diff --git a/apps/server/src/services/llm/config/configuration_helpers.spec.ts b/apps/server/src/services/llm/config/configuration_helpers.spec.ts
index 422773202..82d912301 100644
--- a/apps/server/src/services/llm/config/configuration_helpers.spec.ts
+++ b/apps/server/src/services/llm/config/configuration_helpers.spec.ts
@@ -94,6 +94,83 @@ describe('configuration_helpers', () => {
                 fullIdentifier: ''
             });
         });
+
+        // Tests for special characters in model names
+        it('should handle model names with periods', () => {
+            const result = configHelpers.parseModelIdentifier('gpt-4.1-turbo-preview');
+            
+            expect(result).toStrictEqual({
+                modelId: 'gpt-4.1-turbo-preview',
+                fullIdentifier: 'gpt-4.1-turbo-preview'
+            });
+        });
+
+        it('should handle model names with provider prefix and periods', () => {
+            const result = configHelpers.parseModelIdentifier('openai:gpt-4.1-turbo');
+            
+            expect(result).toStrictEqual({
+                provider: 'openai',
+                modelId: 'gpt-4.1-turbo',
+                fullIdentifier: 'openai:gpt-4.1-turbo'
+            });
+        });
+
+        it('should handle model names with multiple colons', () => {
+            const result = configHelpers.parseModelIdentifier('custom:model:v1.2:latest');
+            
+            expect(result).toStrictEqual({
+                modelId: 'custom:model:v1.2:latest',
+                fullIdentifier: 'custom:model:v1.2:latest'
+            });
+        });
+
+        it('should handle Ollama model names with colons', () => {
+            const result = configHelpers.parseModelIdentifier('ollama:llama3.1:70b-instruct-q4_K_M');
+            
+            expect(result).toStrictEqual({
+                provider: 'ollama',
+                modelId: 'llama3.1:70b-instruct-q4_K_M',
+                fullIdentifier: 'ollama:llama3.1:70b-instruct-q4_K_M'
+            });
+        });
+
+        it('should handle model names with slashes', () => {
+            const result = configHelpers.parseModelIdentifier('library/mistral:7b-instruct');
+            
+            expect(result).toStrictEqual({
+                modelId: 'library/mistral:7b-instruct',
+                fullIdentifier: 'library/mistral:7b-instruct'
+            });
+        });
+
+        it('should handle complex model names with special characters', () => {
+            const complexName = 'org/model-v1.2.3:tag@version#variant';
+            const result = configHelpers.parseModelIdentifier(complexName);
+            
+            expect(result).toStrictEqual({
+                modelId: complexName,
+                fullIdentifier: complexName
+            });
+        });
+
+        it('should handle model names with @ symbols', () => {
+            const result = configHelpers.parseModelIdentifier('claude-3.5-sonnet@20241022');
+            
+            expect(result).toStrictEqual({
+                modelId: 'claude-3.5-sonnet@20241022',
+                fullIdentifier: 'claude-3.5-sonnet@20241022'
+            });
+        });
+
+        it('should not modify or encode special characters', () => {
+            const specialChars = 'model!@#$%^&*()_+-=[]{}|;:\'",.<>?/~`';
+            const result = configHelpers.parseModelIdentifier(specialChars);
+            
+            expect(result).toStrictEqual({
+                modelId: specialChars,
+                fullIdentifier: specialChars
+            });
+        });
     });
 
     describe('createModelConfig', () => {
@@ -155,6 +232,34 @@ describe('configuration_helpers', () => {
             expect(result).toBe('llama2');
             expect(optionService.getOption).toHaveBeenCalledWith('ollamaDefaultModel');
         });
+
+        // Tests for special characters in model names
+        it('should handle OpenAI model names with periods', async () => {
+            const modelName = 'gpt-4.1-turbo-preview';
+            vi.mocked(optionService.getOption).mockReturnValue(modelName);
+            
+            const result = await configHelpers.getDefaultModelForProvider('openai');
+            
+            expect(result).toBe(modelName);
+        });
+
+        it('should handle Anthropic model names with periods and @ symbols', async () => {
+            const modelName = 'claude-3.5-sonnet@20241022';
+            vi.mocked(optionService.getOption).mockReturnValue(modelName);
+            
+            const result = await configHelpers.getDefaultModelForProvider('anthropic');
+            
+            expect(result).toBe(modelName);
