feat(docs): add structured output example and details

README.md

@@ -12,6 +12,7 @@ A professional, type-safe TypeScript package that provides a unified interface f
 - 🔧 **Configurable**: Extensive configuration options for each provider
 - 📦 **Zero Dependencies**: Lightweight with minimal external dependencies
 - 🌐 **Local Support**: OpenWebUI integration for local/private AI models
+- 🎨 **Structured Output**: Define custom response types for type-safe AI outputs
 
 ## 🚀 Quick Start
 
@@ -83,6 +84,69 @@ const openwebui = createOpenWebUIProvider({ apiKey: 'your-key', baseUrl: 'http:/
 const provider = createProvider('claude', { apiKey: 'your-key' });
 ```
 
+## 🎨 Structured Response Types
+
+Define custom response types for type-safe, structured AI outputs:
+
+```typescript
+import { createResponseType, validateResponseType } from 'simple-ai-provider';
+
+// Define your response type
+interface UserProfile {
+  name: string;
+  age: number;
+  email: string;
+  preferences: {
+    theme: 'light' | 'dark';
+    notifications: boolean;
+  };
+}
+
+const userProfileType = createResponseType<UserProfile>(
+  `{
+    name: string;
+    age: number;
+    email: string;
+    preferences: {
+      theme: 'light' | 'dark';
+      notifications: boolean;
+    };
+  }`,
+  'A user profile with personal information and preferences',
+  {
+    name: 'John Doe',
+    age: 30,
+    email: 'john@example.com',
+    preferences: { theme: 'dark', notifications: true }
+  }
+);
+
+// Use with any provider
+const response = await claude.complete({
+  messages: [
+    { role: 'user', content: 'Generate a user profile for a software developer' }
+  ],
+  responseType: userProfileType,
+  maxTokens: 500
+});
+
+// Validate and get typed response
+const validation = validateResponseType(response.content, userProfileType);
+if (validation.isValid) {
+  const userProfile = validation.data as UserProfile;
+  console.log(`Name: ${userProfile.name}`);
+  console.log(`Theme: ${userProfile.preferences.theme}`);
+}
+```
+
+### Key Benefits
+
+- **Type Safety**: Get fully typed responses from AI providers
+- **Automatic Prompting**: System prompts are automatically generated
+- **Validation**: Built-in response validation and parsing
+- **Consistency**: Ensures AI outputs match your expected format
+- **Developer Experience**: IntelliSense and compile-time type checking
+
 ## 📝 Environment Variables
 
 Set up your API keys:

examples/structured-response-types.ts

@@ -0,0 +1,377 @@
+/**
+ * Structured Response Types Example
+ * 
+ * This example demonstrates how to use custom response types to get
+ * structured, type-safe outputs from AI providers. The library automatically
+ * generates system prompts that instruct the AI on the expected output format.
+ */
+
+import { 
+  createClaudeProvider, 
+  createResponseType, 
+  validateResponseType,
+  AIProviderError, 
+  AIErrorType 
+} from '../src/index.js';
+
+// ============================================================================
+// DEFINE CUSTOM RESPONSE TYPES
+// ============================================================================
+
+// Example 1: User Profile Type
+interface UserProfile {
+  name: string;
+  age: number;
+  email: string;
+  preferences: {
+    theme: 'light' | 'dark';
+    notifications: boolean;
+  };
+  skills: string[];
+}
+
+const userProfileType = createResponseType<UserProfile>(
+  `{
+    name: string;
+    age: number;
+    email: string;
+    preferences: {
+      theme: 'light' | 'dark';
+      notifications: boolean;
+    };
+    skills: string[];
+  }`,
+  'A user profile with personal information, preferences, and skills',
+  {
+    name: 'John Doe',
+    age: 30,
+    email: 'john@example.com',
+    preferences: { theme: 'dark', notifications: true },
+    skills: ['TypeScript', 'React', 'Node.js']
+  }
+);
+
+// Example 2: Product Analysis Type
+interface ProductAnalysis {
+  productName: string;
+  category: string;
+  priceRange: 'budget' | 'mid-range' | 'premium';
+  pros: string[];
+  cons: string[];
+  overallRating: number; // 1-10 scale
+  recommendation: 'buy' | 'consider' | 'avoid';
+  reasoning: string;
