fix(mock-server): improve mock response name validation

packages/bruno-app/src/components/MockServer/CloneMockServerModal/index.js

@@ -54,7 +54,6 @@ const CloneMockServerModal = ({
       port: Yup.number()
         .min(1, 'Port must be at least 1')
         .max(65535, 'Port must be 65535 or less')
-        .required('Port is required')
         .test('duplicate-port', 'This port is already used by another mock server', (value) => (
           !isMockServerPortTaken(configuredInstances, value)
         ))

packages/bruno-app/src/components/MockServer/CreateMockServerModal/index.js

@@ -211,8 +211,7 @@ const CreateMockServerModal = ({
       }),
       port: Yup.number()
         .min(1, 'Port must be at least 1')
-        .max(65535, 'Port must be 65535 or less')
-        .required('Port is required'),
+        .max(65535, 'Port must be 65535 or less'),
       globalDelay: Yup.number().min(0, 'Delay cannot be negative')
     }, [['sourceType', 'linkSource']]),
     onSubmit: async (values) => {
@@ -329,6 +328,12 @@ const CreateMockServerModal = ({
     formik.handleSubmit();
   };
 
+  const handleCancel = () => {
+    formik.resetForm({ values: formik.values });
+    setPortError(null);
+    onClose();
+  };
+
   const handleDelete = () => {
     if (editingInstance && onDelete) {
       onDelete(editingInstance);
@@ -342,7 +347,7 @@ const CreateMockServerModal = ({
         title={isEditing ? 'Mock Server Settings' : 'Create Mock Server'}
         confirmText={isEditing ? 'Save' : 'Create'}
         handleConfirm={handleConfirm}
-        handleCancel={onClose}
+        handleCancel={handleCancel}
         footerLeft={isEditing && onDelete ? (
           <Button
             type="button"

packages/bruno-app/src/components/MockServer/MockResponse/CreateMockResponseModal/index.js

@@ -2,7 +2,12 @@ import React, { useEffect, useMemo, useRef, useState } from 'react';
 import Portal from 'components/Portal';
 import Modal from 'components/Modal';
 import statusCodePhraseMap from 'components/ResponsePane/StatusCode/get-status-code-phrase';
-import { collectCollectionExamples } from 'utils/mock-server/mock-responses';
+import {
+  collectCollectionExamples,
+  getMockResponseNameError,
+  isMockResponseNameTaken,
+  MOCK_RESPONSE_NAME_MAX_LENGTH
+} from 'utils/mock-server/mock-responses';
 
 const BODY_TYPES = [
   { value: 'json', label: 'JSON' },
@@ -13,7 +18,7 @@ const BODY_TYPES = [
 
 const DESCRIPTION_MAX_LENGTH = 1000;
 
-const CreateMockResponseModal = ({ collection, onCreate, onClose }) => {
+const CreateMockResponseModal = ({ collection, existingResponses = [], onCreate, onClose }) => {
   const nameInputRef = useRef();
   const [name, setName] = useState('');
   const [description, setDescription] = useState('');
@@ -50,8 +55,16 @@ const CreateMockResponseModal = ({ collection, onCreate, onClose }) => {
   }, []);
 
   const handleConfirm = async () => {
-    if (!nameValue.trim()) {
-      setNameError('Mock response name is required');
+    const trimmedName = nameValue.trim();
+
+    const validationError = getMockResponseNameError(trimmedName);
+    if (validationError) {
+      setNameError(validationError);
+      return;
+    }
+
+    if (isMockResponseNameTaken(existingResponses, trimmedName)) {
+      setNameError('A mock response with this name already exists');
       return;
     }
 
