tghamm · tghamm · Oct 21, 2025 · Oct 21, 2025
diff --git a/Anthropic.SDK.Tests/SkillsTests.cs b/Anthropic.SDK.Tests/SkillsTests.cs
@@ -335,5 +335,13 @@ c is BashCodeExecutionToolResultContent bashCodeExecutionToolResultContent &&
                 bashCodeExecutionToolResultContent.Content is BashCodeExecutionOutputContent bashCodeExecutionOutputContent &&
                 !string.IsNullOrEmpty(bashCodeExecutionOutputContent.FileId)) != null);
         }
+
+        [TestMethod]
+        public async Task GetSkills()
+        {
+            var client = new AnthropicClient();
+            var skills = await client.Skills.ListSkillsAsync();
+            Assert.IsNotNull(skills);
+        }
     }
 }
diff --git a/Anthropic.SDK/AnthropicClient.cs b/Anthropic.SDK/AnthropicClient.cs
@@ -35,7 +35,7 @@ public class AnthropicClient : IDisposable
         /// <summary>
         /// Version of the Anthropic Beta API
         /// </summary>
-        public string AnthropicBetaVersion { get; set; } = "prompt-caching-2024-07-31,message-batches-2024-09-24,computer-use-2024-10-22,pdfs-2024-09-25,output-128k-2025-02-19,mcp-client-2025-04-04,code-execution-2025-08-25,skills-2025-10-02,files-api-2025-04-14";
+        public string AnthropicBetaVersion { get; set; } = "prompt-caching-2024-07-31,message-batches-2024-09-24,computer-use-2024-10-22,pdfs-2024-09-25,output-128k-2025-02-19,mcp-client-2025-04-04,code-execution-2025-08-25,files-api-2025-04-14";
 
         /// <summary>
         /// The API authentication information to use for API calls

diff --git a/Anthropic.SDK/BaseEndpoint.cs b/Anthropic.SDK/BaseEndpoint.cs
@@ -112,9 +112,9 @@ private static void TryParseHeaderValue<T>(HttpResponseMessage message, string h
         /// Makes an HTTP request and deserializes the response to the specified type without custom converters.
         /// </summary>
         protected async Task<T> HttpRequestSimple<T>(string url = null, HttpMethod verb = null,
-            object postData = null, CancellationToken ctx = default)
+            object postData = null, Dictionary<string, string> additionalHeaders = null, CancellationToken ctx = default)
         {
-            var response = await HttpRequestRaw(url, verb, postData, false, ctx).ConfigureAwait(false);
+            var response = await HttpRequestRaw(url, verb, postData, false, additionalHeaders, ctx).ConfigureAwait(false);
 
             // Optimization: Deserialize directly from HTTP response stream
             // Avoids intermediate string allocation and UTF8 encoding conversion
@@ -128,14 +128,14 @@ protected async Task<T> HttpRequestSimple<T>(string url = null, HttpMethod verb
             return res;
         }
 
-        /// <summary>
-        /// Makes a raw HTTP request and returns the response.
-        /// </summary>
-        protected async Task<HttpResponseMessage> HttpRequestRaw(string url = null, HttpMethod verb = null,
-            object postData = null, bool streaming = false, CancellationToken ctx = default)
-        {
-            return await HttpRequestRaw(url, verb, postData, streaming, null, ctx).ConfigureAwait(false);
-        }
+        ///// <summary>
+        ///// Makes a raw HTTP request and returns the response.
+        ///// </summary>
+        //protected async Task<HttpResponseMessage> HttpRequestRaw(string url = null, HttpMethod verb = null,
+        //    object postData = null, bool streaming = false, CancellationToken ctx = default)
+        //{
+        //    return await HttpRequestRaw(url, verb, postData, streaming, null, ctx).ConfigureAwait(false);
+        //}
 
         /// <summary>
         /// Makes a raw HTTP request and returns the response with additional headers.