+        });
+
+        it('should handle Ollama model names with colons and slashes', async () => {
+            const modelName = 'library/llama3.1:70b-instruct-q4_K_M';
+            vi.mocked(optionService.getOption).mockReturnValue(modelName);
+            
+            const result = await configHelpers.getDefaultModelForProvider('ollama');
+            
+            expect(result).toBe(modelName);
+        });
     });
 
     describe('getProviderSettings', () => {
@@ -381,4 +486,122 @@ describe('configuration_helpers', () => {
             expect(() => configHelpers.clearConfigurationCache()).not.toThrow();
         });
     });
+
+    describe('getValidModelConfig', () => {
+        it('should handle model names with special characters', async () => {
+            const modelName = 'gpt-4.1-turbo@latest';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce(modelName)  // openaiDefaultModel
+                .mockReturnValueOnce('test-key')  // openaiApiKey
+                .mockReturnValueOnce('')  // openaiBaseUrl
+                .mockReturnValueOnce('');  // openaiDefaultModel
+            
+            const result = await configHelpers.getValidModelConfig('openai');
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'openai'
+            });
+        });
+
+        it('should handle Anthropic model with complex naming', async () => {
+            const modelName = 'claude-3.5-sonnet-20241022';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce(modelName)  // anthropicDefaultModel
+                .mockReturnValueOnce('anthropic-key')  // anthropicApiKey
+                .mockReturnValueOnce('')  // anthropicBaseUrl
+                .mockReturnValueOnce('');  // anthropicDefaultModel
+            
+            const result = await configHelpers.getValidModelConfig('anthropic');
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'anthropic'
+            });
+        });
+
+        it('should handle Ollama model with colons', async () => {
+            const modelName = 'custom/llama3.1:70b-q4_K_M@latest';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce(modelName)  // ollamaDefaultModel
+                .mockReturnValueOnce('http://localhost:11434')  // ollamaBaseUrl
+                .mockReturnValueOnce('');  // ollamaDefaultModel
+            
+            const result = await configHelpers.getValidModelConfig('ollama');
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'ollama'
+            });
+        });
+    });
+
+    describe('getSelectedModelConfig', () => {
+        it('should preserve OpenAI model names with special characters', async () => {
+            const modelName = 'gpt-4.1-turbo-preview@2024';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce('openai')  // aiSelectedProvider
+                .mockReturnValueOnce(modelName)  // openaiDefaultModel
+                .mockReturnValueOnce('test-key')  // openaiApiKey
+                .mockReturnValueOnce('')  // openaiBaseUrl
+                .mockReturnValueOnce('');  // openaiDefaultModel
+            
+            const result = await configHelpers.getSelectedModelConfig();
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'openai'
+            });
+        });
+
+        it('should handle model names with URL-like patterns', async () => {
+            const modelName = 'https://models.example.com/gpt-4.1';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce('openai')  // aiSelectedProvider
+                .mockReturnValueOnce(modelName)  // openaiDefaultModel
+                .mockReturnValueOnce('test-key')  // openaiApiKey
+                .mockReturnValueOnce('')  // openaiBaseUrl
+                .mockReturnValueOnce('');  // openaiDefaultModel
+            
+            const result = await configHelpers.getSelectedModelConfig();
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'openai'
+            });
+        });
+
+        it('should handle model names that look like file paths', async () => {
+            const modelName = '/models/custom/gpt-4.1.safetensors';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce('ollama')  // aiSelectedProvider
+                .mockReturnValueOnce(modelName)  // ollamaDefaultModel
+                .mockReturnValueOnce('http://localhost:11434')  // ollamaBaseUrl
+                .mockReturnValueOnce('');  // ollamaDefaultModel
+            
+            const result = await configHelpers.getSelectedModelConfig();
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'ollama'
+            });
+        });
+
+        it('should handle model names with all possible special characters', async () => {
