diff --git a/scripts/testCodeGen.ts b/scripts/testCodeGen.ts
index 1f9a4e91..e4259717 100644
--- a/scripts/testCodeGen.ts
+++ b/scripts/testCodeGen.ts
@@ -30,6 +30,9 @@ const main = () => {
   Writer.generateTypedefWithTemplateCode("test/argo-rollout/index.json", "test/code/argo-rollout/client.ts", false, {
     sync: false,
   });
+  Writer.generateTypedefWithTemplateCode("test/unknown.schema.domain/index.yml", "test/code/unknown.schema.domain/client.ts", false, {
+    sync: false,
+  });
 
   Writer.generateSplitCode("test/api.test.domain/index.yml", "test/code/split");
 
diff --git a/src/internal/OpenApiTools/ConverterContext.ts b/src/internal/OpenApiTools/ConverterContext.ts
index f3346e53..536b3ad2 100644
--- a/src/internal/OpenApiTools/ConverterContext.ts
+++ b/src/internal/OpenApiTools/ConverterContext.ts
@@ -103,9 +103,12 @@ export const create = (factory: Factory.Type, options?: Options): Types => {
     }
     return text.replace(/-/g, "$").replace(/\//g, "$");
   };
+  const convertOperationId = (text: string): string => {
+    return convertString(text).replace(/\./g, "$");
+  }
   return {
     escapeOperationIdText: (operationId: string): string => {
-      return convertString(operationId);
+      return convertOperationId(operationId);
     },
     escapeDeclarationText: (text: string) => {
       // console.log(`escapeDeclarationText: ${text}` + `-> ${convertReservedWord(convertString(text).replace(/\./g, "$"))}`.padStart(100, " "));
@@ -122,25 +125,25 @@ export const create = (factory: Factory.Type, options?: Options): Types => {
       return convertString(text);
     },
     generateResponseName: (operationId: string, statusCode: string): string => {
-      return Utils.responseName(convertString(operationId), statusCode);
+      return Utils.responseName(convertOperationId(operationId), statusCode);
     },
     generateArgumentParamsTypeDeclaration: (operationId: string) => {
-      return Utils.argumentParamsTypeDeclaration(convertString(operationId));
+      return Utils.argumentParamsTypeDeclaration(convertOperationId(operationId));
     },
     generateRequestContentTypeName: (operationId: string) => {
-      return Utils.requestContentType(convertString(operationId));
+      return Utils.requestContentType(convertOperationId(operationId));
     },
     generateResponseContentTypeName: (operationId: string) => {
-      return Utils.responseContentType(convertString(operationId));
+      return Utils.responseContentType(convertOperationId(operationId));
     },
     generateParameterName: (operationId: string) => {
-      return Utils.parameterName(convertString(operationId));
+      return Utils.parameterName(convertOperationId(operationId));
     },
     generateRequestBodyName: (operationId: string) => {
-      return Utils.requestBodyName(convertString(operationId));
+      return Utils.requestBodyName(convertOperationId(operationId));
     },
     generateFunctionName: (operationId: string) => {
-      return convertString(operationId);
+      return convertOperationId(operationId);
     },
     convertFormatTypeNode: schema => {
       const formatConversions = options?.formatConversions;
diff --git a/src/internal/OpenApiTools/toTypeNode.ts b/src/internal/OpenApiTools/toTypeNode.ts
index 3f3835e8..e0f419ab 100644
--- a/src/internal/OpenApiTools/toTypeNode.ts
+++ b/src/internal/OpenApiTools/toTypeNode.ts
@@ -169,8 +169,12 @@ export const convert: Convert = (
       Logger.info("Parent Schema:");
       Logger.info(JSON.stringify(option.parent));
     }
-    Logger.showFilePosition(entryPoint, currentPoint);
-    throw new UnsetTypeError("Please set 'type' or '$ref' property \n" + JSON.stringify(schema));
+    const typeNode = factory.TypeNode.create({
+      type: "any",
+    });
+    return typeNode;
+    // Logger.showFilePosition(entryPoint, currentPoint);
+    // throw new UnsetTypeError("Please set 'type' or '$ref' property \n" + JSON.stringify(schema));
   }