@@ -63,7 +76,7 @@ const CreateMockResponseModal = ({ collection, onCreate, onClose }) => {
     setIsSaving(true);
     try {
       await onCreate({
-        name: nameValue.trim(),
+        name: trimmedName,
         description: description.trim(),
         statusCode: Number(statusValue) || 200,
         bodyType: bodyTypeValue,
@@ -104,6 +117,7 @@ const CreateMockResponseModal = ({ collection, onCreate, onClose }) => {
               autoCorrect="off"
               autoCapitalize="off"
               spellCheck="false"
+              maxLength={MOCK_RESPONSE_NAME_MAX_LENGTH}
               value={nameValue}
               onChange={(event) => {
                 setName(event.target.value);

packages/bruno-app/src/components/MockServer/MockResponse/MockResponsesList/index.js

@@ -354,6 +354,7 @@ const MockResponsesList = ({ instance, collection }) => {
       {showCreateModal ? (
         <CreateMockResponseModal
           collection={isSpecServer ? null : resolvedCollection}
+          existingResponses={responses}
           onCreate={handleCreate}
           onClose={() => setShowCreateModal(false)}
         />

packages/bruno-app/src/components/MockServer/MockResponse/RenameMockResponseModal/index.js

@@ -1,15 +1,22 @@
 import { useEffect, useRef, useState } from 'react';
 import Portal from 'components/Portal';
 import Modal from 'components/Modal';
+import {
+  getMockResponseNameError,
+  isMockResponseNameTaken,
+  MOCK_RESPONSE_NAME_MAX_LENGTH
+} from 'utils/mock-server/mock-responses';
 
 const RenameMockResponseModal = ({
   response,
+  existingResponses = [],
   onClose,
   onConfirm,
   isSaving = false
 }) => {
   const inputRef = useRef();
   const [name, setName] = useState(response?.name || '');
+  const [nameError, setNameError] = useState('');
 
   useEffect(() => {
     if (inputRef.current) {
@@ -20,7 +27,15 @@ const RenameMockResponseModal = ({
 
   const handleConfirm = () => {
     const trimmedName = name.trim();
-    if (!trimmedName) {
+
+    const validationError = getMockResponseNameError(trimmedName);
+    if (validationError) {
+      setNameError(validationError);
+      return;
+    }
+
+    if (isMockResponseNameTaken(existingResponses, trimmedName, response?.uid)) {
+      setNameError('A mock response with this name already exists');
       return;
     }
 
@@ -48,10 +63,19 @@ const RenameMockResponseModal = ({
             ref={inputRef}
             type="text"
             className="textbox mt-2 w-full"
+            maxLength={MOCK_RESPONSE_NAME_MAX_LENGTH}
             value={name}
-            onChange={(event) => setName(event.target.value)}
+            onChange={(event) => {
+              setName(event.target.value);
+              if (nameError) {
+                setNameError('');
+              }
+            }}
             data-testid="mock-response-rename-name-input"
           />
+          {nameError ? (
+            <div className="text-red-500 mt-1">{nameError}</div>
+          ) : null}
         </div>
       </Modal>
     </Portal>

packages/bruno-app/src/components/MockServer/RenameMockServerModal/index.js

@@ -66,14 +66,19 @@ const RenameMockServerModal = ({ instance, onClose }) => {
     }
   }, []);
 
+  const handleCancel = () => {
+    formik.resetForm({ values: formik.values });
+    onClose();
+  };
+
   return (
     <Portal>
       <Modal
         size="md"
         title="Rename Mock Server"
         confirmText="Rename"
         handleConfirm={() => formik.handleSubmit()}
-        handleCancel={onClose}
+        handleCancel={handleCancel}
         dataTestId="mock-server-rename-modal"
       >
         <form className="bruno-form" onSubmit={(event) => event.preventDefault()}>

packages/bruno-app/src/components/MockServer/Sidebar/MockServers/MockResponseSidebarItem/index.js

