sciagent/docs/FIX_CHAT_ERROR.md

Fix Chat Assistant 500 Error

Issue

Getting 500 Internal Server Error when calling /api/v1/chat endpoint.

Root Causes

1. Model Name Mismatch ✅ FIXED

   • Code was using gemma3:27b but entrypoint pulls gemma3:270M
   • Fixed: Updated code to use gemma3:270M

2. Ollama Not Running

   • Ollama service might not be started in the container
   • Network connectivity issues

3. Model Not Available

   • Model might not be pulled yet
   • Model name incorrect

Solutions

Solution 1: Restart the Container

# Stop and restart the backend container
docker-compose down
docker-compose up -d be0

# Wait for Ollama to start (check logs)
docker-compose logs -f be0

Solution 2: Check Ollama Status

# Check if container is running
docker ps | grep be0

# Check Ollama inside container
docker exec be0 ollama list

# If Ollama is not running, start it
docker exec be0 ollama serve &

Solution 3: Pull the Model

# Pull the required model
docker exec be0 ollama pull gemma3:270M

# Verify it's available
docker exec be0 ollama list | grep gemma3

Solution 4: Test the Health Endpoint

# Check health endpoint (includes Ollama status)
curl http://localhost:4402/health

# Should show:
# {
#   "status": "healthy",
#   "ollama": {
#     "status": "connected",
#     "available_models": ["gemma3:270M", ...]
#   }
# }

Solution 5: Check Backend Logs

# View recent logs
docker-compose logs be0 | tail -50

# View ChatAssistant specific logs
tail -f be0/logs/ChatAssistant.log

Quick Fix Commands

# 1. Restart everything
docker-compose restart be0

# 2. Check Ollama
docker exec be0 ollama list

# 3. Test health
curl http://localhost:4402/health

# 4. Test chat endpoint
curl -X POST http://localhost:4402/api/v1/chat \
  -H "Content-Type: application/json" \
  -d '{"message": "Hello"}'

What Was Fixed

1. ✅ Model name changed from gemma3:27b to gemma3:270M
2. ✅ Added better error handling with specific error messages
3. ✅ Added Ollama connection check on initialization
4. ✅ Added health endpoint with Ollama status
5. ✅ Improved logging for debugging

Expected Behavior After Fix

1. Container starts and Ollama service runs
2. Model gemma3:270M is available
3. Health endpoint shows Ollama as "connected"
4. Chat endpoint returns 200 with AI response

If Still Not Working

1. Check container logs:

   docker-compose logs be0
   

2. Check if Ollama is accessible:

   docker exec be0 curl http://localhost:11434/api/tags
   

3. Manually start Ollama:

   docker exec -d be0 ollama serve
   sleep 2
   docker exec be0 ollama list
   

4. Rebuild container:

   docker-compose down
   docker-compose build be0
   docker-compose up be0