managing-apps/assets/documentation/MCP-Configuration-Models.md

MCP LLM Model Configuration

Overview

All LLM provider models are now configured exclusively through appsettings.json - no hardcoded values in the code. This allows you to easily change models without recompiling the application.

Configuration Location

All model settings are in: src/Managing.Api/appsettings.json

{
  "Llm": {
    "Gemini": {
      "ApiKey": "",  // Add your key here or via user secrets
      "DefaultModel": "gemini-3-flash-preview"
    },
    "OpenAI": {
      "ApiKey": "",
      "DefaultModel": "gpt-4o"
    },
    "Claude": {
      "ApiKey": "",
      "DefaultModel": "claude-haiku-4-5-20251001"
    }
  }
}

Current Models (from appsettings.json)

• Gemini: gemini-3-flash-preview
• OpenAI: gpt-4o
• Claude: claude-haiku-4-5-20251001

Fallback Models (in code)

If DefaultModel is not specified in configuration, the providers use these fallback models:

• Gemini: gemini-2.0-flash-exp
• OpenAI: gpt-4o
• Claude: claude-3-5-sonnet-20241022

How It Works

1. Configuration Reading

When the application starts, LlmService reads the model configuration:

var geminiModel = _configuration["Llm:Gemini:DefaultModel"];
var openaiModel = _configuration["Llm:OpenAI:DefaultModel"];
var claudeModel = _configuration["Llm:Claude:DefaultModel"];

2. Provider Initialization

Each provider is initialized with the configured model:

_providers["gemini"] = new GeminiProvider(geminiApiKey, geminiModel, httpClientFactory, _logger);
_providers["openai"] = new OpenAiProvider(openaiApiKey, openaiModel, httpClientFactory, _logger);
_providers["claude"] = new ClaudeProvider(claudeApiKey, claudeModel, httpClientFactory, _logger);

3. Model Usage

The provider uses the configured model for all API calls:

public async Task<LlmChatResponse> ChatAsync(LlmChatRequest request)
{
    var model = _defaultModel; // From configuration
    var url = $"{BaseUrl}/models/{model}:generateContent?key={_apiKey}";
    // ...
}

Changing Models

Method 1: Edit appsettings.json

{
  "Llm": {
    "Claude": {
      "DefaultModel": "claude-3-5-sonnet-20241022"  // Change to Sonnet
    }
  }
}

Method 2: Environment Variables

export Llm__Claude__DefaultModel="claude-3-5-sonnet-20241022"

Method 3: User Secrets (Development)

cd src/Managing.Api
dotnet user-secrets set "Llm:Claude:DefaultModel" "claude-3-5-sonnet-20241022"

Available Models

Gemini Models

• gemini-2.0-flash-exp - Latest Flash (experimental)
• gemini-3-flash-preview - Flash preview
• gemini-1.5-pro - Pro model
• gemini-1.5-flash - Fast and efficient

OpenAI Models

• gpt-4o - GPT-4 Optimized (recommended)
• gpt-4o-mini - Smaller, faster
• gpt-4-turbo - GPT-4 Turbo
• gpt-3.5-turbo - Cheaper, faster

Claude Models

• claude-haiku-4-5-20251001 - Haiku 4.5 (fastest, cheapest)
• claude-3-5-sonnet-20241022 - Sonnet 3.5 (balanced, recommended)
• claude-3-opus-20240229 - Opus (most capable)
• claude-3-sonnet-20240229 - Sonnet 3
• claude-3-haiku-20240307 - Haiku 3

Model Selection Guide

For Development/Testing

• Gemini: gemini-2.0-flash-exp (free tier)
• Claude: claude-haiku-4-5-20251001 (cheapest)
• OpenAI: gpt-4o-mini (cheapest)

For Production (Balanced)

• Claude: claude-3-5-sonnet-20241022 ✅ Recommended
• OpenAI: gpt-4o
• Gemini: gemini-1.5-pro

For Maximum Capability

• Claude: claude-3-opus-20240229 (best reasoning)
• OpenAI: gpt-4-turbo
• Gemini: gemini-1.5-pro

For Speed/Cost Efficiency

• Claude: claude-haiku-4-5-20251001
• OpenAI: gpt-4o-mini
• Gemini: gemini-2.0-flash-exp

Cost Comparison (Approximate)

Claude

• Haiku 4.5: ~$0.50 per 1M tokens (cheapest)
• Sonnet 3.5: ~$9 per 1M tokens (recommended)
• Opus: ~$45 per 1M tokens (most expensive)

OpenAI

• GPT-4o-mini: ~$0.30 per 1M tokens
• GPT-4o: ~$10 per 1M tokens
• GPT-4-turbo: ~$30 per 1M tokens

Gemini

• Free tier: 15 requests/minute (development)
• Paid: ~$0.50 per 1M tokens

Logging

When providers are initialized, you'll see log messages indicating which model is being used:

[Information] Gemini provider initialized with model: gemini-3-flash-preview
[Information] OpenAI provider initialized with model: gpt-4o
[Information] Claude provider initialized with model: claude-haiku-4-5-20251001

If no model is configured, it will show:

[Information] Gemini provider initialized with model: default

And the fallback model will be used.

Best Practices

1. Use environment variables for production to keep configuration flexible
2. Test with cheaper models during development
3. Monitor costs in provider dashboards
4. Update models as new versions are released
5. Document changes when switching models for your team

Example Configurations

Development (Cost-Optimized)

{
  "Llm": {
    "Claude": {
      "ApiKey": "your-key",
      "DefaultModel": "claude-haiku-4-5-20251001"
    }
  }
}

Production (Balanced)

{
  "Llm": {
    "Claude": {
      "ApiKey": "your-key",
      "DefaultModel": "claude-3-5-sonnet-20241022"
    }
  }
}

High-Performance (Maximum Capability)

{
  "Llm": {
    "Claude": {
      "ApiKey": "your-key",
      "DefaultModel": "claude-3-opus-20240229"
    }
  }
}

Verification

To verify which model is being used:

1. Check application logs on startup
2. Look for provider initialization messages
3. Check LLM response metadata (includes model name)
4. Monitor provider dashboards for API usage

Troubleshooting

Model not found error

Issue: "Model not found" or "Invalid model name"

Solution:

1. Verify model name spelling in appsettings.json
2. Check provider documentation for available models
3. Ensure model is available in your region/tier
4. Try removing DefaultModel to use the fallback

Wrong model being used

Issue: Application uses fallback instead of configured model

Solution:

1. Check configuration path: Llm:ProviderName:DefaultModel
2. Verify no typos in JSON (case-sensitive)
3. Restart application after configuration changes
4. Check logs for which model was loaded

Configuration not loading

Issue: Changes to appsettings.json not taking effect

Solution:

1. Restart the application
2. Clear build artifacts: dotnet clean
3. Check file is in correct location: src/Managing.Api/appsettings.json
4. Verify JSON syntax is valid

Summary

✅ All models configured in appsettings.json ✅ No hardcoded model names in code ✅ Easy to change without recompiling ✅ Fallback models in case of missing configuration ✅ Full flexibility for different environments ✅ Logged on startup for verification

This design allows maximum flexibility while maintaining sensible defaults!