'
+          description: 'Array of Salesforce records.'
+          items:
+            $ref: '#/components/schemas/RecordReference'
+        staticContent:
+          description: 'Static content, such as files, delivered to the client.'
+          anyOf:
+            - $ref: '#/components/schemas/StaticContentAttachments'
+            - $ref: '#/components/schemas/StaticContentText'
+      required:
+        - 'id'
+        - 'type'
+        - 'messageType'
+        - 'staticContent'
+
+    StaticContentText:
+      type: 'object'
+      properties:
+        formatType:
+          type: 'string'
+          description: 'Format type of files that appear as a URL. The customer needs to go to the URL to access the file. This is in text format.'
+          example: 'Text'
+          enum: ['Text']
+        text:
+          $ref: '#/components/schemas/Text'
+      required:
+        - 'formatType'
+        - 'text'
+
+    StaticContentAttachments:
+      type: 'object'
+      properties:
+        formatType:
+          type: 'string'
+          description: 'Format type of files that appear as downloadable attachments. This is in rich content format.'
+          example: 'Attachments'
+          enum: ['Attachments']
+        attachments:
+          type: 'array'
+          description: 'Array of file attachments with a message.'
+          minItems: 1
+          items:
+            $ref: '#/components/schemas/Attachment'
+      required:
+        - 'formatType'
+        - 'attachments'
+
+    Attachment:
+      type: 'object'
+      properties:
+        id:
+          $ref: '#/components/schemas/AttachmentId'
+        name:
+          type: 'string'
+          description: 'Name of the file sent as an attachment.'
+        mimeType:
+          $ref: '#/components/schemas/MimeType'
+        url:
+          $ref: '#/components/schemas/Url'
+        referenceId:
+          $ref: '#/components/schemas/ReferenceId'
+      required:
+        - id
+        - name
+        - mimeType
+        - url
+      additionalProperties: false
+
+    Text:
+      description: 'URL where the customer can access the file.'
+      type: 'string'
+
+    MimeType:
+      description: 'Mime type of the attachment.'
+      type: 'string'
+
+    Url:
+      description: 'URL to the file.'
+      type: 'string'
+
+    RecordId:
+      type: 'string'
+      description: 'ID of an Salesforce record.'
+      example: '00P2S000005qKg1'
+
+    ReferenceId:
+      type: 'string'
+      description: 'ID of the reference to the static content record.'
+      example: 'cbd4e3fe-f210-43b8-a4b7-dd77e39ee5e1'
+
+    AttachmentId:
+      type: 'string'
+      description: 'ID of the attachment.'
+      example: 'cbd4e3fe-f210-43b8-a4b7-dd77e39ee5e1'
+
+    RecordReference:
+      type: 'object'
+      properties:
+        id:
+          $ref: '#/components/schemas/ReferenceId'
+        recordId:
+          $ref: '#/components/schemas/RecordId'
+      required:
+        - 'id'
+        - 'recordId'
+      additionalProperties: false
+
+    MessageId:
+      description: 'UUID that references this message.'
+      type: 'string'
+      example: 'a133c185-73a7-4adf-b6d9-b7fd62babb4e'
+
+    SequenceId:
+      description: 'Client generated sequence number of the message in a session. Increase this number for each subsequent message.'
+      format: 'int64'
+      type: 'integer'
+      example: 1
+
+    Intents:
+      description: |
+        Array of the intents detected by the bot when processing the request. For a bot, "intent" refers to the goal the customer 
+        (see [Use Intents to Understand Your Customers](https://help.salesforce.com/s/articleView?id=sf.bots_service_train_bot.htm&type=5&_ga=2.5901875.1281711304.1657558186-1967832163.1652719780)).
+      type: 'array'
+      minimum: 0
+      items:
+        $ref: '#/components/schemas/NormalizedIntent'
+
+    Entities:
+      description: 'Array of all entities detected by the bot when processing this request. For a bot, "Entities" refer to the modifiers the customer uses to describe their issue and intent is what they really mean.'
+      type: 'array'
+      minimum: 0
+      items:
+        $ref: '#/components/schemas/NormalizedEntity'
+
+    NormalizedIntent:
+      type: 'object'
+      properties:
+        label:
+          description: 'Name or ID of the intent.'
+          type: 'string'
+        confidenceScore:
+          description: 'Probability number that the AI assigns to this intent.'
+          type: 'number'
+        intentSource:
+          $ref: '#/components/schemas/IntentSource'
+      required:
+        - 'label'
+        - 'confidenceScore'
+        - 'intentSource'
+      additionalProperties: false
+
+    NormalizedEntity:
+      type: 'object'
+      properties:
+        confidenceScore:
+          description: 'Probability number that the AI assigns to this entity.'
+          type: 'number'
+        value:
+          description: 'Value of the entity that the customer enters.'
+          type: 'string'
+          example: 'TBD'
+        type:
+          $ref: '#/components/schemas/EntityType'
+        entitySource:
+          $ref: '#/components/schemas/EntitySource'
+      required:
+        - 'confidenceScore'
+        - 'value'
+        - 'type'
+      additionalProperties: false
+
+    EntityType:
+      description: 'System or custom entity Type ([What’s an Entity?](https://help.salesforce.com/s/articleView?id=sf.bots_service_whats_an_entity.htm&type=5)).'
+      type: 'string'
+      example: 'TBD'
+
+    IntentSource:
+      description: |
+        Prediction system that detects the intent. 
+
+        * `DIRECT`—Utterance search or an exact match
+        * `CORE_NLP`—Third-party Natural Language Processing (NLP)
+        * `EINSTEIN_NLP`—Einstein NLP
+      type: 'string'
+      enum:
+        - 'DIRECT'
+        - 'CORE_NLP'
+        - 'EINSTEIN_NLP'
+
+    EntitySource:
+      description: |
+        "Prediction system that detects the entity. The Bot API can call NLPs or it can figure out the entity by itself."
