feat: Populate per-modality prompt token count in embedding responses for gemini-embedding-2

PiperOrigin-RevId: 940552765

Author: speedstorm1

Google.GenAI/Models.cs

@@ -308,6 +308,11 @@ internal JsonNode ContentEmbeddingStatisticsFromVertex(JsonNode fromObject,
                               Common.GetValueByPath(fromObject, new string[] { "token_count" }));
       }
 
+      if (Common.GetValueByPath(fromObject, new string[] { "tokensDetails" }) != null) {
+        Common.SetValueByPath(toObject, new string[] { "tokensDetails" },
+                              Common.GetValueByPath(fromObject, new string[] { "tokensDetails" }));
+      }
+
       return toObject;
     }
 
@@ -1059,6 +1064,10 @@ internal JsonNode EmbedContentResponseFromVertex(JsonNode fromObject, JsonObject
             stats.Add("token_count",
                       JsonNode.Parse(usageMetadata["promptTokenCount"].ToJsonString()));
           }
+          if (usageMetadata != null && usageMetadata["promptTokensDetails"] != null) {
+            stats.Add("tokensDetails",
+                      JsonNode.Parse(usageMetadata["promptTokensDetails"].ToJsonString()));
+          }
           if (truncated != null) {
             stats.Add("truncated", JsonNode.Parse(truncated.ToJsonString()));
           }

Google.GenAI/types/ContentEmbeddingStatistics.cs

@@ -45,6 +45,17 @@ public double
             get; set;
           }
 
+    /// <summary>
+    /// Gemini Enterprise Agent Platform only. List of modalities and their token count for the
+    /// input content.
+    /// </summary>
+    [JsonPropertyName("tokensDetails")]
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public List<ModalityTokenCount>
+        ? TokensDetails {
+            get; set;
+          }
+
     /// <summary>
     /// Deserializes a JSON string to a ContentEmbeddingStatistics object.
     /// </summary>