@@ -20,6 +20,7 @@ const MockResponseSidebarItem = ({
 }) => {
   const dispatch = useDispatch();
   const activeTabUid = useSelector((state) => state.tabs?.activeTabUid);
+  const existingResponses = useSelector((state) => state.mockServer.mockResponses[instance.uid] || []);
   const [showRenameModal, setShowRenameModal] = useState(false);
   const [showDeleteModal, setShowDeleteModal] = useState(false);
   const [isRenaming, setIsRenaming] = useState(false);
@@ -142,6 +143,7 @@ const MockResponseSidebarItem = ({
       {showRenameModal ? (
         <RenameMockResponseModal
           response={response}
+          existingResponses={existingResponses}
           isSaving={isRenaming}
           onClose={() => {
             if (!isRenaming) {

packages/bruno-app/src/utils/mock-server/mock-responses.js

@@ -226,6 +226,33 @@ export const resolveMockResponseEditorCollection = ({
   return enrichedCollection;
 };
 
+export const MOCK_RESPONSE_NAME_MAX_LENGTH = 255;
+
+export const getMockResponseNameError = (name) => {
+  const value = name == null ? '' : String(name).trim();
+
+  if (!value) {
+    return 'Mock response name is required';
+  }
+
+  if (value.length > MOCK_RESPONSE_NAME_MAX_LENGTH) {
+    return `Name must be ${MOCK_RESPONSE_NAME_MAX_LENGTH} characters or less`;
+  }
+
+  return null;
+};
+
+export const isMockResponseNameTaken = (responses = [], name, excludeUid = null) => {
+  const normalized = name?.trim().toLowerCase();
+  if (!normalized) {
+    return false;
+  }
+
+  return responses.some((response) => (
+    response.uid !== excludeUid && response.name?.trim().toLowerCase() === normalized
+  ));
+};
+
 export const cloneMockResponseRecord = (response, { name } = {}) => {
   const cloned = JSON.parse(JSON.stringify(response));
   cloned.uid = uuid();

packages/bruno-app/src/utils/mock-server/mock-responses.spec.js

@@ -9,7 +9,14 @@ jest.mock('utils/common', () => {
   };
 });
 
-import { cloneMockResponseRecord, resolveMockResponseCollection, resolveMockResponseEditorCollection } from './mock-responses';
+import {
+  cloneMockResponseRecord,
+  getMockResponseNameError,
+  isMockResponseNameTaken,
+  MOCK_RESPONSE_NAME_MAX_LENGTH,
+  resolveMockResponseCollection,
+  resolveMockResponseEditorCollection
+} from './mock-responses';
 
 describe('mock-responses', () => {
   it('clones mock responses with new uids and a copy name', () => {
@@ -108,4 +115,63 @@ describe('resolveMockResponseEditorCollection', () => {
     expect(enriched.workspaceProcessEnvVariables).toEqual({ NODE_ENV: 'test' });
     expect(enriched.environments[0].variables[0].value).toBe('https://api.example.com');
   });
+
+  describe('getMockResponseNameError', () => {
+    it('flags empty and whitespace-only names', () => {
+      expect(getMockResponseNameError('')).toBe('Mock response name is required');
+      expect(getMockResponseNameError('   ')).toBe('Mock response name is required');
+      expect(getMockResponseNameError(null)).toBe('Mock response name is required');
+      expect(getMockResponseNameError(undefined)).toBe('Mock response name is required');
+    });
+
+    it('flags names longer than the max length after trimming', () => {
+      const overflow = 'a'.repeat(MOCK_RESPONSE_NAME_MAX_LENGTH + 1);
+      expect(getMockResponseNameError(overflow))
+        .toBe(`Name must be ${MOCK_RESPONSE_NAME_MAX_LENGTH} characters or less`);
+    });
+
+    it('accepts names within bounds', () => {
+      expect(getMockResponseNameError('Order 200')).toBeNull();
+      expect(getMockResponseNameError('a'.repeat(MOCK_RESPONSE_NAME_MAX_LENGTH))).toBeNull();
+      // trailing spaces are ignored — they get trimmed on save
+      expect(getMockResponseNameError('Order 200   ')).toBeNull();
+    });
+
+    it('measures the trimmed length, not the raw length', () => {
+      const paddedAtLimit = `   ${'a'.repeat(MOCK_RESPONSE_NAME_MAX_LENGTH)}   `;
+      const paddedOverLimit = `   ${'a'.repeat(MOCK_RESPONSE_NAME_MAX_LENGTH + 1)}   `;
+      expect(getMockResponseNameError(paddedAtLimit)).toBeNull();
+      expect(getMockResponseNameError(paddedOverLimit))
+        .toBe(`Name must be ${MOCK_RESPONSE_NAME_MAX_LENGTH} characters or less`);
+    });
+  });
+
+  describe('isMockResponseNameTaken', () => {
+    const responses = [
+      { uid: 'r-1', name: 'Success' },
+      { uid: 'r-2', name: '  Not Found  ' }
+    ];
+
+    it('detects duplicates case-insensitively and ignores surrounding whitespace', () => {
+      expect(isMockResponseNameTaken(responses, 'success')).toBe(true);
+      expect(isMockResponseNameTaken(responses, 'SUCCESS')).toBe(true);
+      expect(isMockResponseNameTaken(responses, '  Success  ')).toBe(true);
+      expect(isMockResponseNameTaken(responses, 'not found')).toBe(true);
+    });
+
+    it('excludes the record being renamed', () => {
+      expect(isMockResponseNameTaken(responses, 'success', 'r-1')).toBe(false);
+    });
+
+    it('returns false for empty or missing names', () => {
+      expect(isMockResponseNameTaken(responses, '')).toBe(false);
+      expect(isMockResponseNameTaken(responses, '   ')).toBe(false);
+      expect(isMockResponseNameTaken(responses, null)).toBe(false);
+    });
+
+    it('handles an empty response list', () => {
+      expect(isMockResponseNameTaken([], 'anything')).toBe(false);
+      expect(isMockResponseNameTaken(undefined, 'anything')).toBe(false);
+    });
+  });
 });

