feat: Add Google Gemini provider

src/Cellm/AddIn/CellmAddIn.cs

@@ -7,6 +7,7 @@
 using Cellm.Models.Providers.Anthropic;
 using Cellm.Models.Providers.Cellm;
 using Cellm.Models.Providers.DeepSeek;
+using Cellm.Models.Providers.Google;
 using Cellm.Models.Providers.Mistral;
 using Cellm.Models.Providers.Ollama;
 using Cellm.Models.Providers.OpenAi;
@@ -68,6 +69,7 @@ private static ServiceCollection ConfigureServices(ServiceCollection services)
             .Configure<AccountConfiguration>(configuration.GetRequiredSection(nameof(AccountConfiguration)))
             .Configure<AnthropicConfiguration>(configuration.GetRequiredSection(nameof(AnthropicConfiguration)))
             .Configure<CellmConfiguration>(configuration.GetRequiredSection(nameof(CellmConfiguration)))
+            .Configure<GoogleGeminiConfiguration>(configuration.GetRequiredSection(nameof(GoogleGeminiConfiguration)))
             .Configure<DeepSeekConfiguration>(configuration.GetRequiredSection(nameof(DeepSeekConfiguration)))
             .Configure<CellmAddInConfiguration>(configuration.GetRequiredSection(nameof(CellmAddInConfiguration)))
             .Configure<MistralConfiguration>(configuration.GetRequiredSection(nameof(MistralConfiguration)))
@@ -133,6 +135,7 @@ private static ServiceCollection ConfigureServices(ServiceCollection services)
             .AddAnthropicChatClient()
             .AddCellmChatClient()
             .AddDeepSeekChatClient()
+            .AddGoogleGeminiChatClient()
             .AddMistralChatClient()
             .AddOllamaChatClient()
             .AddOpenAiChatClient()

src/Cellm/AddIn/CellmFunctions.cs

@@ -174,7 +174,6 @@ internal static async Task<object> GetResponseAsync(Arguments arguments, Stopwat
             logger.LogInformation("Sending prompt to {}/{} ({}) ... Done (elapsed time: {}ms, request time: {}ms)", arguments.Provider, arguments.Model, callerCoordinates, wallClock.ElapsedMilliseconds, requestClock.ElapsedMilliseconds);
 
             return assistantMessage;
-
         }
         // Short-circuit if any cells were found to be #GETTING_DATA or contain other errors during cell parsing. 
         // Excel will re-trigger this function (or already has) when inputs are updated with realized values.

src/Cellm/AddIn/UserInterface/Ribbon/RibbonModelGroup.cs

@@ -57,11 +57,12 @@ private class ProviderItem
     private readonly Dictionary<int, ProviderItem> _providerItems = new()
     {
         [0] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.Anthropic)}", Image = $"{ResourcesBasePath}/anthropic.png", Label = nameof(Provider.Anthropic), Entitlement = Entitlement.EnableAnthropicProvider },
-        [1] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.DeepSeek)}", Image = $"{ResourcesBasePath}/deepseek.png", Label = nameof(Provider.DeepSeek), Entitlement = Entitlement.EnableDeepSeekProvider },
-        [2] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.Mistral)}", Image = $"{ResourcesBasePath}/mistral.png", Label = nameof(Provider.Mistral), Entitlement = Entitlement.EnableMistralProvider },
-        [3] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.Ollama)}", Image = $"{ResourcesBasePath}/ollama.png", Label = nameof(Provider.Ollama), Entitlement = Entitlement.EnableOllamaProvider },
-        [4] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.OpenAi)}", Image = $"{ResourcesBasePath}/openai.png", Label = nameof(Provider.OpenAi), Entitlement = Entitlement.EnableOpenAiProvider },
-        [5] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.OpenAiCompatible)}", Image = $"{ResourcesBasePath}/openai.png", Label = nameof(Provider.OpenAiCompatible) }
+        [1] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.GoogleGemini)}", Image = $"{ResourcesBasePath}/google.png", Label = nameof(Provider.GoogleGemini), Entitlement = Entitlement.EnableGoogleGeminiProvider },
+        [2] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.DeepSeek)}", Image = $"{ResourcesBasePath}/deepseek.png", Label = nameof(Provider.DeepSeek), Entitlement = Entitlement.EnableDeepSeekProvider },
+        [3] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.Mistral)}", Image = $"{ResourcesBasePath}/mistral.png", Label = nameof(Provider.Mistral), Entitlement = Entitlement.EnableMistralProvider },
+        [4] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.Ollama)}", Image = $"{ResourcesBasePath}/ollama.png", Label = nameof(Provider.Ollama), Entitlement = Entitlement.EnableOllamaProvider },
+        [5] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.OpenAi)}", Image = $"{ResourcesBasePath}/openai.png", Label = nameof(Provider.OpenAi), Entitlement = Entitlement.EnableOpenAiProvider },
+        [6] = new ProviderItem { Id = $"{nameof(Provider)}.{nameof(Provider.OpenAiCompatible)}", Image = $"{ResourcesBasePath}/openai.png", Label = nameof(Provider.OpenAiCompatible) }
     };
 