+}
+
+const productAnalysisType = createResponseType<ProductAnalysis>(
+  `{
+    productName: string;
+    category: string;
+    priceRange: 'budget' | 'mid-range' | 'premium';
+    pros: string[];
+    cons: string[];
+    overallRating: number;
+    recommendation: 'buy' | 'consider' | 'avoid';
+    reasoning: string;
+  }`,
+  'A comprehensive product analysis with pros, cons, rating, and recommendation',
+  {
+    productName: 'Example Product',
+    category: 'Electronics',
+    priceRange: 'mid-range',
+    pros: ['Good build quality', 'Reasonable price'],
+    cons: ['Limited features', 'Short warranty'],
+    overallRating: 7,
+    recommendation: 'consider',
+    reasoning: 'Good value for money but has some limitations'
+  }
+);
+
+// Example 3: Code Review Type
+interface CodeReview {
+  overallScore: number; // 1-10 scale
+  issues: Array<{
+    type: 'error' | 'warning' | 'suggestion';
+    line?: number;
+    message: string;
+    severity: 'low' | 'medium' | 'high';
+  }>;
+  strengths: string[];
+  improvements: string[];
+  summary: string;
+}
+
+const codeReviewType = createResponseType<CodeReview>(
+  `{
+    overallScore: number;
+    issues: Array<{
+      type: 'error' | 'warning' | 'suggestion';
+      line?: number;
+      message: string;
+      severity: 'low' | 'medium' | 'high';
+    }>;
+    strengths: string[];
+    improvements: string[];
+    summary: string;
+  }`,
+  'A comprehensive code review with scoring, issues, and recommendations',
+  {
+    overallScore: 8,
+    issues: [
+      { type: 'warning', line: 15, message: 'Consider using const instead of let', severity: 'low' }
+    ],
+    strengths: ['Clear variable names', 'Good error handling'],
+    improvements: ['Add more comments', 'Consider refactoring large functions'],
+    summary: 'Well-written code with minor improvements needed'
+  }
+);
+
+// ============================================================================
+// EXAMPLE FUNCTIONS
+// ============================================================================
+
+async function demonstrateUserProfileGeneration() {
+  console.log('\n=== User Profile Generation Example ===');
+  
+  const claude = createClaudeProvider(process.env.ANTHROPIC_API_KEY || 'your-api-key-here');
+  await claude.initialize();
+
+  try {
+    const response = await claude.complete({
+      messages: [
+        { 
+          role: 'user', 
+          content: 'Generate a realistic user profile for a software developer who loves open source projects and prefers dark themes.' 
+        }
+      ],
+      responseType: userProfileType,
+      maxTokens: 500,
+      temperature: 0.7
+    });
+
+    console.log('Raw response:', response.content);
+    
+    // Validate and parse the response
+    const validation = validateResponseType(response.content, userProfileType);
+    
+    if (validation.isValid) {
+      const userProfile = validation.data as UserProfile;
+      console.log('\nParsed User Profile:');
+      console.log(`Name: ${userProfile.name}`);
+      console.log(`Age: ${userProfile.age}`);
+      console.log(`Email: ${userProfile.email}`);
+      console.log(`Theme Preference: ${userProfile.preferences.theme}`);
+      console.log(`Notifications: ${userProfile.preferences.notifications}`);
+      console.log(`Skills: ${userProfile.skills.join(', ')}`);
+    } else {
+      console.error('Validation failed:', validation.error);
+    }
+
+  } catch (error) {
+    if (error instanceof AIProviderError) {
+      console.error(`AI Provider Error (${error.type}):`, error.message);
+    } else {
+      console.error('Unexpected error:', error);
+    }
+  }
+}
+
+async function demonstrateProductAnalysis() {
+  console.log('\n=== Product Analysis Example ===');
+  
+  const claude = createClaudeProvider(process.env.ANTHROPIC_API_KEY || 'your-api-key-here');
+  await claude.initialize();
+
+  try {
+    const response = await claude.complete({
+      messages: [
+        { 
+          role: 'user', 
+          content: 'Analyze the iPhone 15 Pro from a consumer perspective. Consider its features, price point, and market position.' 