+
+        * `BOT_SERVICE`—Bot detects entity without Natural Language Processing (NLP) 
+        * `CORE_NLP`—Third-party NLP
+        * `EINSTEIN_NLP`—Einstein NLP
+      type: 'string'
+      enum:
+        - 'BOT_SERVICE'
+        - 'CORE_NLP'
+        - 'EINSTEIN_NLP'
+
+    Links:
+      description: 'List of Einstein Bots API endpoints for HATEOS compliancy.'
+      type: 'object'
+      properties:
+        self:
+          $ref: '#/components/schemas/SelfLink'
+        messages:
+          $ref: '#/components/schemas/MessageLink'
+        session:
+          $ref: '#/components/schemas/EndSessionLink'
+      required:
+        - 'self'
+      additionalProperties: false
+
+    SelfLink:
+      description: 'Endpoint of this request.'
+      type: 'object'
+      properties:
+        href:
+          description: 'URL of the endpoint.'
+          type: 'string'
+          example: 'https://runtime-api-ap-east.prod.chatbots.sfdc.sh/v5.0.0/bots/{bot-id}/sessions'
+
+    MessageLink:
+      description: 'Endpoint to continue an active session.'
+      type: 'object'
+      properties:
+        href:
+          description: 'URL of the endpoint.'
+          type: 'string'
+          example: 'https://runtime-api-ap-east.prod.chatbots.sfdc.sh/v5.0.0/sessions/{session-id}/messages'
+
+    EndSessionLink:
+      description: 'Endpoint to end a session.'
+      type: 'object'
+      properties:
+        href:
+          description: 'URL of the endpoint.'
+          type: 'string'
+          example: 'https://runtime-api-ap-east.prod.chatbots.sfdc.sh/v5.0.0/sessions/{session-id}'
+
+    InReplyToMessageId:
+      description: 'Message ID of the previous response you are replying to.'
+      type: 'string'
+      example: 'a133c185-73a7-4adf-b6d9-b7fd62babb4e'
+
+    BooleanVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'isShipped'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['boolean']
+          example: 'boolean'
+        value:
+          description: 'Variable value.'
+          type: 'boolean'
+          nullable: true
+          example: true
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    DateVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'orderDate'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['date']
+          example: 'date'
+        value:
+          description: "Variable value in format ISO_LOCAL_DATE 'YYYY-MM-DD'."
+          type: 'string'
+          nullable: true
+          example: '2021-09-21'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    DateTimeVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'orderDateTime'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['dateTime']
+          example: 'dateTime'
+        value:
+          description: "Variable value in format ISO_LOCAL_DATE_TIME 'YYYY-MM-DDTHH:MM:SS'."
+          type: 'string'
+          nullable: true
+          example: '2018-09-21T14:30:00'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    MoneyVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'orderAmount'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['money']
+          example: 'money'
+        value:
+          description: 'Variable value in format $3_letter_currency_code $amount.'
+          type: 'string'
+          nullable: true
+          example: 'USD 10.40'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    NumberVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'qty'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['number']
+          example: 'number'
+        value:
+          description: 'Variable value.'
+          type: 'number'
+          nullable: true
+          example: 10
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    TextVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'note'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['text']
+          example: 'text'
+        value:
+          description: 'Variable value.'
+          type: 'string'
+          nullable: true
+          example: 'Thanks for your order!'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    ObjectVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'contact'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['object']
+          example: 'object'
+        value:
+          description: 'Variable value.'
+          nullable: true
+          allOf:
+            - $ref: '#/components/schemas/Variables'
+          example: [{ 'name': 'fullName', 'type': 'text', 'value': 'Matt Smith' }]
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    RefVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'target'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['ref']
+          example: 'ref'
+        value:
+          description: 'Variable value.'
+          type: 'string'
+          nullable: true
+          example: '1M5xx000000000BCAQ'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    ListVariable:
+      type: 'object'
+      properties:
+        name:
+          description: 'API name of a variable defined in the bot definition.'
+          type: 'string'
+          example: 'target'
+        type:
+          description: 'Variable type.'
+          type: 'string'
+          enum: ['list']
+          example: 'list'
+        value:
+          description: 'Array of objects with variable type and value.'
+          type: 'array'
+          nullable: true
+          example: [{ 'type': 'ref', 'value': '1M5xx000000000BCAQ' }]
+          items:
+            type: 'object'
+            properties:
+              type:
+                description: 'Variable type in bot definition.'
+                type: 'string'
+                example: 'ref'
+              value:
+                description: 'Variable value.'
+                type: 'string'
+                example: '1M5xx000000000BCAQ'
+      required:
+        - 'name'
+        - 'type'
+        - 'value'
+      additionalProperties: false
+
+    Variables:
+      type: 'array'
+      description: 'Array of custom and context variables passed to the bot when initiating a session (see [What’s a Variable?](https://help.salesforce.com/s/articleView?id=sf.bots_service_whats_a_variable.htm&type=5&_ga=2.50520745.1281711304.1657558186-1967832163.1652719780)).'
+      items:
+        anyOf:
+          - $ref: '#/components/schemas/BooleanVariable'
+          - $ref: '#/components/schemas/DateVariable'
+          - $ref: '#/components/schemas/DateTimeVariable'
+          - $ref: '#/components/schemas/MoneyVariable'
+          - $ref: '#/components/schemas/NumberVariable'
+          - $ref: '#/components/schemas/TextVariable'
+          - $ref: '#/components/schemas/ObjectVariable'
+          - $ref: '#/components/schemas/RefVariable'
+          - $ref: '#/components/schemas/ListVariable'
+      nullable: true
+
+    Referrer:
+      type: 'object'
+      properties:
+        type:
+          description: 'Referrer type.'
