# 🔧 Critical Fixes Applied to RAG Pipeline
## Summary
This document details all critical security and multi-tenant isolation fixes applied to the RAG backend.
---
## 🔴 Critical Fix #1: Multi-Tenant Isolation
### Problem
- Missing `tenant_id` in metadata and filtering
- Risk of data leakage between tenants
- Shared collection without proper isolation
### Fix Applied
**Files Modified:**
- `app/models/schemas.py` - Added `tenant_id` to all request/response models
- `app/rag/chunking.py` - Added `tenant_id` parameter to metadata creation
- `app/rag/retrieval.py` - Added `tenant_id` to all retrieval queries
- `app/rag/vectorstore.py` - Added `tenant_id` filtering to all operations
- `app/main.py` - Added `tenant_id` to all endpoints
**Changes:**
```python
# Before
filter_dict = {"kb_id": kb_id, "user_id": user_id}
# After
filter_dict = {
"tenant_id": tenant_id, # CRITICAL: Multi-tenant isolation
"kb_id": kb_id,
"user_id": user_id
}
```
**Impact:** All queries now require `tenant_id`, ensuring complete data isolation.
---
## 🔴 Critical Fix #2: Enhanced Security
### Problem
- CORS allows all origins (`*`)
- No file size validation
- No input sanitization
### Fix Applied
**Files Modified:**
- `app/config.py` - Added security settings
- `app/main.py` - Added file size validation, restricted CORS
**Changes:**
```python
# CORS - Restricted
allowed_origins = settings.ALLOWED_ORIGINS.split(",") if settings.ALLOWED_ORIGINS != "*" else ["*"]
app.add_middleware(
CORSMiddleware,
allow_origins=allowed_origins,
allow_methods=["GET", "POST", "DELETE"], # Restricted
allow_headers=["Content-Type", "Authorization"], # Restricted
)
# File Size Validation
max_size_bytes = settings.MAX_FILE_SIZE_MB * 1024 * 1024
if file_size > max_size_bytes:
raise HTTPException(status_code=400, detail=f"File too large. Maximum: {settings.MAX_FILE_SIZE_MB}MB")
```
**Impact:** Reduced attack surface, prevented DoS via large files.
---
## 🔴 Critical Fix #3: Enhanced Anti-Hallucination
### Problem
- Prompts could be stricter
- Temperature too high (0.1)
- Missing explicit "no general knowledge" rule
### Fix Applied
**Files Modified:**
- `app/rag/prompts.py` - Enhanced system prompt with 10 strict rules
- `app/config.py` - Set temperature to 0.0
**Changes:**
```python
# Temperature
TEMPERATURE: float = 0.0 # Zero for maximum determinism
# Enhanced Prompt
- Added rule: "DO NOT use general knowledge"
- Added rule: "Verify every claim"
- Added rule: "DO NOT extrapolate"
```
**Impact:** Significantly reduced hallucination risk.
---
## 🟠 Important Fix #4: Authentication Middleware Structure
### Problem
- No authentication/authorization
- Endpoints are public
### Fix Applied
**Files Created:**
- `app/middleware/auth.py` - Authentication middleware structure
**Note:** This is a **placeholder** that must be implemented with your actual auth system.
**TODO for Production:**
1. Integrate with JWT/OAuth provider
2. Verify tokens on every request
3. Extract tenant_id from token (don't trust client)
4. Implement RBAC if needed
---
## 🟠 Important Fix #5: Better Error Handling
### Problem
- Generic error messages
- Internal errors exposed to users
### Fix Applied
**Files Modified:**
- `app/main.py` - Enhanced error handling with structured responses
**Changes:**
- Specific error types (ValueError for config, generic for others)
- Error metadata for debugging
- User-friendly messages
---
## 📊 Configuration Updates
### Recommended Production Values
```env
# Chunking (optimized)
CHUNK_SIZE=600
CHUNK_OVERLAP=150
MIN_CHUNK_SIZE=100
# Retrieval (stricter)
TOP_K=6
SIMILARITY_THRESHOLD=0.40
# LLM (anti-hallucination)
TEMPERATURE=0.0
MAX_CONTEXT_TOKENS=3000
# Security
MAX_FILE_SIZE_MB=50
ALLOWED_ORIGINS=https://yourdomain.com,https://app.yourdomain.com
```
---
## ⚠️ Breaking Changes
### API Changes
All endpoints now require `tenant_id` parameter:
**Before:**
```json
{
"user_id": "user123",
"kb_id": "kb001",
"question": "How do I reset password?"
}
```
**After:**
```json
{
"tenant_id": "tenant_abc", // REQUIRED
"user_id": "user123",
"kb_id": "kb001",
"question": "How do I reset password?"
}
```
### Migration Required
Existing data in vector store needs `tenant_id` added. See `MIGRATION_GUIDE.md`.
---
## ✅ Testing Checklist
After applying fixes, test:
- [ ] Upload with tenant_id
- [ ] Chat with tenant_id
- [ ] Verify tenant A cannot access tenant B's data
- [ ] Test file size limits
- [ ] Test CORS restrictions
- [ ] Verify prompts refuse out-of-scope questions