   switch (schema.type) {
     case "boolean": {
diff --git a/src/utils.ts b/src/utils.ts
index afafdc6a..ac5a74fa 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -9,8 +9,12 @@ export const isAvailableVariableName = (text: string): boolean => {
   return /^[A-Za-z_0-9\s]+$/.test(text);
 };
 
+export const isFirstCharacterIsValidText = (text: string): boolean => {
+  return /^[A-Za-z]+/.test(text);
+}
+
 export const escapeText = (text: string): string => {
-  if (isAvailableVariableName(text)) {
+  if (isAvailableVariableName(text) && isFirstCharacterIsValidText(text)) {
     return text;
   }
   return `"${text}"`;
diff --git a/test/__tests__/__snapshots__/parameter-test.ts.snap b/test/__tests__/__snapshots__/parameter-test.ts.snap
index 63a54130..dbbeb98e 100644
--- a/test/__tests__/__snapshots__/parameter-test.ts.snap
+++ b/test/__tests__/__snapshots__/parameter-test.ts.snap
@@ -229,6 +229,92 @@ exports[`Parameter api.test.domain 1`] = `
       }
     }
   },
+  {
+    \\"operationId\\": \\"i.have.dot\\",
+    \\"convertedParams\\": {
+      \\"escapedOperationId\\": \\"i$have$dot\\",
+      \\"argumentParamsTypeDeclaration\\": \\"Params$i$have$dot\\",
+      \\"functionName\\": \\"i$have$dot\\",
+      \\"requestContentTypeName\\": \\"RequestContentType$i$have$dot\\",
+      \\"responseContentTypeName\\": \\"ResponseContentType$i$have$dot\\",
+      \\"parameterName\\": \\"Parameter$i$have$dot\\",
+      \\"requestBodyName\\": \\"RequestBody$i$have$dot\\",
+      \\"hasRequestBody\\": false,
+      \\"hasParameter\\": false,
+      \\"pickedParameters\\": [],
+      \\"requestContentTypes\\": [],
+      \\"responseSuccessNames\\": [
+        \\"Response$i$have$dot$Status$200\\"
+      ],
+      \\"responseFirstSuccessName\\": \\"Response$i$have$dot$Status$200\\",
+      \\"has2OrMoreSuccessNames\\": false,
+      \\"responseErrorNames\\": [],
+      \\"has2OrMoreRequestContentTypes\\": false,
+      \\"successResponseContentTypes\\": [
+        \\"application/json\\"
+      ],
+      \\"successResponseFirstContentType\\": \\"application/json\\",
+      \\"has2OrMoreSuccessResponseContentTypes\\": false,
+      \\"hasAdditionalHeaders\\": false,
+      \\"hasQueryParameters\\": false
+    },
+    \\"operationParams\\": {
+      \\"httpMethod\\": \\"get\\",
+      \\"requestUri\\": \\"/i/have/dot\\",
+      \\"comment\\": \\"\\",
+      \\"deprecated\\": false,
+      \\"parameters\\": [],
+      \\"responses\\": {
+        \\"200\\": {
+          \\"description\\": \\"Get Books\\",
+          \\"content\\": {
+            \\"application/json\\": {
+              \\"schema\\": {
+                \\"type\\": \\"object\\",
+                \\"properties\\": {
+                  \\"books\\": {
+                    \\"type\\": \\"array\\",
+                    \\"items\\": {
+                      \\"type\\": \\"object\\",
+                      \\"description\\": \\"Item Model\\",
+                      \\"required\\": [
+                        \\"name\\",
+                        \\"children\\"
+                      ],
+                      \\"properties\\": {
+                        \\"name\\": {
+                          \\"type\\": \\"string\\"
+                        },
+                        \\"children\\": {
+                          \\"type\\": \\"array\\",
+                          \\"items\\": {
+                            \\"type\\": \\"object\\",
+                            \\"required\\": [
+                              \\"id\\",
+                              \\"name\\"
+                            ],
+                            \\"properties\\": {
+                              \\"id\\": {
+                                \\"type\\": \\"string\\"
+                              },
+                              \\"name\\": {
+                                \\"type\\": \\"string\\",
+                                \\"description\\": \\"child name\\"