+            const modelName = 'model!@#$%^&*()_+-=[]{}|;:\'",.<>?/~`';
+            vi.mocked(optionService.getOption)
+                .mockReturnValueOnce('anthropic')  // aiSelectedProvider
+                .mockReturnValueOnce(modelName)  // anthropicDefaultModel
+                .mockReturnValueOnce('test-key')  // anthropicApiKey
+                .mockReturnValueOnce('')  // anthropicBaseUrl
+                .mockReturnValueOnce('');  // anthropicDefaultModel
+            
+            const result = await configHelpers.getSelectedModelConfig();
+            
+            expect(result).toStrictEqual({
+                model: modelName,
+                provider: 'anthropic'
+            });
+        });
+    });
 });
\ No newline at end of file
diff --git a/apps/server/src/services/llm/providers/model_selection.spec.ts b/apps/server/src/services/llm/providers/model_selection.spec.ts
new file mode 100644
index 000000000..c6fdfae1e
--- /dev/null
+++ b/apps/server/src/services/llm/providers/model_selection.spec.ts
@@ -0,0 +1,389 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { OpenAIService } from './openai_service.js';
+import { AnthropicService } from './anthropic_service.js';
+import { OllamaService } from './ollama_service.js';
+import type { ChatCompletionOptions } from '../ai_interface.js';
+import * as providers from './providers.js';
+import options from '../../options.js';
+
+// Mock dependencies
+vi.mock('../../options.js', () => ({
+    default: {
+        getOption: vi.fn(),
+        getOptionBool: vi.fn()
+    }
+}));
+
+vi.mock('../../log.js', () => ({
+    default: {
+        info: vi.fn(),
+        error: vi.fn(),
+        warn: vi.fn()
+    }
+}));
+
+vi.mock('openai', () => ({
+    default: class MockOpenAI {
+        chat = {
+            completions: {
+                create: vi.fn()
+            }
+        };
+    }
+}));
+
+vi.mock('@anthropic-ai/sdk', () => ({
+    default: class MockAnthropic {
+        messages = {
+            create: vi.fn()
+        };
+    }
+}));
+
+vi.mock('ollama', () => ({
+    Ollama: class MockOllama {
+        chat = vi.fn();
+        show = vi.fn();
+    }
+}));
+
+describe('LLM Model Selection with Special Characters', () => {
+    beforeEach(() => {
+        vi.clearAllMocks();
+        // Set default options
+        vi.mocked(options.getOption).mockImplementation((key: string) => {
+            const optionMap: Record<string, string> = {
+                'aiEnabled': 'true',
+                'aiTemperature': '0.7',
+                'aiSystemPrompt': 'You are a helpful assistant.',
+                'openaiApiKey': 'test-api-key',
+                'openaiBaseUrl': 'https://api.openai.com/v1',
+                'anthropicApiKey': 'test-anthropic-key',
+                'anthropicBaseUrl': 'https://api.anthropic.com',
+                'ollamaBaseUrl': 'http://localhost:11434'
+            };
+            return optionMap[key] || '';
+        });
+        vi.mocked(options.getOptionBool).mockReturnValue(true);
+    });
+
+    describe('OpenAI Model Names', () => {
+        it('should correctly handle model names with periods', async () => {
+            const modelName = 'gpt-4.1-turbo-preview';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'openaiDefaultModel') return modelName;
+                return '';
+            });
+
+            const service = new OpenAIService();
+            const opts: ChatCompletionOptions = {
+                stream: false
+            };
+
+            // Spy on getOpenAIOptions to verify model name is passed correctly
+            const getOpenAIOptionsSpy = vi.spyOn(providers, 'getOpenAIOptions');
+            
+            try {
+                await service.generateChatCompletion([{ role: 'user', content: 'test' }], opts);
+            } catch (error) {
+                // Expected to fail due to mocked API
+            }
+
+            expect(getOpenAIOptionsSpy).toHaveBeenCalledWith(opts);
+            const result = getOpenAIOptionsSpy.mock.results[0].value;
+            expect(result.model).toBe(modelName);
+        });
+
+        it('should handle model names with slashes', async () => {
+            const modelName = 'openai/gpt-4/turbo-2024';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'openaiDefaultModel') return modelName;
+                return '';
+            });
+
+            const service = new OpenAIService();
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const getOpenAIOptionsSpy = vi.spyOn(providers, 'getOpenAIOptions');
+            
+            try {
+                await service.generateChatCompletion([{ role: 'user', content: 'test' }], opts);
+            } catch (error) {