diff --git a/Anthropic.SDK/Batches/BatchesEndpoint.cs b/Anthropic.SDK/Batches/BatchesEndpoint.cs
@@ -24,7 +24,7 @@ internal BatchesEndpoint(AnthropicClient client) : base(client) { }
         /// <param name="ctx"></param>
         public async Task<BatchResponse> CreateBatchAsync(List<BatchRequest> batches, CancellationToken ctx = default)
         {
-            var response = await HttpRequestSimple<BatchResponse>(Url, HttpMethod.Post, new { requests = batches }, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<BatchResponse>(Url, HttpMethod.Post, new { requests = batches }, null, ctx).ConfigureAwait(false);
 
             return response;
         }
@@ -36,7 +36,7 @@ public async Task<BatchResponse> CreateBatchAsync(List<BatchRequest> batches, Ca
         /// <param name="ctx"></param>
         public async Task<BatchResponse> CancelBatchAsync(string batchId, CancellationToken ctx = default)
         {
-            var response = await HttpRequestSimple<BatchResponse>(Url + $"/{batchId}/cancel", HttpMethod.Post, null, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<BatchResponse>(Url + $"/{batchId}/cancel", HttpMethod.Post, null, null, ctx).ConfigureAwait(false);
 
             return response;
         }
@@ -48,7 +48,7 @@ public async Task<BatchResponse> CancelBatchAsync(string batchId, CancellationTo
         /// <param name="ctx"></param>
         public async Task<BatchResponse> RetrieveBatchStatusAsync(string batchId, CancellationToken ctx = default)
         {
-            var response = await HttpRequestSimple<BatchResponse>(Url + $"/{batchId}", HttpMethod.Get, null, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<BatchResponse>(Url + $"/{batchId}", HttpMethod.Get, null, null, ctx).ConfigureAwait(false);
 
             return response;
         }
@@ -104,7 +104,7 @@ public async Task<BatchList> ListBatchesAsync(string beforeId = null, string aft
                 url += $"&after_id={afterId}";
             }
 
-            var response = await HttpRequestSimple<BatchList>(url, HttpMethod.Get, null, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<BatchList>(url, HttpMethod.Get, null, null, ctx).ConfigureAwait(false);
 
             return response;
         }

diff --git a/Anthropic.SDK/EndpointBase.cs b/Anthropic.SDK/EndpointBase.cs
@@ -109,7 +109,7 @@ protected async IAsyncEnumerable<BatchLine> HttpStreamingRequestBatches(string u
             HttpMethod verb = null,
             object postData = null, [EnumeratorCancellation] CancellationToken ctx = default)
         {
-            var response = await HttpRequestRaw(url, verb, postData, streaming: true, ctx).ConfigureAwait(false);
+            var response = await HttpRequestRaw(url, verb, postData, streaming: true, null, ctx).ConfigureAwait(false);
 #if NET6_0_OR_GREATER
             await using var stream = await response.Content.ReadAsStreamAsync(ctx).ConfigureAwait(false);
 #else
@@ -139,7 +139,7 @@ protected async IAsyncEnumerable<string> HttpStreamingRequestBatchesJsonl(string
             HttpMethod verb = null,
             object postData = null, [EnumeratorCancellation] CancellationToken ctx = default)
         {
-            var response = await HttpRequestRaw(url, verb, postData, streaming: true, ctx).ConfigureAwait(false);
+            var response = await HttpRequestRaw(url, verb, postData, streaming: true, null, ctx).ConfigureAwait(false);
 #if NET6_0_OR_GREATER
             await using var stream = await response.Content.ReadAsStreamAsync(ctx).ConfigureAwait(false);
 #else

diff --git a/Anthropic.SDK/Files/FilesEndpoint.cs b/Anthropic.SDK/Files/FilesEndpoint.cs
@@ -48,7 +48,7 @@ public async Task<FileListResponse> ListFilesAsync(
                 queryParams.Add($"after_id={afterId}");
 
             var queryString = "?" + string.Join("&", queryParams);
-            return await HttpRequestSimple<FileListResponse>($"{Endpoint}{queryString}", HttpMethod.Get, null, cancellationToken);
+            return await HttpRequestSimple<FileListResponse>($"{Url}{queryString}", HttpMethod.Get, null, null, cancellationToken);
         }
 
         /// <summary>
@@ -67,7 +67,7 @@ public async Task<FileMetadata> GetFileMetadataAsync(
                 throw new ArgumentNullException(nameof(fileId), "File ID cannot be null or empty.");
             }
 
-            return await HttpRequestSimple<FileMetadata>($"{Endpoint}/{fileId}", HttpMethod.Get, null, cancellationToken);
+            return await HttpRequestSimple<FileMetadata>($"{Url}/{fileId}", HttpMethod.Get, null, null, cancellationToken);
         }
 
