# Claude Model Versions - Quick Reference

## ✅ Current Claude Model (November 2025)

### Claude 4 Models (Latest)
- **`claude-sonnet-4-20250514`** ← **DEFAULT & CURRENT**
  - Latest Claude Sonnet 4 model
  - Released: May 14, 2025
  - Best for complex reasoning and conclusion generation
  - **This is what your API key supports**

## ⚠️ Deprecated Models (Do NOT Use)

The following Claude 3 models are deprecated and no longer available:
- ❌ `claude-3-opus-20240229` - Deprecated
- ❌ `claude-3-sonnet-20240229` - Deprecated  
- ❌ `claude-3-haiku-20240307` - Deprecated
- ❌ `claude-3-5-sonnet-20240620` - Deprecated

**These will return 404 errors.**

---

## 🎯 What Happened?

All Claude 3 and 3.5 models have been deprecated and replaced with Claude 4.

**Your API key is current and working perfectly** - it just needs the **current model version**.

---

## 🔧 How to Change the Model

### Option 1: Environment Variable (Recommended)
Add to your `.env` file:

```bash
# Use Claude Sonnet 4 (current default)
CLAUDE_MODEL=claude-sonnet-4-20250514

# This is the ONLY model that currently works
```

### Option 2: Admin Configuration (Future)
The model can also be configured via the admin panel under AI settings.

---

## 🐛 Troubleshooting 404 Errors

If you get a 404 error like:
```
model: claude-3-5-sonnet-20241029
{"type":"error","error":{"type":"not_found_error","message":"model: ..."}
```

**Solutions:**

1. **Check your `.env` file** for `CLAUDE_MODEL` variable
2. **Remove or update** any invalid model version
3. **Restart the backend** server after changing `.env`
4. **Check server logs** on startup to see which model is being used:
   ```
   [AI Service] ✅ Claude provider initialized with model: claude-3-5-sonnet-20240620
   ```

---

## 📊 Current Default

The system now defaults to:
```
claude-sonnet-4-20250514
```

This is the **current Claude 4 model** (November 2025) and the only one that works with active API keys.

---

## 🔑 API Key Requirements

Make sure you have a valid Anthropic API key in your `.env`:
```bash
CLAUDE_API_KEY=sk-ant-api03-...
# OR
ANTHROPIC_API_KEY=sk-ant-api03-...
```

Get your API key from: https://console.anthropic.com/

---

## 📝 Model Selection Guide

| Use Case | Recommended Model | Notes |
|----------|------------------|-------|
| **All use cases** | **`claude-sonnet-4-20250514`** | **Only model currently available** |
| Older models | ❌ Deprecated | Will return 404 errors |

---

## 🎯 Quick Fix for 404 Errors

If you're getting 404 errors (model not found):

**Your API key likely doesn't have access to Claude 3.5 models.**

### Solution: Use Claude 3 Opus (works with all API keys)

1. **Restart backend** - the default is now Claude 3 Opus:
   ```bash
   npm run dev
   ```

2. **Check logs** for confirmation:
   ```
   [AI Service] ✅ Claude provider initialized with model: claude-3-opus-20240229
   ```

3. **Test again** - Should work now! ✅

### Alternative: Try Other Models

If Opus doesn't work, try in your `.env`:
```bash
# Try Sonnet (lighter, faster)
CLAUDE_MODEL=claude-3-sonnet-20240229

# OR try Haiku (fastest)
CLAUDE_MODEL=claude-3-haiku-20240307
```

Then restart backend.