+        }
+      ],
+      responseType: productAnalysisType,
+      maxTokens: 800,
+      temperature: 0.5
+    });
+
+    console.log('Raw response:', response.content);
+    
+    const validation = validateResponseType(response.content, productAnalysisType);
+    
+    if (validation.isValid) {
+      const analysis = validation.data as ProductAnalysis;
+      console.log('\nProduct Analysis:');
+      console.log(`Product: ${analysis.productName}`);
+      console.log(`Category: ${analysis.category}`);
+      console.log(`Price Range: ${analysis.priceRange}`);
+      console.log(`Overall Rating: ${analysis.overallRating}/10`);
+      console.log(`Recommendation: ${analysis.recommendation}`);
+      console.log(`Pros: ${analysis.pros.join(', ')}`);
+      console.log(`Cons: ${analysis.cons.join(', ')}`);
+      console.log(`Reasoning: ${analysis.reasoning}`);
+    } else {
+      console.error('Validation failed:', validation.error);
+    }
+
+  } catch (error) {
+    if (error instanceof AIProviderError) {
+      console.error(`AI Provider Error (${error.type}):`, error.message);
+    } else {
+      console.error('Unexpected error:', error);
+    }
+  }
+}
+
+async function demonstrateCodeReview() {
+  console.log('\n=== Code Review Example ===');
+  
+  const claude = createClaudeProvider(process.env.ANTHROPIC_API_KEY || 'your-api-key-here');
+  await claude.initialize();
+
+  const sampleCode = `
+function calculateTotal(items) {
+  let total = 0;
+  for (let i = 0; i < items.length; i++) {
+    total += items[i].price;
+  }
+  return total;
+}
+
+function processPayment(amount, cardNumber) {
+  if (amount <= 0) {
+    throw new Error("Invalid amount");
+  }
+  // Process payment logic here
+  return { success: true, transactionId: "12345" };
+}
+  `;
+
+  try {
+    const response = await claude.complete({
+      messages: [
+        { 
+          role: 'user', 
+          content: `Please review this JavaScript code and provide a comprehensive analysis:\n\n\`\`\`javascript\n${sampleCode}\n\`\`\`` 
+        }
+      ],
+      responseType: codeReviewType,
+      maxTokens: 1000,
+      temperature: 0.3
+    });
+
+    console.log('Raw response:', response.content);
+    
+    const validation = validateResponseType(response.content, codeReviewType);
+    
+    if (validation.isValid) {
+      const review = validation.data as CodeReview;
+      console.log('\nCode Review:');
+      console.log(`Overall Score: ${review.overallScore}/10`);
+      console.log(`Summary: ${review.summary}`);
+      console.log(`\nStrengths:`);
+      review.strengths.forEach(strength => console.log(`  • ${strength}`));
+      console.log(`\nImprovements:`);
+      review.improvements.forEach(improvement => console.log(`  • ${improvement}`));
+      console.log(`\nIssues:`);
+      review.issues.forEach(issue => {
+        const lineInfo = issue.line ? ` (line ${issue.line})` : '';
+        console.log(`  • [${issue.severity.toUpperCase()}] ${issue.type}: ${issue.message}${lineInfo}`);
+      });
+    } else {
+      console.error('Validation failed:', validation.error);
+    }
+
+  } catch (error) {
+    if (error instanceof AIProviderError) {
+      console.error(`AI Provider Error (${error.type}):`, error.message);
+    } else {
+      console.error('Unexpected error:', error);
+    }
+  }
+}
+
+async function demonstrateStreamingWithResponseType() {
+  console.log('\n=== Streaming with Response Type Example ===');
+  
+  const claude = createClaudeProvider(process.env.ANTHROPIC_API_KEY || 'your-api-key-here');
+  await claude.initialize();
+
+  try {
+    console.log('Streaming response for product analysis...\n');
+    
+    let fullResponse = '';
+    for await (const chunk of claude.stream({
+      messages: [
+        { 
+          role: 'user', 
+          content: 'Analyze the Tesla Model 3 as a consumer product.' 