+          type: 'string'
+          enum: ['Salesforce:Core:Bot:Id', 'Salesforce:BotRuntime:Session:Id']
+          example: 'Salesforce:Core:Bot:Id'
+        value:
+          type: 'string'
+          description: 'ID of referrer.'
+          example: 'string'
+      required:
+        - 'type'
+        - 'value'
+
+    TransferFailedRequestMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type for the client to inform the bot that the client failed to transfer the session to another target.'
+          type: 'string'
+          enum: ['transferFailed']
+          example: 'transferFailed'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        inReplyToMessageId:
+          $ref: '#/components/schemas/InReplyToMessageId'
+        reason:
+          description: 'Reason for the failed transfer.'
+          type: 'string'
+          enum: ['NoAgentAvailable', 'Error']
+          example: 'NoAgentAvailable'
+        description:
+          description: 'Description of why the transfer failed.'
+          type: 'string'
+          nullable: true
+      required:
+        - 'type'
+        - 'sequenceId'
+        - 'reason'
+      additionalProperties: false
+
+    TransferSucceededRequestMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type for the client to inform the bot that the client successfully transfered the session to another target.'
+          type: 'string'
+          enum: ['transferSucceeded']
+          example: 'transferSucceeded'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        inReplyToMessageId:
+          $ref: '#/components/schemas/InReplyToMessageId'
+      required:
+        - 'type'
+        - 'sequenceId'
+      additionalProperties: false
+
+    TextInitMessage:
+      type: 'object'
+      properties:
+        text:
+          description: 'Initial message from the customer to the bot to begin a session.'
+          type: 'string'
+          example: 'Hello'
+      additionalProperties: false
+
+    # Used in private spec only
+    EndSessionMessage:
+      type: 'object'
+      description: 'Client request to end the session.'
+      properties:
+        type:
+          description: 'Message type for the client requesting the session to end.'
+          type: 'string'
+          enum: ['endSession']
+          example: 'endSession'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        inReplyToMessageId:
+          $ref: '#/components/schemas/InReplyToMessageId'
+        reason:
+          $ref: '#/components/schemas/EndSessionReason'
+      required:
+        - 'type'
+        - 'sequenceId'
+        - 'reason'
+      additionalProperties: false
+
+    EndSessionReason:
+      type: 'string'
+      enum:
+        - 'UserRequest'
+        - 'Transfer'
+        - 'Expiration'
+        - 'Error'
+        - 'Other'
+      example: 'Transfer'
+      nullable: false
+
+    TextMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type for replying to the bot through text.'
+          type: 'string'
+          enum: ['text']
+          example: 'text'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        inReplyToMessageId:
+          $ref: '#/components/schemas/InReplyToMessageId'
+        text:
+          description: 'Text reply to the bot. You can answer a question with choices by typing the `choiceLabel` in a text message, instead of clicking an answer in the widget.'
+          type: 'string'
+      required:
+        - 'type'
+        - 'sequenceId'
+        - 'text'
+      additionalProperties: false
+
+    ChoiceMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type for answering a question with choices from the bot.'
+          type: 'string'
+          enum: ['choice']
+          example: 'choice'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        inReplyToMessageId:
+          $ref: '#/components/schemas/InReplyToMessageId'
+        choiceIndex:
+          description: 'Index or alias of the chosen answer. The index starts with 1. Either `choiceIndex` or `choiceId` is required.'
+          type: 'integer'
+          minimum: 1
+          example: 1
+          nullable: true
+        choiceId:
+          description: 'ID of the answer when you answer by clicking a choice button. Either `choiceIndex` or `choiceId` is required.'
+          type: 'string'
+          example: '8a9a745f-0c09-4b13-955c-1ab9e06c7ad7'
+          nullable: true
+      required:
+        - 'type'
+        - 'sequenceId'
+      additionalProperties: false
+
+    RedirectMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type for the redirecting the client to another bot flow.'
+          type: 'string'
+          enum: ['redirect']
+          example: 'redirect'
+        sequenceId:
+          $ref: '#/components/schemas/SequenceId'
+        dialogId:
+          type: 'string'
+          description: 'Dialog ID to redirect to.'
+          example: '68f934fb-e022-37a7-612e-b74fc87191d9'
+      required:
+        - 'type'
+        - 'sequenceId'
+        - 'dialogId'
+      additionalProperties: false
+
+    Schedule:
+      type: 'object'
+      properties:
+        responseDelayMilliseconds:
+          description: "Delay in ms to display the bot's message to the user. This parameter is set by the bot admin when creating the bot."
+          type: 'integer'
+          format: 'int32'
+          example: 1200
+      required:
+        - 'responseDelayMilliseconds'
+      additionalProperties: false
+
+    SessionEndedResponseMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type informing that the session ended.'
+          type: 'string'
+          enum: ['sessionEnded']
+          example: 'sessionEnded'
+        id:
+          $ref: '#/components/schemas/MessageId'
+        reason:
+          description: 'Reason the session ended.'
+          type: 'string'
+          enum:
+            [
+              'ClientRequest',
+              'TransferFailedNotConfigured',
+              'Action',
+              'Error',
+              'InfiniteLoopDetected',
+            ]
+          example: 'ClientRequest'
+          nullable: false
+        schedule:
+          $ref: '#/components/schemas/Schedule'
+      required:
+        - 'type'
+        - 'id'
+        - 'reason'
+      additionalProperties: false
+
+    TextResponseMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type of a text message to the customer.'
+          type: 'string'
+          enum: ['text']
+          example: 'text'
+        id:
+          $ref: '#/components/schemas/MessageId'
+        text:
+          description: 'Message from the bot.'