         /// <summary>
@@ -86,7 +86,7 @@ public async Task<FileDeleteResponse> DeleteFileAsync(
                 throw new ArgumentNullException(nameof(fileId), "File ID cannot be null or empty.");
             }
 
-            return await HttpRequestSimple<FileDeleteResponse>($"{Endpoint}/{fileId}", HttpMethod.Delete, null, cancellationToken);
+            return await HttpRequestSimple<FileDeleteResponse>($"{Url}/{fileId}", HttpMethod.Delete, null, null, cancellationToken);
         }
 
         /// <summary>
@@ -157,7 +157,7 @@ public async Task<FileMetadata> UploadFileBytesAsync(byte[] fileBytes, string fi
             fileContent.Headers.ContentType = new MediaTypeHeaderValue(mimeType);
             content.Add(fileContent, "file", fileName);
 
-            var result = await HttpRequestSimple<FileMetadata>(Url, HttpMethod.Post, content, ctx).ConfigureAwait(false);
+            var result = await HttpRequestSimple<FileMetadata>(Url, HttpMethod.Post, content, null, ctx).ConfigureAwait(false);
 
             return result;
         }
@@ -194,7 +194,7 @@ public async Task<FileMetadata> UploadFileStreamAsync(Stream fileStream, string
             streamContent.Headers.ContentType = new MediaTypeHeaderValue(mimeType);
             content.Add(streamContent, "file", fileName);
 
-            var result = await HttpRequestSimple<FileMetadata>(Url, HttpMethod.Post, content, ctx).ConfigureAwait(false);
+            var result = await HttpRequestSimple<FileMetadata>(Url, HttpMethod.Post, content, null, ctx).ConfigureAwait(false);
 
             return result;
         }
@@ -215,7 +215,7 @@ public async Task<byte[]> DownloadFileAsync(string fileId, string outputPath = n
             }
 
             var url = $"{Url}/{fileId}/content";
-            var response = await HttpRequestRaw(url, HttpMethod.Get, null, streaming: false, ctx).ConfigureAwait(false);
+            var response = await HttpRequestRaw(url, HttpMethod.Get, null, streaming: false, null, ctx).ConfigureAwait(false);
 
 #if NET6_0_OR_GREATER
             var content = await response.Content.ReadAsByteArrayAsync(ctx).ConfigureAwait(false);
@@ -263,7 +263,7 @@ public async Task DownloadFileToStreamAsync(string fileId, Stream outputStream,
             }
 
             var url = $"{Url}/{fileId}/content";
-            var response = await HttpRequestRaw(url, HttpMethod.Get, null, streaming: true, ctx).ConfigureAwait(false);
+            var response = await HttpRequestRaw(url, HttpMethod.Get, null, streaming: true, null, ctx).ConfigureAwait(false);
 
 #if NET6_0_OR_GREATER
             await using var stream = await response.Content.ReadAsStreamAsync(ctx).ConfigureAwait(false);

diff --git a/Anthropic.SDK/Messaging/MessagesEndpoint.cs b/Anthropic.SDK/Messaging/MessagesEndpoint.cs
@@ -31,26 +31,7 @@ public async Task<MessageResponse> GetClaudeMessageAsync(MessageParameters param
             parameters.Stream = false;
 
             // Check if interleaved thinking is needed and add the header
-            Dictionary<string, string> additionalHeaders = null;
-            if (parameters.Thinking?.UseInterleavedThinking == true)
-            {
-                // Add the interleaved thinking beta header to the existing beta features
-                var existingBeta = Client.AnthropicBetaVersion;
-                var interleavedBeta = "interleaved-thinking-2025-05-14";
-
-                // Combine with existing beta features if they don't already include interleaved thinking
-                if (!existingBeta.Contains(interleavedBeta))
-                {
-                    var combinedBeta = string.IsNullOrWhiteSpace(existingBeta) 
-                        ? interleavedBeta 
-                        : $"{existingBeta},{interleavedBeta}";
-
-                    additionalHeaders = new Dictionary<string, string>
-                    {
-                        ["anthropic-beta"] = combinedBeta
-                    };
-                }
-            }
+            var additionalHeaders = SetAdditionalHeaders(parameters);
 
             var response = await HttpRequestMessages<MessageResponse>(Url, HttpMethod.Post, parameters, additionalHeaders, ctx).ConfigureAwait(false);
 