+        }
+      ],
+      responseType: productAnalysisType,
+      maxTokens: 600,
+      temperature: 0.5
+    })) {
+      if (!chunk.isComplete) {
+        process.stdout.write(chunk.content);
+        fullResponse += chunk.content;
+      } else {
+        console.log('\n\nStream completed. Usage:', chunk.usage);
+        
+        // Validate the complete streamed response
+        const validation = validateResponseType(fullResponse, productAnalysisType);
+        if (validation.isValid) {
+          console.log('\nStreamed response validation: SUCCESS');
+        } else {
+          console.log('\nStreamed response validation: FAILED -', validation.error);
+        }
+      }
+    }
+
+  } catch (error) {
+    if (error instanceof AIProviderError) {
+      console.error(`AI Provider Error (${error.type}):`, error.message);
+    } else {
+      console.error('Unexpected error:', error);
+    }
+  }
+}
+
+// ============================================================================
+// MAIN EXECUTION
+// ============================================================================
+
+async function main() {
+  console.log('🚀 Structured Response Types Example');
+  console.log('=====================================');
+  
+  // Check for API key
+  if (!process.env.ANTHROPIC_API_KEY) {
+    console.error('❌ Please set ANTHROPIC_API_KEY environment variable');
+    console.log('You can get an API key from: https://console.anthropic.com/');
+    return;
+  }
+
+  try {
+    await demonstrateUserProfileGeneration();
+    await demonstrateProductAnalysis();
+    await demonstrateCodeReview();
+    await demonstrateStreamingWithResponseType();
+    
+    console.log('\n✅ All examples completed successfully!');
+    console.log('\nKey Benefits of Response Types:');
+    console.log('• Type-safe AI responses');
+    console.log('• Automatic system prompt generation');
+    console.log('• Built-in response validation');
+    console.log('• Consistent output format');
+    console.log('• Better error handling');
+    
+  } catch (error) {
+    console.error('❌ Example failed:', error);
+  }
+}
+
+// Run the example
+if (import.meta.main) {
+  main().catch(console.error);
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "simple-ai-provider",
-  "version": "1.1.2",
+  "version": "1.2.0",
   "description": "A simple and extensible AI provider package for easy integration of multiple AI services",
   "main": "dist/index.js",
   "module": "dist/index.mjs",
@@ -40,7 +40,10 @@
     "nodejs",
     "openwebui",
     "llm",
-    "unified-api"
+    "unified-api",
+    "structured-output",
+    "response-types",
+    "type-safe"
   ],
   "author": "Jan-Marlon Leibl",
   "license": "MIT",

src/index.ts

@@ -16,12 +16,20 @@ export type {
   CompletionResponse,
   CompletionChunk,
   ProviderInfo,
-  TokenUsage
+  TokenUsage,
+  ResponseType
 } from './types/index.js';
 
 // Error types
 export { AIProviderError, AIErrorType } from './types/index.js';
 
+// Response type utilities
+export { 
+  createResponseType, 
+  generateResponseTypePrompt, 
+  validateResponseType 
+} from './types/index.js';
+
 // Base provider
 export { BaseAIProvider } from './providers/base.js';
 
@@ -50,4 +58,4 @@ export const SUPPORTED_PROVIDERS = ['claude', 'openai', 'gemini', 'openwebui'] a
 /**
  * Package version
  */
-export const VERSION = '1.0.0'; 
+export const VERSION = '1.2.0'; 

src/providers/base.ts

@@ -19,9 +19,10 @@ import type {
   CompletionParams,
   CompletionResponse,
   CompletionChunk,
-  ProviderInfo
+  ProviderInfo,
+  ResponseType
 } from '../types/index.js';
-import { AIProviderError, AIErrorType } from '../types/index.js';
+import { AIProviderError, AIErrorType, generateResponseTypePrompt } from '../types/index.js';
 
 // ============================================================================
 // ABSTRACT BASE PROVIDER CLASS
@@ -147,7 +148,7 @@ export abstract class BaseAIProvider {
    * console.log(response.content);
    * ```
    */
-  public async complete(params: CompletionParams): Promise<CompletionResponse> {
+  public async complete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse> {
     // Ensure provider is ready for use
     this.ensureInitialized();
     
@@ -155,8 +156,11 @@ export abstract class BaseAIProvider {
     this.validateCompletionParams(params);
 