+          type: 'string'
+          example: 'Hello world!'
+        schedule:
+          $ref: '#/components/schemas/Schedule'
+      required:
+        - 'type'
+        - 'id'
+        - 'text'
+      additionalProperties: false
+
+    ChoicesResponseMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type of a question with choices.'
+          type: 'string'
+          enum: ['choices']
+          example: 'choices'
+        id:
+          $ref: '#/components/schemas/MessageId'
+        choices:
+          description: 'Array of answers to choose from.'
+          type: 'array'
+          minItems: 1
+          items:
+            type: 'object'
+            description: 'Choice'
+            properties:
+              label:
+                description: 'Choice label.'
+                type: 'string'
+                example: 'Order Status'
+              alias:
+                description: 'Choice alias, for example, a number to represent the choice.'
+                type: 'string'
+                example: '1'
+                nullable: true
+              id:
+                description: 'Choice ID.'
+                type: 'string'
+                example: '8a9a745f-0c09-4b13-955c-1ab9e06c7ad7'
+            required:
+              - 'label'
+              - 'id'
+        widget:
+          description: |
+            "Widget type of how answers appear in the client.
+
+            * `buttons`—Answers appear in clickable pill boxes.
+            * `menu`—Answers appear in clickable boxes vertically stacked."
+          type: 'string'
+          enum: ['buttons', 'menu']
+          example: 'buttons'
+        schedule:
+          $ref: '#/components/schemas/Schedule'
+      required:
+        - 'type'
+        - 'id'
+        - 'choices'
+        - 'widget'
+      additionalProperties: false
+
+    EscalateResponseMessage:
+      type: 'object'
+      properties:
+        type:
+          description: 'Message type of an escalation message.'
+          type: 'string'
+          enum: ['escalate']
+          example: 'escalate'
+        id:
+          $ref: '#/components/schemas/MessageId'
+        schedule:
+          $ref: '#/components/schemas/Schedule'
+        targets:
+          type: 'array'
+          minimum: 0
+          description: 'Array of transfer targets.'
+          items:
+            type: 'object'
+            properties:
+              type:
+                type: 'string'
+                description: Type of the transfer target.
+                enum:
+                  [
+                    'Salesforce:Core:Bot:Id',
+                    'Salesforce:Core:Queue:Id',
+                    'Salesforce:Core:Skill:Id',
+                    'Salesforce:Core:Flow:Id',
+                  ]
+                example: 'Salesforce:Core:Bot:Id'
+              value:
+                type: 'string'
+                description: 'ID of the transfer target.'
+            required:
+              - 'value'
+              - 'type'
+            nullable: false
+            additionalProperties: false
+          nullable: false
+      required:
+        - 'type'
+        - 'id'
+        - 'targets'
+      additionalProperties: false
+
+    ForceConfig:
+      type: 'object'
+      description: 'API configuration parameters.'
+      properties:
+        endpoint:
+          description: 'Instance URL of your Salesforce org. You can find the value in the **ForceConfig Endpoint** field of the **Add Connection** dialog when you add the connected app to the bot (see [Get Started with Einstein Bot API](https://developer.salesforce.com/docs/service/einstein-bot-api/guide/prerequisites.html)).'
+          type: 'string'
+          example: 'https://d5e000009s7bceah-dev-ed.my.salesforce.com/'
+      required:
+        - 'endpoint'
+      additionalProperties: true
+
+    ResponseOptions:
+      type: 'object'
+      description: 'Configuration of additional information returned in the response payload.'
+      properties:
+        variables:
+          $ref: '#/components/schemas/ResponseOptionsVariables'
+        metrics:
+          type: 'boolean'
+          description: 'Indicates whether or not to include metrics in the response.'
+        intents:
+          type: 'boolean'
+          description: 'Indicates whether or not to include all intents detected when processing the current request.'
+        entities:
+          type: 'boolean'
+          description: 'Indicates whether or not to include all entities detected when processing the current request.'
+      additionalProperties: false
+
+    ResponseOptionsVariables:
+      type: 'object'
+      description: 'Variables returned in the response.'
+      properties:
+        include:
+          type: 'boolean'
+          example: true
+          description: 'Indicates whether or not to include variables in the response.'
+        filter:
+          type: 'array'
+          example: ['OrderQty', 'OrderType']
+          description: 'Array of variable names to limit the returned variables. If missing, null, or empty, no filtering is applied.'
+          items:
+            type: 'string'
+            description: 'Variable name to filter the returned variables on.'
+            example: 'OrderQty'
+          nullable: true
+        onlyChanged:
+          type: 'boolean'
+          example: true
+          description: 'Indicates whether or not the response contains only changed variables.'
+      required:
+        - 'include'
+        - 'onlyChanged'
+      additionalProperties: false
+
+    Status:
+      type: 'object'
+      properties:
+        status:
+          type: 'string'
+          description: 'Health status of Einstein Bots API.'
+          enum: ['UP', 'DOWN']
+          example: 'UP'
+      required:
+        - 'status'
+      additionalProperties: false
+
+    # Do not show examples here as this Error schema is used
+    # generically for all error codes.
+    # The examples specific to the error code are shown elsewhere.
+    Error:
+      type: 'object'
+      properties:
+        status:
+          description: 'HTTP status.'
+          type: 'integer'
+          format: 'int32'
+          # example: 500
+        path:
+          description: 'Request path.'
+          type: 'string'
+          # example: "/v1/00DRM00000067To/chatbots/HelloWorldBot/messages"
+        requestId:
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          type: 'string'
+          # example: "19c056ab-d909-49df-b976-65e56b6ab214"
+        error:
+          description: 'Error class name.'