+                // Expected to fail due to mocked API
+            }
+
+            const result = getOpenAIOptionsSpy.mock.results[0].value;
+            expect(result.model).toBe(modelName);
+        });
+
+        it('should handle model names with colons', async () => {
+            const modelName = 'custom:gpt-4:finetuned';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const getOpenAIOptionsSpy = vi.spyOn(providers, 'getOpenAIOptions');
+            
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+
+        it('should handle model names with underscores and hyphens', async () => {
+            const modelName = 'gpt-4_turbo-preview_v2.1';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+
+        it('should handle model names with special characters in API request', async () => {
+            const modelName = 'gpt-4.1-turbo@latest';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'openaiDefaultModel') return modelName;
+                if (key === 'openaiApiKey') return 'test-key';
+                if (key === 'openaiBaseUrl') return 'https://api.openai.com/v1';
+                return '';
+            });
+
+            const service = new OpenAIService();
+            
+            // Access the private openai client through the service
+            const client = (service as any).getClient('test-key');
+            const createSpy = vi.spyOn(client.chat.completions, 'create');
+
+            try {
+                await service.generateChatCompletion(
+                    [{ role: 'user', content: 'test' }],
+                    { stream: false }
+                );
+            } catch (error) {
+                // Expected due to mock
+            }
+
+            expect(createSpy).toHaveBeenCalledWith(
+                expect.objectContaining({
+                    model: modelName
+                })
+            );
+        });
+    });
+
+    describe('Anthropic Model Names', () => {
+        it('should correctly handle Anthropic model names with periods', async () => {
+            const modelName = 'claude-3.5-sonnet-20241022';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'anthropicDefaultModel') return modelName;
+                if (key === 'anthropicApiKey') return 'test-key';
+                return '';
+            });
+
+            const opts: ChatCompletionOptions = {
+                stream: false
+            };
+
+            const anthropicOptions = providers.getAnthropicOptions(opts);
+            expect(anthropicOptions.model).toBe(modelName);
+        });
+
+        it('should handle Anthropic model names with colons', async () => {
+            const modelName = 'anthropic:claude-3:opus';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const anthropicOptions = providers.getAnthropicOptions(opts);
+            expect(anthropicOptions.model).toBe(modelName);
+        });
+
+        it('should handle Anthropic model names in API request', async () => {
+            const modelName = 'claude-3.5-sonnet@beta';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'anthropicDefaultModel') return modelName;
+                if (key === 'anthropicApiKey') return 'test-key';
+                if (key === 'anthropicBaseUrl') return 'https://api.anthropic.com';
+                return '';
+            });
+
+            const service = new AnthropicService();
+            
+            // Access the private anthropic client
+            const client = (service as any).getClient('test-key');
+            const createSpy = vi.spyOn(client.messages, 'create');
+
+            try {
+                await service.generateChatCompletion(
+                    [{ role: 'user', content: 'test' }],
+                    { stream: false }
+                );
+            } catch (error) {
+                // Expected due to mock
+            }
+
+            expect(createSpy).toHaveBeenCalledWith(
+                expect.objectContaining({
+                    model: modelName
+                })
+            );
+        });
+    });
+
+    describe('Ollama Model Names', () => {
+        it('should correctly handle Ollama model names with colons', async () => {
+            const modelName = 'llama3.1:70b-instruct-q4_K_M';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'ollamaDefaultModel') return modelName;
+                if (key === 'ollamaBaseUrl') return 'http://localhost:11434';
+                return '';
+            });
+
+            const opts: ChatCompletionOptions = {
+                stream: false
+            };
+
+            const ollamaOptions = await providers.getOllamaOptions(opts);
+            expect(ollamaOptions.model).toBe(modelName);