     try {
+      // Process response type instructions if specified
+      const processedParams = this.processResponseType(params);
+      
       // Delegate to provider-specific implementation
-      return await this.doComplete(params);
+      return await this.doComplete(processedParams);
     } catch (error) {
       // Normalize error to our standard format
       throw this.normalizeError(error as Error);
@@ -184,7 +188,7 @@ export abstract class BaseAIProvider {
    * }
    * ```
    */
-  public async *stream(params: CompletionParams): AsyncIterable<CompletionChunk> {
+  public async *stream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk> {
     // Ensure provider is ready for use
     this.ensureInitialized();
     
@@ -192,8 +196,11 @@ export abstract class BaseAIProvider {
     this.validateCompletionParams(params);
 
     try {
+      // Process response type instructions if specified
+      const processedParams = this.processResponseType(params);
+      
       // Delegate to provider-specific implementation
-      yield* this.doStream(params);
+      yield* this.doStream(processedParams);
     } catch (error) {
       // Normalize error to our standard format
       throw this.normalizeError(error as Error);
@@ -242,7 +249,7 @@ export abstract class BaseAIProvider {
    * @returns Promise resolving to completion response
    * @throws {Error} If completion fails (will be normalized to AIProviderError)
    */
-  protected abstract doComplete(params: CompletionParams): Promise<CompletionResponse>;
+  protected abstract doComplete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse>;
 
   /**
    * Provider-specific streaming implementation.
@@ -256,7 +263,7 @@ export abstract class BaseAIProvider {
    * @returns AsyncIterable yielding completion chunks
    * @throws {Error} If streaming fails (will be normalized to AIProviderError)
    */
-  protected abstract doStream(params: CompletionParams): AsyncIterable<CompletionChunk>;
+  protected abstract doStream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk>;
 
   // ========================================================================
   // PROTECTED UTILITY METHODS
@@ -370,7 +377,7 @@ export abstract class BaseAIProvider {
    * @param params - Parameters to validate
    * @throws {AIProviderError} If any parameter is invalid
    */
-  protected validateCompletionParams(params: CompletionParams): void {
+  protected validateCompletionParams<T = any>(params: CompletionParams<T>): void {
     if (!params || typeof params !== 'object') {
       throw new AIProviderError(
         'Completion parameters object is required',
@@ -512,6 +519,45 @@ export abstract class BaseAIProvider {
     }
   }
 
+  /**
+   * Processes completion parameters to include response type instructions.
+   * 
+   * This method automatically adds system prompt instructions when a response
+   * type is specified, ensuring the AI understands the expected output format.
+   * 
+   * @protected
+   * @param params - Original completion parameters
+   * @returns Processed parameters with response type instructions
+   */
+  protected processResponseType<T>(params: CompletionParams<T>): CompletionParams<T> {
+    if (!params.responseType) {
+      return params;
+    }
+
+    // Create a copy of the parameters to avoid mutation
+    const processedParams = { ...params };
+    
+    // Generate the response type instruction
+    const responseTypePrompt = generateResponseTypePrompt(params.responseType);
+    
+    // Find existing system messages or create new ones
+    const systemMessages = params.messages.filter(msg => msg.role === 'system');
+    const nonSystemMessages = params.messages.filter(msg => msg.role !== 'system');
+    
+    // Combine existing system messages with response type instruction
+    const combinedSystemContent = systemMessages.length > 0
+      ? systemMessages.map(msg => msg.content).join('\n\n') + '\n\n' + responseTypePrompt
+      : responseTypePrompt;
+    
+    // Create new messages array with combined system message
+    processedParams.messages = [
+      { role: 'system', content: combinedSystemContent },
+      ...nonSystemMessages
+    ];
+    
+    return processedParams;
+  }
+
   /**
    * Normalizes any error into a standardized AIProviderError.