+          type: 'string'
+          # example: "NullPointerException"
+        message:
+          description: 'Exception message.'
+          type: 'string'
+          # example: "Something went wrong"
+        timestamp:
+          description: 'Unix timestamp.'
+          type: 'integer'
+          format: 'int64'
+          # example: 1531245973799
+      required:
+        - 'status'
+        - 'path'
+        - 'requestId'
+        - 'error'
+        - 'message'
+        - 'timestamp'
+      additionalProperties: true
+
+  responses:
+    StatusResponse:
+      description: 'OK'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Status'
+
+    ErrorResponse:
+      description: 'Something went wrong'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    SuccessfulResponse:
+      description: 'OK'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/ResponseEnvelope'
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+        'X-Runtime-CRC':
+          description: 'Internal runtime CRC unique to the request.'
+          schema:
+            type: 'string'
+        'X-Bot-Mode':
+          description: 'Bot mode.'
+          example: 'default'
+          schema:
+            type: 'string'
+
+    SuccessfulChatMessageResponse:
+      description: 'OK'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/ChatMessageResponseEnvelope'
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+        'X-Runtime-CRC':
+          description: 'Internal runtime CRC.'
+          schema:
+            type: 'string'
+
+    BadRequestError:
+      description: 'Bad Request'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 400
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'BadRequestError'
+            message: 'Bad Request'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    UnauthorizedError:
+      description: 'Access bearer token is missing or invalid'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 401
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'UnauthorizedError'
+            message: 'Access bearer token is missing or invalid'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    ForbiddenError:
+      description: 'User forbidden from accessing the resource'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 403
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'ForbiddenError'
+            message: 'User forbidden from accessing the resource'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    NotFoundError:
+      description: 'Resource not found'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 404
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'NotFoundError'
+            message: 'Resource not found'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: 36a73651-a46d-4d16-9a8a-fd436ed62e1a
+          schema:
+            type: 'string'
+
+    NotAvailableError:
+      description: 'Resource not available at the time of the request'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 410
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'NotAvailableError'
+            message: 'Resource not available at the time of the request'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    RequestProcessingException:
+      description: 'Any exception that occurred during the request execution'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 422
+            path: 'v4.0.0/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'RequestProcessingException'
+            message: 'Cannot determine the active version for the bot'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    ServerBusyError:
+      description: 'Server is busy and cannot process the request at this time'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 423
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'ServerBusyError'
+            message: 'Server is busy and cannot process the request at this time'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    TooManyRequestsError:
+      description: 'Too many requests for the server to handle'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 429
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'TooManyRequestsError'
+            message: 'Too many requests for the server to handle'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
+
+    ServiceUnavailable:
+      description: 'Service is unavailable possibly because Apex or Flow calls timed out'
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Error'
+          example:
+            status: 503
+            path: '/v1/00DRM00000067To/chatbots/HelloWorldBot/messages'
+            requestId: '19c056ab-d909-49df-b976-65e56b6ab214'
+            error: 'ServiceUnavailable'
+            message: 'Service is unavailable possibly because Apex/Flow calls timed out'
+            timestamp: 1531245973799
+      headers:
+        'X-Request-ID':
+          description: 'Request ID. A UUID in string format to help with request tracking.'
+          example: '36a73651-a46d-4d16-9a8a-fd436ed62e1a'
+          schema:
+            type: 'string'
diff --git a/src/ApiTypeDocument.js b/src/ApiTypeDocument.js
index 66cda01..d26732b 100644
--- a/src/ApiTypeDocument.js
+++ b/src/ApiTypeDocument.js
@@ -448,9 +448,16 @@ export class ApiTypeDocument extends PropertyDocumentMixin(LitElement) {
     } else if (
       this._hasType(type, shapesKey.UnionShape)
     ) {
-      isUnion = true;
-      key = this._getAmfKey(shapesKey.anyOf);
-      this.unionTypes = this._computeTypes(type, key);
+      // Check if this is a nullable union (type | null) which should be rendered as scalar
+      const nullableCheck = this._checkNullableUnion(type);
+      if (nullableCheck && nullableCheck.isNullable) {
+        // Treat nullable types as scalar for cleaner rendering
+        isScalar = true;
+      } else {
+        isUnion = true;
+        key = this._getAmfKey(shapesKey.anyOf);
+        this.unionTypes = this._computeTypes(type, key);
+      }
     } else if (this._hasProperty(type, this.ns.w3.shacl.xone)) {
       isOneOf = true;
       key = this._getAmfKey(this.ns.w3.shacl.xone);
diff --git a/src/PropertyDocumentMixin.d.ts b/src/PropertyDocumentMixin.d.ts
index 810bafb..ed80bff 100644
--- a/src/PropertyDocumentMixin.d.ts
+++ b/src/PropertyDocumentMixin.d.ts
@@ -49,6 +49,15 @@ interface PropertyDocumentMixin extends AmfHelperMixin {
    */
   graph: boolean;
 
+  /**
+   * Checks if a union shape represents a nullable type (union with null).
+   * A nullable type is a union of exactly 2 members where one is NilShape.
+   * 
+   * @param range AMF range object (should be UnionShape)
+   * @returns Returns {baseType, isNullable: true} if nullable, undefined otherwise
+   */
+  _checkNullableUnion(range: any): { baseType: any; isNullable: boolean } | undefined;
+
   /**
    * Computes type from a `http://raml.org/vocabularies/shapes#range` object
    *
diff --git a/src/PropertyDocumentMixin.js b/src/PropertyDocumentMixin.js
index 286f6a7..5decc06 100644
--- a/src/PropertyDocumentMixin.js
+++ b/src/PropertyDocumentMixin.js
@@ -107,6 +107,65 @@ const mxFunction = (base) => {
       this._hasMediaType = false;
     }
 
+    /**
+     * Checks if a union shape represents a nullable type (union with null).