@@ -118,27 +99,7 @@ public async IAsyncEnumerable<MessageResponse> StreamClaudeMessageAsync(MessageP
 
             parameters.Stream = true;
 
-            // Check if interleaved thinking is needed and add the header
-            Dictionary<string, string> additionalHeaders = null;
-            if (parameters.Thinking?.UseInterleavedThinking == true)
-            {
-                // Add the interleaved thinking beta header to the existing beta features
-                var existingBeta = Client.AnthropicBetaVersion;
-                var interleavedBeta = "interleaved-thinking-2025-05-14";
-
-                // Combine with existing beta features if they don't already include interleaved thinking
-                if (!existingBeta.Contains(interleavedBeta))
-                {
-                    var combinedBeta = string.IsNullOrWhiteSpace(existingBeta) 
-                        ? interleavedBeta 
-                        : $"{existingBeta},{interleavedBeta}";
-
-                    additionalHeaders = new Dictionary<string, string>
-                    {
-                        ["anthropic-beta"] = combinedBeta
-                    };
-                }
-            }
+            var additionalHeaders = SetAdditionalHeaders(parameters);
 
             var toolCalls = new List<Function>();
             var arguments = string.Empty;
@@ -178,6 +139,51 @@ public async IAsyncEnumerable<MessageResponse> StreamClaudeMessageAsync(MessageP
                 yield return result;
             }
         }
+
+        private Dictionary<string, string> SetAdditionalHeaders(MessageParameters parameters)
+        {
+            // Check if interleaved thinking is needed and add the header
+            Dictionary<string, string> additionalHeaders = null;
+            if (parameters.Thinking?.UseInterleavedThinking == true)
+            {
+                // Add the interleaved thinking beta header to the existing beta features
+                var existingBeta = Client.AnthropicBetaVersion;
+                var interleavedBeta = "interleaved-thinking-2025-05-14";
+                // Combine with existing beta features if they don't already include interleaved thinking
+                if (!existingBeta.Contains(interleavedBeta))
+                {
+                    var combinedBeta = string.IsNullOrWhiteSpace(existingBeta)
+                        ? interleavedBeta
+                        : $"{existingBeta},{interleavedBeta}";
+
+                    additionalHeaders = new Dictionary<string, string>
+                    {
+                        ["anthropic-beta"] = combinedBeta
+                    };
+                }
+            }
+            if (parameters.Container != null)
+            {
+                if (additionalHeaders == null)
+                {
+                    additionalHeaders = new Dictionary<string, string>();
+                }
+                var existingBeta = Client.AnthropicBetaVersion;
+                var skillsBeta = "skills-2025-10-02";
+                // Combine with existing beta features if they don't already include skills
+                if (!existingBeta.Contains(skillsBeta))
+                {
+                    var combinedBeta = string.IsNullOrWhiteSpace(existingBeta)
+                        ? skillsBeta
+                        : $"{existingBeta},{skillsBeta}";
+                    additionalHeaders["anthropic-beta"] = combinedBeta;
+                }
+            }
+
+            return additionalHeaders;
+        }
+
+
         /// <summary>
         /// Makes a call to count the number of tokens in a request.
         /// </summary>

diff --git a/Anthropic.SDK/Models/ModelsEndpoint.cs b/Anthropic.SDK/Models/ModelsEndpoint.cs
@@ -40,7 +40,7 @@ public async Task<ModelList> ListModelsAsync(string beforeId = null, string afte
                 url += $"&after_id={afterId}";
             }
 
-            var response = await HttpRequestSimple<ModelList>(url, HttpMethod.Get, null, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<ModelList>(url, HttpMethod.Get, null, null, ctx).ConfigureAwait(false);
 
             return response;
         }
@@ -52,7 +52,7 @@ public async Task<ModelList> ListModelsAsync(string beforeId = null, string afte
         /// <param name="ctx"></param>
         public async Task<ModelResponse> GetModelAsync(string modelId, CancellationToken ctx = default)
         {
-            var response = await HttpRequestSimple<ModelResponse>(Url + $"/{modelId}", HttpMethod.Get, null, ctx).ConfigureAwait(false);
+            var response = await HttpRequestSimple<ModelResponse>(Url + $"/{modelId}", HttpMethod.Get, null, null, ctx).ConfigureAwait(false);
 
             return response;
         }