packages/bruno-electron/src/app/mock-server/mock-response-store.js

@@ -412,6 +412,17 @@ const saveMockResponse = (location, response) => {
   };
 
   const responses = [...getMockServerResponses(location)];
+
+  const normalizedName = nextResponse.name?.trim().toLowerCase();
+  if (normalizedName) {
+    const isDuplicate = responses.some((item) => (
+      item.uid !== nextResponse.uid && item.name?.trim().toLowerCase() === normalizedName
+    ));
+    if (isDuplicate) {
+      throw new Error('A mock response with this name already exists');
+    }
+  }
+
   const index = responses.findIndex((item) => item.uid === nextResponse.uid);
 
   if (index >= 0) {

packages/bruno-electron/tests/mock-response-store.test.js

@@ -85,6 +85,41 @@ describe('mock-response-store', () => {
     expect(store.mockServers['mock-2'].responses).toHaveLength(1);
   });
 
+  it('rejects a duplicate mock response name on the same server (case- and whitespace-insensitive)', () => {
+    const location = {
+      mockServerUid: 'mock-1',
+      sourceType: 'spec',
+      workspacePath
+    };
+
+    saveMockResponse(location, {
+      uid: 'response-1',
+      name: 'Users',
+      request: { url: '/users', method: 'GET' },
+      response: { status: 200, body: { type: 'json', content: '{}' } },
+      rules: { operator: 'AND', conditions: [] }
+    });
+
+    expect(() => saveMockResponse(location, {
+      uid: 'response-2',
+      name: '  users  ',
+      request: { url: '/users', method: 'GET' },
+      response: { status: 200, body: { type: 'json', content: '{}' } },
+      rules: { operator: 'AND', conditions: [] }
+    })).toThrow('A mock response with this name already exists');
+
+    // Same uid, same name is a legitimate update — must not throw
+    expect(() => saveMockResponse(location, {
+      uid: 'response-1',
+      name: 'Users',
+      request: { url: '/users', method: 'POST' },
+      response: { status: 201, body: { type: 'json', content: '{}' } },
+      rules: { operator: 'AND', conditions: [] }
+    })).not.toThrow();
+
+    expect(listMockResponses(location)).toHaveLength(1);
+  });
+
   it('removes a mock server block from workspace mockserver.yml on delete', () => {
     const location = {
       mockServerUid: 'mock-1',