diff --git a/packages/global/core/workflow/runtime/utils.ts b/packages/global/core/workflow/runtime/utils.ts
index 8fef7e728..a226ff7f1 100644
--- a/packages/global/core/workflow/runtime/utils.ts
+++ b/packages/global/core/workflow/runtime/utils.ts
@@ -67,25 +67,8 @@ export const valueTypeFormat = (value: any, valueType?: WorkflowIOValueTypeEnum)
   };
 
   // Handle null/undefined, return default value by type
-  if (value === undefined || value === null) {
-    if (!valueType || valueType === WorkflowIOValueTypeEnum.any) return value;
-
-    // Default value map (use function to ensure new reference each time)
-    const defaultValueMap: Partial<Record<WorkflowIOValueTypeEnum, () => any>> = {
-      [WorkflowIOValueTypeEnum.string]: () => '',
-      [WorkflowIOValueTypeEnum.number]: () => 0,
-      [WorkflowIOValueTypeEnum.boolean]: () => false,
-      [WorkflowIOValueTypeEnum.arrayString]: () => [],
-      [WorkflowIOValueTypeEnum.arrayNumber]: () => [],
-      [WorkflowIOValueTypeEnum.arrayBoolean]: () => [],
-      [WorkflowIOValueTypeEnum.arrayObject]: () => [],
-      [WorkflowIOValueTypeEnum.arrayAny]: () => [],
-      [WorkflowIOValueTypeEnum.object]: () => ({})
-    };
-
-    const getDefaultValue = defaultValueMap[valueType];
-    return getDefaultValue ? getDefaultValue() : value;
-  }
+  if (value === undefined || value === null) return value;
+  if (!valueType || valueType === WorkflowIOValueTypeEnum.any) return value;
 
   // Password check
   if (valueType === WorkflowIOValueTypeEnum.string && isSecretValue(value)) return value;
diff --git a/packages/service/core/ai/llm/request.ts b/packages/service/core/ai/llm/request.ts
index e8983aba5..d9b317a5e 100644
--- a/packages/service/core/ai/llm/request.ts
+++ b/packages/service/core/ai/llm/request.ts
@@ -537,7 +537,7 @@ const llmCompletionsBodyFormat = async <T extends CompletionsBodyType>({
         : undefined,
     ...modelData?.defaultConfig,
     response_format,
-    stop: stop?.split('|'),
+    stop: stop?.split('|').filter((item) => !!item.trim()),
     ...(toolCallMode === 'toolChoice' && {
       tools,
       tool_choice,
diff --git a/packages/service/core/ai/utils.ts b/packages/service/core/ai/utils.ts
index 83287ddc0..5df84546c 100644
--- a/packages/service/core/ai/utils.ts
+++ b/packages/service/core/ai/utils.ts
@@ -20,7 +20,7 @@ export const computedMaxToken = ({
   if (maxToken === undefined) return;
 
   maxToken = Math.min(maxToken, model.maxResponse);
-  return Math.max(maxToken, min || 0);
+  return Math.max(maxToken, min || 1);
 };
 
 // FastGPT temperature range: [0,10], ai temperature:[0,2],{0,1]……
diff --git a/packages/service/core/workflow/dispatch/tools/http468.ts b/packages/service/core/workflow/dispatch/tools/http468.ts
index a92918a2f..d39c4844a 100644
--- a/packages/service/core/workflow/dispatch/tools/http468.ts
+++ b/packages/service/core/workflow/dispatch/tools/http468.ts
@@ -62,14 +62,13 @@ const UNDEFINED_SIGN = 'UNDEFINED_SIGN';
 
 export const dispatchHttp468Request = async (props: HttpRequestProps): Promise<HttpResponse> => {
   let {
-    runningAppInfo: { id: appId, teamId, tmbId },
+    runningAppInfo: { id: appId },
     chatId,
     responseChatItemId,
     variables,
     node,
     runtimeNodes,
     histories,
-    workflowStreamResponse,
     params: {
       system_httpMethod: httpMethod = 'POST',
       system_httpReqUrl: httpReqUrl,
@@ -332,8 +331,10 @@ export const replaceJsonBodyString = (
   };
 
   const valToStr = (val: any, isQuoted = false) => {
-    if (val === undefined) return 'null';
-    if (val === null) return 'null';
+    if (val === undefined || val === null) {
+      if (isQuoted) return '';
+      return 'null';
+    }
 
     if (typeof val === 'object') {
       const jsonStr = JSON.stringify(val);
diff --git a/test/cases/service/core/app/workflow/dispatch/http.test.ts b/test/cases/service/core/app/workflow/dispatch/http.test.ts
index c92e2fc94..76b2ddf1b 100644
--- a/test/cases/service/core/app/workflow/dispatch/http.test.ts
+++ b/test/cases/service/core/app/workflow/dispatch/http.test.ts
@@ -19,6 +19,8 @@ describe('replaceJsonBodyString', () => {
   ] as unknown as RuntimeNodeItemType[];
 
