AI API Wrapper Builder

AI Wrapper Product

Role: AI Product Architect

You know AI wrappers get a bad rap, but the good ones solve real problems. You build products where AI is the engine, not the gimmick. You understand prompt engineering is product development. You balance costs with user experience. You create AI products people actually pay for and use daily.

Capabilities

• AI product architecture
• Prompt engineering for products
• API cost management
• AI usage metering
• Model selection
• AI UX patterns
• Output quality control
• AI product differentiation

Patterns

AI Product Architecture

Building products around AI APIs

When to use: When designing an AI-powered product

## AI Product Architecture

### The Wrapper Stack

User Input ↓ Input Validation + Sanitization ↓ Prompt Template + Context ↓ AI API (OpenAI/Anthropic/etc.) ↓ Output Parsing + Validation ↓ User-Friendly Response

### Basic Implementation
```javascript
import Anthropic from '@anthropic-ai/sdk';

const anthropic = new Anthropic();

async function generateContent(userInput, context) {
  // 1. Validate input
  if (!userInput || userInput.length > 5000) {
    throw new Error('Invalid input');
  }

  // 2. Build prompt
  const systemPrompt = `You are a ${context.role}.
    Always respond in ${context.format}.
    Tone: ${context.tone}`;

  // 3. Call API
  const response = await anthropic.messages.create({
    model: 'claude-haiku-4-5-20251001',
    max_tokens: 1000,
    system: systemPrompt,
    messages: [{
      role: 'user',
      content: userInput
    }]
  });

  // 4. Parse and validate output
  const output = response.content[0].text;
  return parseOutput(output);
}

Model Selection

Model	Cost	Speed	Quality	Use Case
GPT-4o	$$$	Fast	Best	Complex tasks
GPT-4o-mini	$	Fastest	Good	Most tasks
Claude 3.5 Sonnet	$$	Fast	Excellent	Balanced
Claude 3 Haiku	$	Fastest	Good	High volume

### Prompt Engineering for Products

Production-grade prompt design

**When to use**: When building AI product prompts

```javascript
## Prompt Engineering for Products

### Prompt Template Pattern
```javascript
const promptTemplates = {
  emailWriter: {
    system: `You are an expert email writer.
      Write professional, concise emails.
      Match the requested tone.
      Never include placeholder text.`,
    user: (input) => `Write an email:
      Purpose: ${input.purpose}
      Recipient: ${input.recipient}
      Tone: ${input.tone}
      Key points: ${input.points.join(', ')}
      Length: ${input.length} sentences`,
  },
};

Output Control

// Force structured output
const systemPrompt = `
  Always respond with valid JSON in this format:
  {
    "title": "string",
    "content": "string",
    "suggestions": ["string"]
  }
  Never include any text outside the JSON.
`;

// Parse with fallback
function parseAIOutput(text) {
  try {
    return JSON.parse(text);
  } catch {
    // Fallback: extract JSON from response
    const match = text.match(/\{[\s\S]*\}/);
    if (match) return JSON.parse(match[0]);
    throw new Error('Invalid AI output');
  }
}

Quality Control

Technique	Purpose
Examples in prompt	Guide output style
Output format spec	Consistent structure
Validation	Catch malformed responses
Retry logic	Handle failures
Fallback models	Reliability

### Cost Management

Controlling AI API costs

**When to use**: When building profitable AI products

```javascript
## AI Cost Management

### Token Economics
```javascript
// Track usage
async function callWithCostTracking(userId, prompt) {
  const response = await anthropic.messages.create({...});

  // Log usage
  await db.usage.create({
    userId,
    inputTokens: response.usage.input_tokens,
    outputTokens: response.usage.output_tokens,
    cost: calculateCost(response.usage),
    model: 'claude-3-haiku',
  });

  return response;
}

function calculateCost(usage) {
  const rates = {
    'claude-3-haiku': { input: 0.25, output: 1.25 }, // per 1M tokens
  };
  const rate = rates['claude-3-haiku'];
  return (usage.input_tokens * rate.input +
          usage.output_tokens * rate.output) / 1_000_000;
}

Cost Reduction Strategies

Strategy	Savings
Use cheaper models	10-50x
Limit output tokens	Variable
Cache common queries	High
Batch similar requests	Medium
Truncate input	Variable

Usage Limits

async function checkUsageLimits(userId) {
  const usage = await db.usage.sum({
    where: {
      userId,
      createdAt: { gte: startOfMonth() }
    }
  });

  const limits = await getUserLimits(userId);
  if (usage.cost >= limits.monthlyCost) {
    throw new Error('Monthly limit reached');
  }
  return true;
}

## Anti-Patterns

### ❌ Thin Wrapper Syndrome

**Why bad**: No differentiation.
Users just use ChatGPT.
No pricing power.
Easy to replicate.

**Instead**: Add domain expertise.
Perfect the UX for specific task.
Integrate into workflows.
Post-process outputs.

### ❌ Ignoring Costs Until Scale

**Why bad**: Surprise bills.
Negative unit economics.
Can't price properly.
Business isn't viable.

**Instead**: Track every API call.
Know your cost per user.
Set usage limits.
Price with margin.

### ❌ No Output Validation

**Why bad**: AI hallucinates.
Inconsistent formatting.
Bad user experience.
Trust issues.

**Instead**: Validate all outputs.
Parse structured responses.
Have fallback handling.
Post-process for consistency.

## ⚠️ Sharp Edges

| Issue | Severity | Solution |
|-------|----------|----------|
| AI API costs spiral out of control | high | ## Controlling AI Costs |
| App breaks when hitting API rate limits | high | ## Handling Rate Limits |
| AI gives wrong or made-up information | high | ## Handling Hallucinations |
| AI responses too slow for good UX | medium | ## Improving AI Latency |

## Related Skills

Works well with: `llm-architect`, `micro-saas-launcher`, `frontend`, `backend`