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
   {
     \\"operationId\\": \\"getReferenceItems\\",
     \\"convertedParams\\": {
diff --git a/test/__tests__/__snapshots__/spit-code-test.ts.snap b/test/__tests__/__snapshots__/spit-code-test.ts.snap
index 70bad30f..ad1df96e 100644
--- a/test/__tests__/__snapshots__/spit-code-test.ts.snap
+++ b/test/__tests__/__snapshots__/spit-code-test.ts.snap
@@ -37,6 +37,11 @@ export interface Response$getFullRemoteReference$Status$200 {
         name?: \\"responseA\\";
     };
 }
+export interface Response$i$have$dot$Status$200 {
+    \\"application/json\\": {
+        books?: Schemas.Item[];
+    };
+}
 export interface Response$getReferenceItems$Status$200 {
     \\"application/json\\": {
         books?: Schemas.Item[];
@@ -81,6 +86,7 @@ export type ResponseContentType$getFullRemoteReference = keyof Response$getFullR
 export interface Params$getFullRemoteReference {
     parameter: Parameter$getFullRemoteReference;
 }
+export type ResponseContentType$i$have$dot = keyof Response$i$have$dot$Status$200;
 export type ResponseContentType$getReferenceItems = keyof Response$getReferenceItems$Status$200;
 export type ResponseContentType$searchBook = keyof Response$searchBook$Status$200;
 export interface Params$searchBook {
@@ -106,11 +112,12 @@ export interface QueryParameter {
 export interface QueryParameters {
     [key: string]: QueryParameter;
 }
-export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
+export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$i$have$dot$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
 export namespace ErrorResponse {
     export type getIncludeLocalReference = void;
     export type getIncludeRemoteReference = void;
     export type getFullRemoteReference = void;
+    export type i$have$dot = void;
     export type getReferenceItems = void;
     export type searchBook = void;
     export type getBookById = void;
@@ -164,6 +171,17 @@ export class Client<RequestOption> {
         };
         return this.apiClient.request(\\"GET\\", url, headers, undefined, queryParameters, option);
     }
+    /**
+     * operationId: i.have.dot
+     * Request URI: /i/have/dot
+     */
+    public async i$have$dot(option?: RequestOption): Promise<Response$i$have$dot$Status$200[\\"application/json\\"]> {
+        const url = this.baseUrl + \`/i/have/dot\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
     /**
      * operationId: getReferenceItems
      * Request URI: /get/reference/items
diff --git a/test/__tests__/__snapshots__/template-only-test.ts.snap b/test/__tests__/__snapshots__/template-only-test.ts.snap
index 3818c961..81cfc2ab 100644
--- a/test/__tests__/__snapshots__/template-only-test.ts.snap
+++ b/test/__tests__/__snapshots__/template-only-test.ts.snap
@@ -23,6 +23,7 @@ export type ResponseContentType$getFullRemoteReference = keyof Response$getFullR
 export interface Params$getFullRemoteReference {
     parameter: Parameter$getFullRemoteReference;
 }
+export type ResponseContentType$i$have$dot = keyof Response$i$have$dot$Status$200;
 export type ResponseContentType$getReferenceItems = keyof Response$getReferenceItems$Status$200;
 export type ResponseContentType$searchBook = keyof Response$searchBook$Status$200;
 export interface Params$searchBook {
@@ -48,11 +49,12 @@ export interface QueryParameter {
 export interface QueryParameters {
     [key: string]: QueryParameter;
 }
-export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
+export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$i$have$dot$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
 export namespace ErrorResponse {
     export type getIncludeLocalReference = void;
     export type getIncludeRemoteReference = void;
     export type getFullRemoteReference = void;
+    export type i$have$dot = void;
     export type getReferenceItems = void;
     export type searchBook = void;
     export type getBookById = void;