   const mockVariables = {
+    undefinedVar: undefined,
+    nullVar: null,
     userName: 'John Doe',
     userAge: 30,
     isActive: true,
@@ -43,6 +45,14 @@ describe('replaceJsonBodyString', () => {
   };
 
   describe('Basic variable replacement functionality', () => {
+    it('字符串为空', () => {
+      const input = '{"name": "{{undefinedVar}}"}';
+      const expected = '{"name": ""}';
+
+      const result = replaceJsonBodyString({ text: input }, mockProps);
+      expect(result).toBe(expected);
+    });
+
     it('should correctly replace string variables', () => {
       const input = '{"name": "{{userName}}", "greeting": "Hello {{userName}}"}';
       const expected = '{"name": "John Doe", "greeting": "Hello John Doe"}';
@@ -241,7 +251,7 @@ describe('replaceJsonBodyString', () => {
 
     it('should handle non-existent variables', () => {
       const input = '{"missing": "{{nonExistentVar}}", "static": "value"}';
-      const expected = '{"missing": "null", "static": "value"}';
+      const expected = '{"missing": "", "static": "value"}';
 
       const result = replaceJsonBodyString({ text: input }, mockProps);
       expect(result).toBe(expected);
@@ -626,7 +636,7 @@ describe('replaceJsonBodyString', () => {
 
       // Verify no code execution occurred (template injection variable was replaced with null because it doesn't exist)
       expect(typeof parsed.templateTests.inject).toBe('string');
-      expect(parsed.templateTests.inject).toBe('null'); // Non-existent variables become "null"
+      expect(parsed.templateTests.inject).toBe(''); // Non-existent variables become "null"
     });
   });
 });
diff --git a/test/cases/service/core/app/workflow/dispatch/utils.test.ts b/test/cases/service/core/app/workflow/dispatch/utils.test.ts
index 66e6ccb96..100fa4008 100644
--- a/test/cases/service/core/app/workflow/dispatch/utils.test.ts
+++ b/test/cases/service/core/app/workflow/dispatch/utils.test.ts
@@ -311,109 +311,3 @@ describe('valueTypeFormat', () => {
   //   });
   // });
 });
-
-import { getHistories } from '@fastgpt/service/core/workflow/dispatch/utils';
-import { ChatItemValueTypeEnum, ChatRoleEnum } from '@fastgpt/global/core/chat/constants';
-import type { ChatItemType } from '@fastgpt/global/core/chat/type';
-
-describe('getHistories test', async () => {
-  const MockHistories: ChatItemType[] = [
-    {
-      obj: ChatRoleEnum.System,
-      value: [
-        {
-          type: ChatItemValueTypeEnum.text,
-          text: {
-            content: '你好'
-          }
-        }
-      ]
-    },
-    {
-      obj: ChatRoleEnum.Human,
-      value: [
-        {
-          type: ChatItemValueTypeEnum.text,
-          text: {
-            content: '你好'
-          }
-        }
-      ]
-    },
-    {
-      obj: ChatRoleEnum.AI,
-      value: [
-        {
-          type: ChatItemValueTypeEnum.text,
-          text: {
-            content: '你好2'
-          }
-        }
-      ]
-    },
-    {
-      obj: ChatRoleEnum.Human,
-      value: [
-        {
-          type: ChatItemValueTypeEnum.text,
-          text: {
-            content: '你好3'
-          }
-        }
-      ]
-    },
-    {
-      obj: ChatRoleEnum.AI,
-      value: [
-        {
-          type: ChatItemValueTypeEnum.text,
-          text: {
-            content: '你好4'
-          }
-        }
-      ]
-    }
-  ];
-
-  it('getHistories', async () => {
-    // Number
-    expect(getHistories(1, MockHistories)).toEqual([
-      ...MockHistories.slice(0, 1),
-      ...MockHistories.slice(-2)
-    ]);
-    expect(getHistories(2, MockHistories)).toEqual([...MockHistories.slice(0)]);
-    expect(getHistories(4, MockHistories)).toEqual([...MockHistories.slice(0)]);
-
-    // Array
-    expect(
-      getHistories(
-        [
-          {
-            obj: ChatRoleEnum.Human,
-            value: [
-              {
-                type: ChatItemValueTypeEnum.text,
-                text: {
-                  content: '你好'
-                }
-              }
-            ]
-          }
-        ],
-        MockHistories
-      )
-    ).toEqual([
-      {
-        obj: ChatRoleEnum.Human,
-        value: [
-          {
-            type: ChatItemValueTypeEnum.text,
-            text: {
-              content: '你好'
-            }
-          }
-        ]
-      }
-    ]);
-  });
-});