+     * A nullable type is a union of exactly 2 members where one is NilShape
+     * and the other is any type (scalar, array, object, etc.).
+     * 
+     * This is specifically for OpenAPI 3.0 nullable: true which AMF converts
+     * to union of type + null. This simplifies the rendering to "Type or null"
+     * instead of showing a full union selector.
+     * 
+     * @param {any} range AMF range object (should be UnionShape)
+     * @return {Object|undefined} Returns {baseType, isNullable: true} if nullable, undefined otherwise
+     */
+    _checkNullableUnion(range) {
+      if (!range || !this._hasType(range, this.ns.aml.vocabularies.shapes.UnionShape)) {
+        return undefined;
+      }
+      
+      const key = this._getAmfKey(this.ns.aml.vocabularies.shapes.anyOf);
+      const unionMembers = this._ensureArray(range[key]);
+      
+      if (!unionMembers || unionMembers.length !== 2) {
+        return undefined;
+      }
+      
+      // Check if one member is NilShape
+      let nilIndex = -1;
+      let baseTypeIndex = -1;
+      
+      for (let i = 0; i < unionMembers.length; i++) {
+        let member = unionMembers[i];
+        if (Array.isArray(member)) {
+          [member] = member;
+        }
+        member = this._resolve(member);
+        
+        if (this._hasType(member, this.ns.aml.vocabularies.shapes.NilShape)) {
+          nilIndex = i;
+        } else {
+          baseTypeIndex = i;
+        }
+      }
+      
+      // If we found exactly one nil and one non-nil type, it's a nullable
+      if (nilIndex !== -1 && baseTypeIndex !== -1) {
+        let baseType = unionMembers[baseTypeIndex];
+        if (Array.isArray(baseType)) {
+          [baseType] = baseType;
+        }
+        baseType = this._resolve(baseType);
+        
+        return {
+          baseType,
+          isNullable: true
+        };
+      }
+      
+      return undefined;
+    }
+
     /**
      * Computes type from a `http://raml.org/vocabularies/shapes#range` object
      *
@@ -122,6 +181,12 @@ const mxFunction = (base) => {
         return this._computeScalarDataType(range);
       }
       if (this._hasType(range, rs.UnionShape)) {
+        // Check if this is a nullable union (type | null)
+        const nullableCheck = this._checkNullableUnion(range);
+        if (nullableCheck && nullableCheck.isNullable) {
+          const baseTypeName = this._computeRangeDataType(nullableCheck.baseType);
+          return `${baseTypeName} or null`;
+        }
         return 'Union';
       }
       if (this._hasType(range, rs.ArrayShape)) {
@@ -145,9 +210,6 @@ const mxFunction = (base) => {
       if (this._hasType(range, rs.TupleShape)) {
         return 'Tuple';
       }
-      if (this._hasType(range, rs.UnionShape)) {
-        return 'Union';
-      }
       if (this._hasType(range, rs.RecursiveShape)) {
         return 'Recursive';
       }
@@ -313,7 +375,12 @@ const mxFunction = (base) => {
      * @return {Boolean}
      */
     _computeIsUnion(range) {
-      return this._hasType(range, this.ns.aml.vocabularies.shapes.UnionShape);
+      if (!this._hasType(range, this.ns.aml.vocabularies.shapes.UnionShape)) {
+        return false;
+      }
+      // Check if it's a nullable union (which we don't treat as union for UI)
+      const nullableCheck = this._checkNullableUnion(range);
+      return !nullableCheck; // Only true if NOT nullable
     }
 
     /**
@@ -325,7 +392,15 @@ const mxFunction = (base) => {
      * @return {Boolean}
      */
     _computeIsObject(range) {
-      return this._hasType(range, this.ns.w3.shacl.NodeShape);
+      if (this._hasType(range, this.ns.w3.shacl.NodeShape)) {
+        return true;
+      }
+      // Check if it's a nullable object
+      const nullableCheck = this._checkNullableUnion(range);
+      if (nullableCheck) {
+        return this._hasType(nullableCheck.baseType, this.ns.w3.shacl.NodeShape);
+      }
+      return false;
     }
 
     /**
@@ -337,7 +412,15 @@ const mxFunction = (base) => {
      * @return {Boolean}
      */
     _computeIsArray(range) {
-      return this._hasType(range, this.ns.aml.vocabularies.shapes.ArrayShape);
+      if (this._hasType(range, this.ns.aml.vocabularies.shapes.ArrayShape)) {
+        return true;
+      }
+      // Check if it's a nullable array
+      const nullableCheck = this._checkNullableUnion(range);
+      if (nullableCheck) {
+        return this._hasType(nullableCheck.baseType, this.ns.aml.vocabularies.shapes.ArrayShape);
+      }
+      return false;
     }
 
     /**
diff --git a/src/PropertyShapeDocument.js b/src/PropertyShapeDocument.js
index fb46ac0..8b7f0e6 100644
--- a/src/PropertyShapeDocument.js
+++ b/src/PropertyShapeDocument.js
@@ -735,7 +735,14 @@ export class PropertyShapeDocument extends PropertyDocumentMixin(LitElement) {
     if (!this.isComplex || !this.opened || this.isScalarArray) {
       return '';
     }
-    const range = this._resolve(this.range);
+    let range = this._resolve(this.range);
+    
+    // If this is a nullable complex type, extract the base type
+    const nullableCheck = this._checkNullableUnion(range);
+    if (nullableCheck) {
+      range = nullableCheck.baseType;
+    }
+    
     const parentTypeName = this._getParentTypeName();
     return html`<api-type-document
       class="children complex"
diff --git a/test/api-type-document.test.js b/test/api-type-document.test.js
index d278b7c..1ce3699 100644
--- a/test/api-type-document.test.js
+++ b/test/api-type-document.test.js
@@ -893,13 +893,19 @@ describe('<api-type-document>', () => {
           element = await basicFixture();
         });
 
-        it('should render union toggle as "Array of String"', async () => {
+        it('should render nullable array as "Array or null"', async () => {
           const data = await AmfLoader.loadType('test2', compact, 'APIC-631');
