# Temperature Parameter Fix for GPT-5 Mini

## Problem

GPT-5 mini model does not support the `temperature` parameter when set to 0.0 or any non-default value. It only supports the default temperature value (1). This caused the following error:

```
Error code: 400 - {'error': {'message': "Unsupported value: 'temperature' does not support 0.0 with this model. Only the default (1) value is supported.", 'type': 'invalid_request_error', 'param': 'temperature', 'code': 'unsupported_value'}}
```

## Root Cause

The system was always passing a `temperature` parameter to the LLM, even when it was commented out in the configuration file. This happened because:

1. `LLMParametersConfig` had a default value of `temperature: float = 0`
2. `LLMRagConfig` had a default value of `temperature: float = 0.2`  
3. The LLM client always passed temperature to the model constructor

## Solution

Modified the code to only pass the `temperature` parameter when it's explicitly set in the configuration:

### 1. Changed Configuration Classes

**File: `service/config.py`**

- `LLMParametersConfig.temperature`: Changed from `float = 0` to `Optional[float] = None`
- `LLMRagConfig.temperature`: Changed from `float = 0.2` to `Optional[float] = None`

### 2. Updated Configuration Loading

**File: `service/config.py` - `get_llm_config()` method**

- Only include `temperature` in the config dict when it's explicitly set (not None)
- Added proper null checks for both new and legacy configuration formats

### 3. Modified LLM Client Construction

**File: `service/llm_client.py` - `_create_llm()` method**

- Changed to only pass `temperature` parameter when it exists in the config
- Removed hardcoded fallback temperature values
- Works for both OpenAI and Azure OpenAI providers

## Behavior

### Before Fix
- Temperature was always passed to the model (either 0, 0.2, or configured value)
- GPT-5 mini would reject requests with temperature != 1

### After Fix
- When `temperature` is commented out or not set: Parameter is not passed to model (uses model default)
- When `temperature` is explicitly set: Parameter is passed with the configured value
- GPT-5 mini works correctly as it uses its default temperature when none is specified

## Testing

Created comprehensive test script: `scripts/test_temperature_fix.py`

Test results show:
- ✅ When temperature not set: No temperature passed to model, API calls succeed
- ✅ When temperature set: Correct value passed to model  
- ✅ API stability: Multiple consecutive calls work correctly

## Configuration Examples

### No Temperature (Uses Model Default)
```yaml
# llm_prompt.yaml
parameters:
  # temperature: 0  # Commented out
  max_context_length: 100000
```

### Explicit Temperature
```yaml
# llm_prompt.yaml  
parameters:
  temperature: 0.7  # Will be passed to model
  max_context_length: 100000
```

## Backward Compatibility

- ✅ Existing configurations continue to work
- ✅ Legacy `config.yaml` LLM configurations still supported
- ✅ No breaking changes to API or behavior when temperature is explicitly set

## Files Modified

1. `service/config.py`
   - `LLMParametersConfig.temperature` → `Optional[float] = None`
   - `LLMRagConfig.temperature` → `Optional[float] = None`  
   - `get_llm_config()` → Only include temperature when set

2. `service/llm_client.py`
   - `_create_llm()` → Only pass temperature when in config

3. `scripts/test_temperature_fix.py` (New)
   - Comprehensive test suite for temperature handling