@@ -94,6 +96,13 @@ export class Client<RequestOption> {
         };
         return this.apiClient.request(\\"GET\\", url, headers, undefined, queryParameters, option);
     }
+    public async i$have$dot(option?: RequestOption): Promise<Response$i$have$dot$Status$200[\\"application/json\\"]> {
+        const url = this.baseUrl + \`/i/have/dot\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
     public async getReferenceItems(option?: RequestOption): Promise<Response$getReferenceItems$Status$200[\\"application/json\\"]> {
         const url = this.baseUrl + \`/get/reference/items\`;
         const headers = {
@@ -152,6 +161,7 @@ export type ResponseContentType$getFullRemoteReference = keyof Response$getFullR
 export interface Params$getFullRemoteReference {
     parameter: Parameter$getFullRemoteReference;
 }
+export type ResponseContentType$i$have$dot = keyof Response$i$have$dot$Status$200;
 export type ResponseContentType$getReferenceItems = keyof Response$getReferenceItems$Status$200;
 export type ResponseContentType$searchBook = keyof Response$searchBook$Status$200;
 export interface Params$searchBook {
@@ -177,11 +187,12 @@ export interface QueryParameter {
 export interface QueryParameters {
     [key: string]: QueryParameter;
 }
-export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
+export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$i$have$dot$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
 export namespace ErrorResponse {
     export type getIncludeLocalReference = void;
     export type getIncludeRemoteReference = void;
     export type getFullRemoteReference = void;
+    export type i$have$dot = void;
     export type getReferenceItems = void;
     export type searchBook = void;
     export type getBookById = void;
@@ -223,6 +234,13 @@ export class Client<RequestOption> {
         };
         return this.apiClient.request(\\"GET\\", url, headers, undefined, queryParameters, option);
     }
+    public i$have$dot(option?: RequestOption): Response$i$have$dot$Status$200[\\"application/json\\"] {
+        const url = this.baseUrl + \`/i/have/dot\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
     public getReferenceItems(option?: RequestOption): Response$getReferenceItems$Status$200[\\"application/json\\"] {
         const url = this.baseUrl + \`/get/reference/items\`;
         const headers = {
diff --git a/test/__tests__/__snapshots__/typedef-with-template-test.ts.snap b/test/__tests__/__snapshots__/typedef-with-template-test.ts.snap
index bc296b60..3d20d7b0 100644
--- a/test/__tests__/__snapshots__/typedef-with-template-test.ts.snap
+++ b/test/__tests__/__snapshots__/typedef-with-template-test.ts.snap
@@ -313,6 +313,11 @@ export interface Response$getFullRemoteReference$Status$200 {
         name?: \\"responseA\\";
     };
 }
+export interface Response$i$have$dot$Status$200 {
+    \\"application/json\\": {
+        books?: Schemas.Item[];
+    };
+}
 export interface Response$getReferenceItems$Status$200 {
     \\"application/json\\": {
         books?: Schemas.Item[];
@@ -357,6 +362,7 @@ export type ResponseContentType$getFullRemoteReference = keyof Response$getFullR
 export interface Params$getFullRemoteReference {
     parameter: Parameter$getFullRemoteReference;
 }
+export type ResponseContentType$i$have$dot = keyof Response$i$have$dot$Status$200;
 export type ResponseContentType$getReferenceItems = keyof Response$getReferenceItems$Status$200;
 export type ResponseContentType$searchBook = keyof Response$searchBook$Status$200;
 export interface Params$searchBook {
@@ -382,11 +388,12 @@ export interface QueryParameter {
 export interface QueryParameters {
     [key: string]: QueryParameter;
 }
-export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
+export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$i$have$dot$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
 export namespace ErrorResponse {
     export type getIncludeLocalReference = void;
