.Net: Add Gemini usage metadata CachedContentTokenCount and ThoughtsTokenC… (#13208)

Add missing usage variables in GeminiMetadata class

### Motivation and Context

Gemini gives us CachedContentTokenCount and ThoughtsTokenCount to know
how much of cost have the request.
The total input as Gemini eyes is not only PromptTokenCount, but a sum
of these 3 variables.

### Description

Added CachedContentTokenCount and ThoughtsTokenCount variables, filled
by the response and add test.

**As I am beginner in C#, I can build and pass the test, also I can make
an .nupkg of the code changed, but I can't test on other projects, so
PLEASE check that before submitting changes. Thank you so much**

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [X ] The code builds clean without any errors or warnings
- [X ] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [X ] All unit tests pass, and I have added new tests where possible
- [ X] I didn't break anyone 😄

---------

Co-authored-by: Rodrigo <[email protected]>
Co-authored-by: Mark Wallace <[email protected]>
Co-authored-by: Roger Barreto <[email protected]>

Author: 4 people

dotnet/src/Connectors/Connectors.Google.UnitTests/Core/Gemini/Clients/GeminiChatGenerationTests.cs

@@ -164,6 +164,8 @@ public async Task ShouldReturnValidGeminiMetadataAsync()
         }
 
         Assert.Equal(testDataResponse.UsageMetadata!.PromptTokenCount, metadata.PromptTokenCount);
+        Assert.Equal(testDataResponse.UsageMetadata!.CachedContentTokenCount, metadata.CachedContentTokenCount);
+        Assert.Equal(testDataResponse.UsageMetadata!.ThoughtsTokenCount, metadata.ThoughtsTokenCount);
         Assert.Equal(testDataCandidate.TokenCount, metadata.CurrentCandidateTokenCount);
         Assert.Equal(testDataResponse.UsageMetadata.CandidatesTokenCount, metadata.CandidatesTokenCount);
         Assert.Equal(testDataResponse.UsageMetadata.TotalTokenCount, metadata.TotalTokenCount);
@@ -207,6 +209,8 @@ public async Task ShouldReturnValidDictionaryMetadataAsync()
         }
 
         Assert.Equal(testDataResponse.UsageMetadata!.PromptTokenCount, metadata[nameof(GeminiMetadata.PromptTokenCount)]);
+        Assert.Equal(testDataResponse.UsageMetadata!.CachedContentTokenCount, metadata[nameof(GeminiMetadata.CachedContentTokenCount)]);
+        Assert.Equal(testDataResponse.UsageMetadata!.ThoughtsTokenCount, metadata[nameof(GeminiMetadata.ThoughtsTokenCount)]);
         Assert.Equal(testDataCandidate.TokenCount, metadata[nameof(GeminiMetadata.CurrentCandidateTokenCount)]);
         Assert.Equal(testDataResponse.UsageMetadata.CandidatesTokenCount, metadata[nameof(GeminiMetadata.CandidatesTokenCount)]);
         Assert.Equal(testDataResponse.UsageMetadata.TotalTokenCount, metadata[nameof(GeminiMetadata.TotalTokenCount)]);

dotnet/src/Connectors/Connectors.Google.UnitTests/Core/Gemini/Clients/GeminiChatStreamingTests.cs

@@ -174,6 +174,8 @@ public async Task ShouldReturnValidGeminiMetadataAsync()
         }
 
         Assert.Equal(testDataResponse.UsageMetadata!.PromptTokenCount, metadata.PromptTokenCount);
+        Assert.Equal(testDataResponse.UsageMetadata!.CachedContentTokenCount, metadata.CachedContentTokenCount);
+        Assert.Equal(testDataResponse.UsageMetadata!.ThoughtsTokenCount, metadata.ThoughtsTokenCount);
         Assert.Equal(testDataCandidate.TokenCount, metadata.CurrentCandidateTokenCount);
         Assert.Equal(testDataResponse.UsageMetadata.CandidatesTokenCount, metadata.CandidatesTokenCount);
         Assert.Equal(testDataResponse.UsageMetadata.TotalTokenCount, metadata.TotalTokenCount);
@@ -218,6 +220,8 @@ public async Task ShouldReturnValidDictionaryMetadataAsync()
         }
 
         Assert.Equal(testDataResponse.UsageMetadata!.PromptTokenCount, metadata[nameof(GeminiMetadata.PromptTokenCount)]);
+        Assert.Equal(testDataResponse.UsageMetadata!.CachedContentTokenCount, metadata[nameof(GeminiMetadata.CachedContentTokenCount)]);
+        Assert.Equal(testDataResponse.UsageMetadata!.ThoughtsTokenCount, metadata[nameof(GeminiMetadata.ThoughtsTokenCount)]);
         Assert.Equal(testDataCandidate.TokenCount, metadata[nameof(GeminiMetadata.CurrentCandidateTokenCount)]);
         Assert.Equal(testDataResponse.UsageMetadata.CandidatesTokenCount, metadata[nameof(GeminiMetadata.CandidatesTokenCount)]);
         Assert.Equal(testDataResponse.UsageMetadata.TotalTokenCount, metadata[nameof(GeminiMetadata.TotalTokenCount)]);

dotnet/src/Connectors/Connectors.Google/Core/Gemini/Clients/GeminiChatCompletionClient.cs