           element.amf = data[0];
-          element._typeChanged(element._resolve(data[1]));
-          await nextFrame();
-          const firstToggle = element.shadowRoot.querySelectorAll('.union-toggle')[0]
-          assert.equal(firstToggle.textContent.toLowerCase(), 'array of string');
+          element.type = data[1];
+          await aTimeout(100);
+          // test2 is string[] | nil which should now render as scalar with "Array or null"
+          const shapeDoc = element.shadowRoot.querySelector('property-shape-document');
+          assert.exists(shapeDoc, 'Should have property-shape-document');
+          const dataType = shapeDoc.shadowRoot.querySelector('.data-type');
+          assert.exists(dataType, 'Should have data-type element');
+          // Should show "Array or null" instead of Union selector
+          assert.include(dataType.textContent.toLowerCase(), 'array');
+          assert.include(dataType.textContent.toLowerCase(), 'null');
         });
 
         it('should not render type name as "undefined" for inline type', async () => {
diff --git a/test/nullable-types.test.js b/test/nullable-types.test.js
new file mode 100644
index 0000000..4c59176
--- /dev/null
+++ b/test/nullable-types.test.js
@@ -0,0 +1,218 @@
+import { fixture, assert, nextFrame, aTimeout } from '@open-wc/testing';
+import { AmfLoader } from './amf-loader.js';
+import '../api-type-document.js';
+
+/** @typedef {import('..').ApiTypeDocument} ApiTypeDocument */
+
+describe('Nullable Types Rendering', () => {
+  /**
+   * @param {ApiTypeDocument} element
+   * @param {string} typeName
+   * @param {string} propertyName
+   * @returns {HTMLElement|null}
+   */
+  async function getPropertyElement(element, typeName, propertyName) {
+    const data = await AmfLoader.loadType(typeName, false, 'nullable-test');
+    element.amf = data[0];
+    element.type = data[1];
+    await aTimeout(100);
+    
+    const properties = element.shadowRoot.querySelectorAll('property-shape-document');
+    for (const prop of properties) {
+      const nameEl = prop.shadowRoot.querySelector('.property-name');
+      if (nameEl && nameEl.textContent.trim() === propertyName) {
+        return prop;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * @param {HTMLElement} propertyElement
+   * @returns {string}
+   */
+  function getDataType(propertyElement) {
+    const dataTypeEl = propertyElement.shadowRoot.querySelector('.data-type');
+    return dataTypeEl ? dataTypeEl.textContent.trim() : '';
+  }
+
+  /**
+   * @param {HTMLElement} propertyElement
+   * @returns {boolean}
+   */
+  function hasUnionSelector(propertyElement) {
+    return !!propertyElement.shadowRoot.querySelector('.union-type-selector, .any-of, .one-of');
+  }
+
+  [
+    ['Regular model', false],
+    ['Compact model', true],
+  ].forEach((item) => {
+    describe(String(item[0]), () => {
+      /** @type ApiTypeDocument */
+      let element;
+
+      beforeEach(async () => {
+        element = await fixture(`<api-type-document></api-type-document>`);
+      });
+
+      describe('Scalar Nullables (should show "Type or null")', () => {
+        const scalarTests = [
+          ['nullableString', 'String or null'],
+          ['nullableInteger', 'Integer or null'],
+          ['nullableNumber', 'Number or null'],
+          ['nullableBoolean', 'Boolean or null'],
+          ['nullableDateTime', 'DateTime or null'],
+          ['nullableDate', 'Date or null'],
+          ['nullableEmail', 'String or null'],
+          ['nullableUuid', 'String or null'],
+        ];
+
+        scalarTests.forEach(([propertyName, expectedType]) => {
+          it(`${propertyName} should show "${expectedType}"`, async () => {
+            const prop = await getPropertyElement(element, 'ScalarNullables', propertyName);
+            assert.exists(prop, `Property ${propertyName} should exist`);
+            
+            const dataType = getDataType(prop);
+            assert.equal(dataType, expectedType, `Data type should be ${expectedType}`);
+            
+            const hasSelector = hasUnionSelector(prop);
+            assert.isFalse(hasSelector, 'Should NOT have union selector');
+          });
+        });
+      });
+
+      describe('Complex Nullables (should also show "Type or null")', () => {
+        const complexTests = [
+          ['nullableArray', 'Array or null'],
+          ['nullableObject', 'Object or null'],
+          ['nullableArrayOfObjects', 'Array or null'],
+        ];
+
+        complexTests.forEach(([propertyName, expectedType]) => {
+          it(`${propertyName} should show "${expectedType}"`, async () => {
+            const prop = await getPropertyElement(element, 'ComplexNullables', propertyName);
+            assert.exists(prop, `Property ${propertyName} should exist`);
+            
+            const dataType = getDataType(prop);
+            assert.equal(dataType, expectedType, `Data type should be ${expectedType}`);
+            
+            const hasSelector = hasUnionSelector(prop);
+            assert.isFalse(hasSelector, 'Should NOT have union selector');
+          });
+        });
+      });
+
+      describe('Real Unions (should keep Union selector)', () => {
+        it('stringOrNumber should show Union selector', async () => {
+          const prop = await getPropertyElement(element, 'RealUnions', 'stringOrNumber');
+          assert.exists(prop, 'Property should exist');
+          
+          const dataType = getDataType(prop);
+          // Real unions should not be simplified
+          assert.notInclude(dataType, 'or null', 'Should not show as nullable');
+        });
+
+        it('multipleTypes should show Union selector', async () => {
+          const prop = await getPropertyElement(element, 'RealUnions', 'multipleTypes');
+          assert.exists(prop, 'Property should exist');
+          