    * 

src/providers/claude.ts

@@ -220,7 +220,7 @@ export class ClaudeProvider extends BaseAIProvider {
    * @returns Promise resolving to formatted completion response
    * @throws {Error} If API request fails
    */
-  protected async doComplete(params: CompletionParams): Promise<CompletionResponse> {
+  protected async doComplete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse> {
     if (!this.client) {
       throw new AIProviderError('Claude client not initialized', AIErrorType.INVALID_REQUEST);
     }
@@ -257,7 +257,7 @@ export class ClaudeProvider extends BaseAIProvider {
    * @returns AsyncIterable yielding completion chunks
    * @throws {Error} If streaming request fails
    */
-  protected async *doStream(params: CompletionParams): AsyncIterable<CompletionChunk> {
+  protected async *doStream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk> {
     if (!this.client) {
       throw new AIProviderError('Claude client not initialized', AIErrorType.INVALID_REQUEST);
     }

src/providers/gemini.ts

@@ -268,7 +268,7 @@ export class GeminiProvider extends BaseAIProvider {
    * @returns Promise resolving to formatted completion response
    * @throws {Error} If API request fails
    */
-  protected async doComplete(params: CompletionParams): Promise<CompletionResponse> {
+  protected async doComplete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse> {
     if (!this.client || !this.model) {
       throw new AIProviderError('Gemini client not initialized', AIErrorType.INVALID_REQUEST);
     }
@@ -324,7 +324,7 @@ export class GeminiProvider extends BaseAIProvider {
    * @returns AsyncIterable yielding completion chunks
    * @throws {Error} If streaming request fails
    */
-  protected async *doStream(params: CompletionParams): AsyncIterable<CompletionChunk> {
+  protected async *doStream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk> {
     if (!this.client || !this.model) {
       throw new AIProviderError('Gemini client not initialized', AIErrorType.INVALID_REQUEST);
     }

src/providers/openai.ts

@@ -244,7 +244,7 @@ export class OpenAIProvider extends BaseAIProvider {
    * @returns Promise resolving to formatted completion response
    * @throws {Error} If API request fails
    */
-  protected async doComplete(params: CompletionParams): Promise<CompletionResponse> {
+  protected async doComplete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse> {
     if (!this.client) {
       throw new AIProviderError('OpenAI client not initialized', AIErrorType.INVALID_REQUEST);
     }
@@ -278,7 +278,7 @@ export class OpenAIProvider extends BaseAIProvider {
    * @returns AsyncIterable yielding completion chunks
    * @throws {Error} If streaming request fails
    */
-  protected async *doStream(params: CompletionParams): AsyncIterable<CompletionChunk> {
+  protected async *doStream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk> {
     if (!this.client) {
       throw new AIProviderError('OpenAI client not initialized', AIErrorType.INVALID_REQUEST);
     }

src/providers/openwebui.ts

@@ -962,7 +962,7 @@ export class OpenWebUIProvider extends BaseAIProvider {
    * @returns Promise resolving to formatted completion response
    * @throws {Error} If API request fails
    */
-  protected async doComplete(params: CompletionParams): Promise<CompletionResponse> {
+  protected async doComplete<T = any>(params: CompletionParams<T>): Promise<CompletionResponse> {
     if (this.useOllamaProxy) {
       return this.completeWithOllama(params);
     } else {
@@ -978,7 +978,7 @@ export class OpenWebUIProvider extends BaseAIProvider {
    * @returns AsyncIterable yielding completion chunks
    * @throws {Error} If streaming request fails
    */
-  protected async *doStream(params: CompletionParams): AsyncIterable<CompletionChunk> {
+  protected async *doStream<T = any>(params: CompletionParams<T>): AsyncIterable<CompletionChunk> {
     if (this.useOllamaProxy) {
       yield* this.streamWithOllama(params);
     } else {

src/types/index.ts

@@ -36,10 +36,24 @@ export interface AIMessage {
   metadata?: Record<string, any>;
 }
 
+/**
+ * Response type definition for structured AI outputs
+ */
+export interface ResponseType<T = any> {
+  /** The TypeScript type definition as a string */
+  typeDefinition: string;
+  /** Human-readable description of the expected response format */