@@ -791,6 +791,8 @@ private static GeminiMetadata GetResponseMetadata(
             FinishReason = candidate.FinishReason,
             Index = candidate.Index,
             PromptTokenCount = geminiResponse.UsageMetadata?.PromptTokenCount ?? 0,
+            CachedContentTokenCount = geminiResponse.UsageMetadata?.CachedContentTokenCount ?? 0,
+            ThoughtsTokenCount = geminiResponse.UsageMetadata?.ThoughtsTokenCount ?? 0,
             CurrentCandidateTokenCount = candidate.TokenCount,
             CandidatesTokenCount = geminiResponse.UsageMetadata?.CandidatesTokenCount ?? 0,
             TotalTokenCount = geminiResponse.UsageMetadata?.TotalTokenCount ?? 0,

dotnet/src/Connectors/Connectors.Google/Core/Gemini/Models/GeminiResponse.cs

@@ -39,6 +39,18 @@ internal sealed class UsageMetadataElement
         [JsonPropertyName("promptTokenCount")]
         public int PromptTokenCount { get; set; }
 
+        /// <summary>
+        /// Gets the number of cached content tokens used.
+        /// </summary>
+        [JsonPropertyName("cachedContentTokenCount")]
+        public int CachedContentTokenCount { get; set; }
+
+        /// <summary>
+        /// Gets the number of thoughts tokens used.
+        /// </summary>
+        [JsonPropertyName("thoughtsTokenCount")]
+        public int ThoughtsTokenCount { get; set; }
+
         /// <summary>
         /// Gets the count of used tokens for all candidates.
         /// </summary>

dotnet/src/Connectors/Connectors.Google/Models/Gemini/GeminiMetadata.cs

@@ -44,12 +44,21 @@ public int PromptTokenCount
     }
 
     /// <summary>
-    /// The count of token in the current candidate.
+    /// The count of cached content tokens.
     /// </summary>
-    public int CurrentCandidateTokenCount
+    public int CachedContentTokenCount
     {
-        get => (this.GetValueFromDictionary(nameof(this.CurrentCandidateTokenCount)) as int?) ?? 0;
-        internal init => this.SetValueInDictionary(value, nameof(this.CurrentCandidateTokenCount));
+        get => (this.GetValueFromDictionary(nameof(this.CachedContentTokenCount)) as int?) ?? 0;
+        internal init => this.SetValueInDictionary(value, nameof(this.CachedContentTokenCount));
+    }
+
+    /// <summary>
+    /// The count of thoughts tokens.
+    /// </summary>
+    public int ThoughtsTokenCount
+    {
+        get => (this.GetValueFromDictionary(nameof(this.ThoughtsTokenCount)) as int?) ?? 0;
+        internal init => this.SetValueInDictionary(value, nameof(this.ThoughtsTokenCount));
     }
 
     /// <summary>
@@ -61,6 +70,15 @@ public int CandidatesTokenCount
         internal init => this.SetValueInDictionary(value, nameof(this.CandidatesTokenCount));
     }
 
+    /// <summary>
+    /// The count of token in the current candidate.
+    /// </summary>
+    public int CurrentCandidateTokenCount
+    {
+        get => (this.GetValueFromDictionary(nameof(this.CurrentCandidateTokenCount)) as int?) ?? 0;
+        internal init => this.SetValueInDictionary(value, nameof(this.CurrentCandidateTokenCount));
+    }
+
     /// <summary>
     /// The total count of tokens (prompt + total candidates token count).
     /// </summary>

dotnet/src/IntegrationTests/Connectors/Google/Gemini/GeminiChatCompletionTests.cs

@@ -435,6 +435,8 @@ public async Task ChatGenerationReturnsUsedTokensAsync(ServiceType serviceType)
         Assert.True(geminiMetadata.CandidatesTokenCount > 0);
         Assert.True(geminiMetadata.PromptTokenCount > 0);
         Assert.True(geminiMetadata.CurrentCandidateTokenCount > 0);
+        Assert.True(geminiMetadata.CachedContentTokenCount > 0);
+        Assert.True(geminiMetadata.ThoughtsTokenCount > 0);
     }
 
     [RetryTheory]
@@ -459,10 +461,14 @@ public async Task ChatStreamingReturnsUsedTokensAsync(ServiceType serviceType)
         this.Output.WriteLine($"TotalTokenCount: {geminiMetadata.TotalTokenCount}");
         this.Output.WriteLine($"CandidatesTokenCount: {geminiMetadata.CandidatesTokenCount}");
         this.Output.WriteLine($"PromptTokenCount: {geminiMetadata.PromptTokenCount}");
+        this.Output.WriteLine($"CachedContentTokenCount: {geminiMetadata.CachedContentTokenCount}");
+        this.Output.WriteLine($"ThoughtsTokenCount: {geminiMetadata.ThoughtsTokenCount}");
         this.Output.WriteLine($"CurrentCandidateTokenCount: {geminiMetadata.CurrentCandidateTokenCount}");
         Assert.True(geminiMetadata.TotalTokenCount > 0);
         Assert.True(geminiMetadata.CandidatesTokenCount > 0);
         Assert.True(geminiMetadata.PromptTokenCount > 0);
+        Assert.True(geminiMetadata.CachedContentTokenCount > 0);
+        Assert.True(geminiMetadata.ThoughtsTokenCount > 0);
         Assert.True(geminiMetadata.CurrentCandidateTokenCount > 0);
     }