     internal int _selectedProviderIndex = 3; // Default to Ollama

src/Cellm/Models/Providers/Google/GoogleGeminiConfiguration.cs

@@ -0,0 +1,16 @@
+namespace Cellm.Models.Providers.Google;
+
+internal class GoogleGeminiConfiguration
+{
+    public Uri BaseAddress => new("https://generativelanguage.googleapis.com/v1beta/openai/");
+
+    public string DefaultModel { get; init; } = string.Empty;
+
+    public string ApiKey { get; init; } = string.Empty;
+
+    public string SmallModel { get; init; } = string.Empty;
+
+    public string MediumModel { get; init; } = string.Empty;
+
+    public string LargeModel { get; init; } = string.Empty;
+}

src/Cellm/Models/Providers/Provider.cs

@@ -5,6 +5,7 @@ public enum Provider
     Anthropic,
     Cellm,
     DeepSeek,
+    GoogleGemini,
     Mistral,
     Ollama,
     OpenAi,

src/Cellm/Models/ServiceCollectionExtensions.cs

@@ -32,6 +32,7 @@
 using Cellm.Models.Providers.Anthropic;
 using Cellm.Models.Providers.Cellm;
 using Cellm.Models.Providers.DeepSeek;
+using Cellm.Models.Providers.Google;
 using Cellm.Models.Providers.Mistral;
 using Cellm.Models.Providers.Ollama;
 using Cellm.Models.Providers.OpenAi;
@@ -211,6 +212,32 @@ public static IServiceCollection AddDeepSeekChatClient(this IServiceCollection s
         return services;
     }
 
+    public static IServiceCollection AddGoogleGeminiChatClient(this IServiceCollection services)
+    {
+        services
+            .AddKeyedChatClient(Provider.GoogleGemini, serviceProvider =>
+            {
+                var account = serviceProvider.GetRequiredService<Account>();
+                account.RequireEntitlement(Entitlement.EnableGoogleGeminiProvider);
+
+                var googleGeminiConfiguration = serviceProvider.GetRequiredService<IOptionsMonitor<GoogleGeminiConfiguration>>();
+                var resilientHttpClient = serviceProvider.GetKeyedService<HttpClient>("ResilientHttpClient") ?? throw new NullReferenceException("ResilientHttpClient");
+
+                var openAiClient = new OpenAIClient(
+                    new ApiKeyCredential(googleGeminiConfiguration.CurrentValue.ApiKey),
+                    new OpenAIClientOptions
+                    {
+                        Transport = new HttpClientPipelineTransport(resilientHttpClient),
+                        Endpoint = googleGeminiConfiguration.CurrentValue.BaseAddress
+                    });
+
+                return openAiClient.GetChatClient(googleGeminiConfiguration.CurrentValue.DefaultModel).AsIChatClient();
+            }, ServiceLifetime.Transient)
+            .UseFunctionInvocation();
+
+        return services;
+    }
+
     public static IServiceCollection AddMistralChatClient(this IServiceCollection services)
     {
         services

src/Cellm/Users/Entitlement.cs

@@ -5,11 +5,12 @@ public enum Entitlement
     EnableAnthropicProvider,
     EnableCellmProvider,
     EnableDeepSeekProvider,
+    EnableGoogleGeminiProvider,
     EnableMistralProvider,
     EnableOllamaProvider,
     EnableOpenAiProvider,
     EnableOpenAiCompatibleProvider,
     EnableModelContextProtocol,
-    DisableTelemetry
+    DisableTelemetry,
 }
 

src/Cellm/appsettings.json

@@ -6,7 +6,7 @@
     },
     "AnthropicConfiguration": {
         "DefaultModel": "claude-3-7-sonnet-latest",
-        "ApiKey": "API_KEY",
+        "ApiKey": "",
         "SmallModel": "claude-3-5-haiku-latest",
         "MediumModel": "claude-3-7-sonnet-latest",
         "LargeModel": "claude-3-opus-latest"
@@ -33,18 +33,25 @@
     },
     "DeepSeekConfiguration": {
         "DefaultModel": "deepseek-chat",
-        "ApiKey": "API_KEY",
+        "ApiKey": "",
         "MediumModel": "deepseek-chat",
         "LargeModel": "deepseek-reasoner"
     },
+    "GoogleGeminiConfiguration": {
+        "DefaultModel": "gemini-2.5-flash-preview-05-20",
+        "ApiKey": "",
+        "MediumModel": "gemini-2.5-flash-preview-05-20",
+        "LargeModel": "gemini-2.5-pro-preview-06-05"
+    },
     "Logging": {
         "LogLevel": {
-            "Default": "Information"
+            "Default": "Information",
+            "Microsoft.Extensions.Http.Logging.HttpClientLogger": "Warning"
         }
     },
     "MistralConfiguration": {
         "DefaultModel": "mistral-small-latest",
-        "ApiKey": "API_KEY",
+        "ApiKey": "",
         "SmallModel": "mistral-small-latest",
         "LargeModel": "mistral-large-latest"
     },
@@ -61,15 +68,15 @@
     },
     "OpenAiConfiguration": {
         "DefaultModel": "gpt-4.1-mini",
-        "ApiKey": "API_KEY",
+        "ApiKey": "",
         "SmallModel": "gpt-4.1-mini",
         "MediumModel": "gpt-4.1",
         "LargeModel": "o4-mini"
     },
     "OpenAiCompatibleConfiguration": {
         "BaseAddress": "https://api.openai.com/v1",
         "DefaultModel": "gpt-4o-mini",
-        "ApiKey": "API_KEY"
+        "ApiKey": ""
     },
     "ModelContextProtocolConfiguration": {
         "StdioServers": [