+          const dataType = getDataType(prop);
+          assert.notInclude(dataType, 'or null', 'Should not show as nullable');
+        });
+      });
+
+      describe('Nested Nullables', () => {
+        it('nested scalar nullable (email) should show "String or null"', async () => {
+          const data = await AmfLoader.loadType('NestedNullables', false, 'nullable-test');
+          element.amf = data[0];
+          element.type = data[1];
+          await aTimeout(150);
+          
+          // Find the user object property
+          const userProp = Array.from(
+            element.shadowRoot.querySelectorAll('property-shape-document')
+          ).find(p => {
+            const name = p.shadowRoot.querySelector('.property-name');
+            return name && name.textContent.trim() === 'user';
+          });
+          
+          assert.exists(userProp, 'User property should exist');
+          
+          // Expand the user object
+          const toggleBtn = userProp.shadowRoot.querySelector('.complex-toggle');
+          if (toggleBtn) {
+            toggleBtn.click();
+            await aTimeout(100);
+          }
+          
+          // Now check for email inside
+          const apiTypeDoc = userProp.shadowRoot.querySelector('api-type-document');
+          if (apiTypeDoc) {
+            const emailProp = Array.from(
+              apiTypeDoc.shadowRoot.querySelectorAll('property-shape-document')
+            ).find(p => {
+              const name = p.shadowRoot.querySelector('.property-name');
+              return name && name.textContent.trim() === 'email';
+            });
+            
+            if (emailProp) {
+              const dataType = getDataType(emailProp);
+              assert.equal(dataType, 'String or null', 'Nested email should show "String or null"');
+            }
+          }
+        });
+      });
+
+      describe('Edge Cases', () => {
+        const edgeCaseTests = [
+          ['enumNullable', 'String or null'],
+          ['numberWithConstraints', 'Number or null'],
+          ['stringWithPattern', 'String or null'],
+          ['readOnlyNullable', 'String or null'],
+          ['deprecatedNullable', 'Integer or null'],
+        ];
+
+        edgeCaseTests.forEach(([propertyName, expectedType]) => {
+          it(`${propertyName} should show "${expectedType}"`, async () => {
+            const prop = await getPropertyElement(element, 'EdgeCases', propertyName);
+            assert.exists(prop, `Property ${propertyName} should exist`);
+            
+            const dataType = getDataType(prop);
+            assert.equal(dataType, expectedType, `Data type should be ${expectedType}`);
+            
+            const hasSelector = hasUnionSelector(prop);
+            assert.isFalse(hasSelector, 'Should NOT have union selector');
+          });
+        });
+      });
+
+      describe('Request/Response Schemas', () => {
+        it('TestRequest.timezone should show "String or null"', async () => {
+          const prop = await getPropertyElement(element, 'TestRequest', 'timezone');
+          assert.exists(prop, 'Property should exist');
+          
+          const dataType = getDataType(prop);
+          assert.equal(dataType, 'String or null');
+        });
+
+        it('TestResponse.message should show "String or null"', async () => {
+          const prop = await getPropertyElement(element, 'TestResponse', 'message');
+          assert.exists(prop, 'Property should exist');
+          
+          const dataType = getDataType(prop);
+          assert.equal(dataType, 'String or null');
+        });
+
+        it('TestResponse.errorCode should show "Integer or null"', async () => {
+          const prop = await getPropertyElement(element, 'TestResponse', 'errorCode');
+          assert.exists(prop, 'Property should exist');
+          
+          const dataType = getDataType(prop);
+          assert.equal(dataType, 'Integer or null');
+        });
+      });
+    });
+  });
+});
+
diff --git a/test/property-shape-document.test.js b/test/property-shape-document.test.js
index e5087b9..fdf32e4 100644
--- a/test/property-shape-document.test.js
+++ b/test/property-shape-document.test.js
@@ -178,10 +178,11 @@ describe('PropertyShapeDocument', () => {
           assert.isFalse(element.isEnum);
         });
 
-        it('sets isUnion to true when is union', async () => {
+        it('sets isUnion to false when is nullable (not a real union)', async () => {
           const shape = getPropertyShape(element, type, 'nillable');
           element.shape = shape;
-          assert.isTrue(element.isUnion);
+          // nillable is string | nil, which is now treated as nullable, not union
+          assert.isFalse(element.isUnion);
         });
 
         it('sets isUnion to false when is not union', async () => {
@@ -221,10 +222,11 @@ describe('PropertyShapeDocument', () => {
           assert.isTrue(element.isComplex);
         });
 
-        it('sets isComplex to true when is union', async () => {
+        it('sets isComplex to false when is nullable scalar (not complex)', async () => {
           const shape = getPropertyShape(element, type, 'nillable');
           element.shape = shape;
-          assert.isTrue(element.isComplex);
+          // nillable is string | nil, which is now treated as scalar nullable (not complex)
+          assert.isFalse(element.isComplex);
         });
 
         it('sets isComplex to true when array property', async () => {
@@ -308,7 +310,7 @@ describe('PropertyShapeDocument', () => {
           ['fietype', 'File'],
           ['etag', 'String'],
           ['age', 'Integer'],
-          ['nillable', 'Union'],
+          ['nillable', 'String or null'],
           ['birthday', 'Date'],
         ].forEach(([property, dataType]) => {
           it(`sets propertyDataType to ${dataType}`, () => {