     export type getIncludeRemoteReference = void;
     export type getFullRemoteReference = void;
+    export type i$have$dot = void;
     export type getReferenceItems = void;
     export type searchBook = void;
     export type getBookById = void;
@@ -428,6 +435,13 @@ export class Client<RequestOption> {
         };
         return this.apiClient.request(\\"GET\\", url, headers, undefined, queryParameters, option);
     }
+    public async i$have$dot(option?: RequestOption): Promise<Response$i$have$dot$Status$200[\\"application/json\\"]> {
+        const url = this.baseUrl + \`/i/have/dot\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
     public async getReferenceItems(option?: RequestOption): Promise<Response$getReferenceItems$Status$200[\\"application/json\\"]> {
         const url = this.baseUrl + \`/get/reference/items\`;
         const headers = {
@@ -839,6 +853,11 @@ export interface Response$getFullRemoteReference$Status$200 {
         name?: \\"responseA\\";
     };
 }
+export interface Response$i$have$dot$Status$200 {
+    \\"application/json\\": {
+        books?: Schemas.Item[];
+    };
+}
 export interface Response$getReferenceItems$Status$200 {
     \\"application/json\\": {
         books?: Schemas.Item[];
@@ -883,6 +902,7 @@ export type ResponseContentType$getFullRemoteReference = keyof Response$getFullR
 export interface Params$getFullRemoteReference {
     parameter: Parameter$getFullRemoteReference;
 }
+export type ResponseContentType$i$have$dot = keyof Response$i$have$dot$Status$200;
 export type ResponseContentType$getReferenceItems = keyof Response$getReferenceItems$Status$200;
 export type ResponseContentType$searchBook = keyof Response$searchBook$Status$200;
 export interface Params$searchBook {
@@ -908,11 +928,12 @@ export interface QueryParameter {
 export interface QueryParameters {
     [key: string]: QueryParameter;
 }
-export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
+export type SuccessResponses = Response$getIncludeLocalReference$Status$200 | Response$getFullRemoteReference$Status$200 | Response$i$have$dot$Status$200 | Response$getReferenceItems$Status$200 | Response$searchBook$Status$200 | Response$getBookById$Status$200 | Response$deleteBook$Status$200;
 export namespace ErrorResponse {
     export type getIncludeLocalReference = void;
     export type getIncludeRemoteReference = void;
     export type getFullRemoteReference = void;
+    export type i$have$dot = void;
     export type getReferenceItems = void;
     export type searchBook = void;
     export type getBookById = void;
@@ -954,6 +975,13 @@ export class Client<RequestOption> {
         };
         return this.apiClient.request(\\"GET\\", url, headers, undefined, queryParameters, option);
     }
+    public i$have$dot(option?: RequestOption): Response$i$have$dot$Status$200[\\"application/json\\"] {
+        const url = this.baseUrl + \`/i/have/dot\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
     public getReferenceItems(option?: RequestOption): Response$getReferenceItems$Status$200[\\"application/json\\"] {
         const url = this.baseUrl + \`/get/reference/items\`;
         const headers = {
diff --git a/test/__tests__/__snapshots__/unknown-schema-domain-test.ts.snap b/test/__tests__/__snapshots__/unknown-schema-domain-test.ts.snap
new file mode 100644
index 00000000..79af3182
--- /dev/null
+++ b/test/__tests__/__snapshots__/unknown-schema-domain-test.ts.snap
@@ -0,0 +1,59 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Unknown client.ts 1`] = `
+"// 
+// Generated by @himenon/openapi-typescript-code-generator
+// 
+// OpenApi : 3.1.0
+// 
+// License  : MIT
+// 
+
+
+export namespace Schemas {
+    /** What is this? */
+    export type Unknown = any;
+}
+export interface Parameter$getUnknown {
+    /** Number Book ID */
+    id: number;
+}
+export interface Response$getUnknown$Status$200 {
+    \\"application/json\\": Schemas.Unknown;
+}