+  description: string;
+  /** Example of the expected response structure */
+  example?: T;
+  /** Whether to enforce strict JSON formatting */
+  strictJson?: boolean;
+}
+
 /**
  * Parameters for AI completion requests
  */
-export interface CompletionParams {
+export interface CompletionParams<T = any> {
   /** Array of messages forming the conversation */
   messages: AIMessage[];
   /** Model to use for completion */
@@ -54,6 +68,8 @@ export interface CompletionParams {
   stopSequences?: string[];
   /** Whether to stream the response */
   stream?: boolean;
+  /** Expected response type for structured outputs */
+  responseType?: ResponseType<T>;
   /** Additional provider-specific parameters */
   [key: string]: any;
 }
@@ -144,4 +160,115 @@ export interface ProviderInfo {
   supportsStreaming: boolean;
   /** Additional capabilities */
   capabilities?: Record<string, any>;
+}
+
+// ============================================================================
+// RESPONSE TYPE UTILITIES
+// ============================================================================
+
+/**
+ * Creates a response type definition for structured AI outputs
+ * 
+ * @param typeDefinition - TypeScript type definition as a string
+ * @param description - Human-readable description of the expected format
+ * @param example - Optional example of the expected response structure
+ * @param strictJson - Whether to enforce strict JSON formatting (default: true)
+ * @returns ResponseType object for use in completion requests
+ * 
+ * @example
+ * ```typescript
+ * const userType = createResponseType(
+ *   `{
+ *     name: string;
+ *     age: number;
+ *     email: string;
+ *     preferences: {
+ *       theme: 'light' | 'dark';
+ *       notifications: boolean;
+ *     };
+ *   }`,
+ *   'A user profile with personal information and preferences',
+ *   {
+ *     name: 'John Doe',
+ *     age: 30,
+ *     email: 'john@example.com',
+ *     preferences: { theme: 'dark', notifications: true }
+ *   }
+ * );
+ * ```
+ */
+export function createResponseType<T = any>(
+  typeDefinition: string,
+  description: string,
+  example?: T,
+  strictJson: boolean = true
+): ResponseType<T> {
+  return {
+    typeDefinition: typeDefinition.trim(),
+    description,
+    example,
+    strictJson
+  };
+}
+
+/**
+ * Generates a system prompt instruction for structured output based on response type
+ * 
+ * @param responseType - The response type definition
+ * @returns Formatted system prompt instruction
+ */
+export function generateResponseTypePrompt(responseType: ResponseType): string {
+  const { typeDefinition, description, example, strictJson } = responseType;
+  
+  let prompt = `You must respond with a JSON object that matches the following TypeScript type definition:\n\n`;
+  prompt += `Type Definition:\n\`\`\`typescript\n${typeDefinition}\n\`\`\`\n\n`;
+  prompt += `Description: ${description}\n\n`;
+  
+  if (example) {
+    prompt += `Example:\n\`\`\`json\n${JSON.stringify(example, null, 2)}\n\`\`\`\n\n`;
+  }
+  
+  if (strictJson) {
+    prompt += `IMPORTANT: Your response must be valid JSON only. Do not include any text before or after the JSON object. Do not use markdown formatting.`;
+  } else {
+    prompt += `Your response should follow the structure defined above.`;
+  }
+  
+  return prompt;
+}
+
+/**
+ * Validates that a response matches the expected type structure
+ * 
+ * @param response - The response content to validate
+ * @param responseType - The expected response type
+ * @returns Object with validation result and parsed data
+ */
+export function validateResponseType<T = any>(
+  response: string,
+  responseType: ResponseType<T>
+): { isValid: boolean; data?: T; error?: string } {
+  try {
+    // Parse JSON response
+    const parsed = JSON.parse(response);
+    
+    // Basic validation - in a real implementation, you might want to use
+    // a schema validation library like zod or ajv for more thorough validation
+    if (typeof parsed !== 'object' || parsed === null) {
+      return {
+        isValid: false,
+        error: 'Response must be a JSON object'
+      };
+    }
+    
+    return {
+      isValid: true,
+      data: parsed as T
+    };
+  } catch (error) {
+    return {
+      isValid: false,
+      error: `Invalid JSON: ${(error as Error).message}`
+    };
+  }
 }