+        });
+
+        it('should handle Ollama model names with slashes', async () => {
+            const modelName = 'library/mistral:7b-instruct-v0.3';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const ollamaOptions = await providers.getOllamaOptions(opts);
+            expect(ollamaOptions.model).toBe(modelName);
+        });
+
+        it('should handle Ollama model names with special characters in options', async () => {
+            const modelName = 'custom/llama3.1:70b-q4_K_M@latest';
+            vi.mocked(options.getOption).mockImplementation((key: string) => {
+                if (key === 'ollamaDefaultModel') return modelName;
+                if (key === 'ollamaBaseUrl') return 'http://localhost:11434';
+                return '';
+            });
+
+            // Test that the model name is preserved in the options
+            const opts: ChatCompletionOptions = {
+                stream: false
+            };
+
+            const ollamaOptions = await providers.getOllamaOptions(opts);
+            expect(ollamaOptions.model).toBe(modelName);
+            
+            // Also test with model specified in options
+            const optsWithModel: ChatCompletionOptions = {
+                model: 'another/model:v2.0@beta',
+                stream: false
+            };
+
+            const ollamaOptionsWithModel = await providers.getOllamaOptions(optsWithModel);
+            expect(ollamaOptionsWithModel.model).toBe('another/model:v2.0@beta');
+        });
+    });
+
+    describe('Model Name Edge Cases', () => {
+        it('should handle empty model names gracefully', () => {
+            const opts: ChatCompletionOptions = {
+                model: '',
+                stream: false
+            };
+
+            expect(() => providers.getOpenAIOptions(opts)).toThrow('No OpenAI model configured');
+        });
+
+        it('should handle model names with unicode characters', async () => {
+            const modelName = 'gpt-4-日本語-model';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+
+        it('should handle model names with spaces (encoded)', async () => {
+            const modelName = 'custom model v2.1';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+
+        it('should preserve exact model name without transformation', async () => {
+            const complexModelName = 'org/model-v1.2.3:tag@version#variant';
+            const opts: ChatCompletionOptions = {
+                model: complexModelName,
+                stream: false
+            };
+
+            // Test for all providers
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(complexModelName);
+
+            const anthropicOptions = providers.getAnthropicOptions(opts);
+            expect(anthropicOptions.model).toBe(complexModelName);
+
+            const ollamaOptions = await providers.getOllamaOptions(opts);
+            expect(ollamaOptions.model).toBe(complexModelName);
+        });
+    });
+
+    describe('Model Configuration Parsing', () => {
+        it('should not confuse provider prefix with model name containing colons', async () => {
+            // This model name has a colon but 'custom' is not a known provider
+            const modelName = 'custom:model:v1.2';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+
+        it('should handle provider prefix correctly', async () => {
+            // When model has provider prefix, it should still use the full string
+            const modelName = 'openai:gpt-4.1-turbo';
+            const opts: ChatCompletionOptions = {
+                model: modelName,
+                stream: false
+            };
+
+            const openaiOptions = providers.getOpenAIOptions(opts);
+            expect(openaiOptions.model).toBe(modelName);
+        });
+    });
+
+    describe('Integration with REST API', () => {
+        it('should pass model names correctly through REST chat service', async () => {
+            const modelName = 'gpt-4.1-turbo-preview@latest';
+            
+            // Mock the configuration helpers
+            vi.doMock('../config/configuration_helpers.js', () => ({
+                getSelectedModelConfig: vi.fn().mockResolvedValue({
+                    model: modelName,
+                    provider: 'openai'
+                }),
+                isAIEnabled: vi.fn().mockResolvedValue(true)
+            }));
+
+            const { getSelectedModelConfig } = await import('../config/configuration_helpers.js');
+            const config = await getSelectedModelConfig();
+            
+            expect(config?.model).toBe(modelName);
+        });
+    });
+});
\ No newline at end of file