+export type ResponseContentType$getUnknown = keyof Response$getUnknown$Status$200;
+export interface Params$getUnknown {
+    parameter: Parameter$getUnknown;
+}
+export type HttpMethod = \\"GET\\" | \\"PUT\\" | \\"POST\\" | \\"DELETE\\" | \\"OPTIONS\\" | \\"HEAD\\" | \\"PATCH\\" | \\"TRACE\\";
+export interface ObjectLike {
+    [key: string]: any;
+}
+export interface QueryParameter {
+    value: any;
+    style?: \\"form\\" | \\"spaceDelimited\\" | \\"pipeDelimited\\" | \\"deepObject\\";
+    explode: boolean;
+}
+export interface QueryParameters {
+    [key: string]: QueryParameter;
+}
+export type SuccessResponses = Response$getUnknown$Status$200;
+export namespace ErrorResponse {
+    export type getUnknown = void;
+}
+export interface ApiClient<RequestOption> {
+    request: <T = SuccessResponses>(httpMethod: HttpMethod, url: string, headers: ObjectLike | any, requestBody: ObjectLike | any, queryParameters: QueryParameters | undefined, options?: RequestOption) => Promise<T>;
+}
+export class Client<RequestOption> {
+    private baseUrl: string;
+    constructor(private apiClient: ApiClient<RequestOption>, baseUrl: string) { this.baseUrl = baseUrl.replace(/\\\\/$/, \\"\\"); }
+    public async getUnknown(params: Params$getUnknown, option?: RequestOption): Promise<Response$getUnknown$Status$200[\\"application/json\\"]> {
+        const url = this.baseUrl + \`/get/unknown\`;
+        const headers = {
+            Accept: \\"application/json\\"
+        };
+        return this.apiClient.request(\\"GET\\", url, headers, undefined, undefined, option);
+    }
+}
+"
+`;
diff --git a/test/__tests__/unknown-schema-domain-test.ts b/test/__tests__/unknown-schema-domain-test.ts
new file mode 100644
index 00000000..c847cd24
--- /dev/null
+++ b/test/__tests__/unknown-schema-domain-test.ts
@@ -0,0 +1,12 @@
+import * as fs from "fs";
+import * as path from "path";
+
+import * as Utils from "../utils";
+
+describe("Unknown", () => {
+  test("client.ts", () => {
+    const generateCode = fs.readFileSync(path.join(__dirname, "../code/unknown.schema.domain/client.ts"), { encoding: "utf-8" });
+    const text = Utils.replaceVersionInfo(generateCode);
+    expect(text).toMatchSnapshot();
+  });
+});
diff --git a/test/api.test.domain/index.yml b/test/api.test.domain/index.yml
index 194762d7..df504206 100644
--- a/test/api.test.domain/index.yml
+++ b/test/api.test.domain/index.yml
@@ -365,6 +365,21 @@ paths:
     $ref: "#/components/pathItems/IncludeRemoteReference"
   /FullRemoteReference:
     $ref: "./components/pathItems/FullRemoteReference.yml"
+  /i/have/dot:
+    get:
+      operationId: i.have.dot
+      responses:
+        200:
+          description: Get Books
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  books:
+                    type: array
+                    items:
+                      $ref: "./components/schemas/Item.yml"
   /get/reference/items:
     get:
       operationId: getReferenceItems
diff --git a/test/unknown.schema.domain/index.yml b/test/unknown.schema.domain/index.yml
new file mode 100644
index 00000000..0e99d325
--- /dev/null
+++ b/test/unknown.schema.domain/index.yml
@@ -0,0 +1,41 @@
+openapi: 3.1.0
+info:
+  version: 1.0.0
+  title: api.test.domain
+  description: Library test schema
+  license:
+    name: MIT
+
+servers:
+  - url: "http://dev.unknown.schema.domain/"
+    description: Development Environment
+  - url: "https://unknown.schema.domain/"
+    description: Production Environment
+
+tags:
+  - name: test
+
+components:
+  schemas:
+    Unknown:
+      description: "What is this?"
+
+paths:
+  /get/unknown:
+    get:
+      operationId: getUnknown
+      parameters:
+        - name: id
+          in: path
+          required: true
+          description: Number Book ID
+          schema:
+            type: number
+            format: uuid
+      responses:
+        200:
+          description: "get books"
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Unknown"
\ No newline at end of file