diff --git a/tests/AnthropicClient.Tests/EndToEnd/AnthropicApiClientTests.cs b/tests/AnthropicClient.Tests/EndToEnd/AnthropicApiClientTests.cs
index 01cb07a..5b7a3cd 100644
--- a/tests/AnthropicClient.Tests/EndToEnd/AnthropicApiClientTests.cs
+++ b/tests/AnthropicClient.Tests/EndToEnd/AnthropicApiClientTests.cs
@@ -1,10 +1,10 @@
-using Xunit.Abstractions;
-using Xunit.Sdk;
-
 namespace AnthropicClient.Tests.EndToEnd;
 
 public class ClientTests(ConfigurationFixture configFixture) : EndToEndTest(configFixture)
 {
+  private string GetTestFilePath(string fileName) =>
+    Path.Combine(Directory.GetCurrentDirectory(), "Files", fileName);
+
   [Fact]
   public async Task CreateMessageAsync_WhenCalled_ItShouldReturnResponse()
   {
@@ -63,7 +63,7 @@ public class ClientTests(ConfigurationFixture configFixture) : EndToEndTest(conf
   [Fact]
   public async Task CreateMessageAsync_WhenImageIsSent_ItShouldReturnResponse()
   {
-    var imagePath = Path.Combine(Directory.GetCurrentDirectory(), "Files", "elephant.jpg");
+    var imagePath = GetTestFilePath("elephant.jpg");
     var mediaType = "image/jpeg";
     var bytes = await File.ReadAllBytesAsync(imagePath);
     var base64Data = Convert.ToBase64String(bytes);
@@ -96,4 +96,130 @@ public class ClientTests(ConfigurationFixture configFixture) : EndToEndTest(conf
 
     text.Should().Contain("elephant");
   }
+
+  [Fact]
+  public async Task CreateMessageAsync_WhenSystemMessagesContainCacheControl_ItShouldUseCache()
+  {
+    var httpClient = new HttpClient();
+    httpClient.DefaultRequestHeaders.Add("anthropic-beta", "prompt-caching-2024-07-31");
+
+    var client = CreateClient(httpClient);
+
+    var storyPath = GetTestFilePath("story.txt");
+    var storyText = await File.ReadAllTextAsync(storyPath);
+
+    var request = new MessageRequest(
+      model: AnthropicModels.Claude3Haiku,
+      systemMessages: [
+        new("You are a helpful assistant who can answer questions about the following text:"),
+        new(storyText, new EphemeralCacheControl())
+      ],
+      messages: [
+        new(MessageRole.User, [
+          new TextContent("Give me a one sentence summary of this story.")
+        ]),
+      ]
+    );
+
+    var resultOne = await client.CreateMessageAsync(request);
+
+    resultOne.IsSuccess.Should().BeTrue();
+    resultOne.Value.Should().BeOfType<MessageResponse>();
+    resultOne.Value.Content.Should().NotBeNullOrEmpty();
+    resultOne.Value.Usage.Should().Match<Usage>(u => u.CacheCreationInputTokens > 0 || u.CacheReadInputTokens > 0);
+
+    request.Messages.Add(new(MessageRole.Assistant, resultOne.Value.Content));
+    request.Messages.Add(new(MessageRole.User, [new TextContent("What is the main theme of this story?")]));
+
+    var resultTwo = await client.CreateMessageAsync(request);
+
+    resultTwo.IsSuccess.Should().BeTrue();
+    resultTwo.Value.Should().BeOfType<MessageResponse>();
+    resultTwo.Value.Content.Should().NotBeNullOrEmpty();
+    resultTwo.Value.Usage.CacheReadInputTokens.Should().BeGreaterThan(0);
+  }
+
+  [Fact]
+  public async Task CreateMessageAsync_WhenMessagesContainCacheControl_ItShouldUseCache()
+  {
+    var httpClient = new HttpClient();
+    httpClient.DefaultRequestHeaders.Add("anthropic-beta", "prompt-caching-2024-07-31");
+
+    var client = CreateClient(httpClient);
+
+    var storyPath = GetTestFilePath("story.txt");
+    var storyText = await File.ReadAllTextAsync(storyPath);
+
+    var request = new MessageRequest(
+      model: AnthropicModels.Claude3Haiku,
+      messages: [
+        new(MessageRole.User, [
+          new TextContent("Give me a one sentence summary of this story."),
+          new TextContent(storyText, new EphemeralCacheControl())
+        ]),
+      ]
+    );
+
+    var resultOne = await client.CreateMessageAsync(request);
+
+    resultOne.IsSuccess.Should().BeTrue();
+    resultOne.Value.Should().BeOfType<MessageResponse>();
+    resultOne.Value.Content.Should().NotBeNullOrEmpty();
+    resultOne.Value.Usage.Should().Match<Usage>(u => u.CacheCreationInputTokens > 0 || u.CacheReadInputTokens > 0);
+
+    request.Messages.Add(new(MessageRole.Assistant, resultOne.Value.Content));
+    request.Messages.Add(new(MessageRole.User, [new TextContent("What is the main theme of this story?")]));
+
+    var resultTwo = await client.CreateMessageAsync(request);
+
+    resultTwo.IsSuccess.Should().BeTrue();
+    resultTwo.Value.Should().BeOfType<MessageResponse>();
+    resultTwo.Value.Content.Should().NotBeNullOrEmpty();
+    resultTwo.Value.Usage.CacheReadInputTokens.Should().BeGreaterThan(0);
+  }
+
+  [Fact]
+  public async Task CreateMessageAsync_WhenToolsContainCacheControl_ItShouldUseCache()
+  {
+    var httpClient = new HttpClient();
+    httpClient.DefaultRequestHeaders.Add("anthropic-beta", "prompt-caching-2024-07-31");
+
+    var client = CreateClient(httpClient);
+
+    var func = (string ticker) => ticker;
+
+    var tools = Enumerable
+      .Range(0, 50)
+      .Select(i => Tool.CreateFromFunction($"tool-{i}", $"Tool {i}", func))
+      .ToList();
+
+    tools.Last().CacheControl = new EphemeralCacheControl();
+
+    var request = new MessageRequest(
+      model: AnthropicModels.Claude3Haiku,
+      messages: [
+        new(MessageRole.User, [
+          new TextContent("Hi could you tell me your name?"),
+        ]),
+      ],
+      tools: tools
+    );
+
+    var resultOne = await client.CreateMessageAsync(request);
+
+    resultOne.IsSuccess.Should().BeTrue();
+    resultOne.Value.Should().BeOfType<MessageResponse>();
+    resultOne.Value.Content.Should().NotBeNullOrEmpty();
+    resultOne.Value.Usage.Should().Match<Usage>(u => u.CacheCreationInputTokens > 0 || u.CacheReadInputTokens > 0);
+
+    request.Messages.Add(new(MessageRole.Assistant, resultOne.Value.Content));
+    request.Messages.Add(new(MessageRole.User, [new TextContent("Could you tell me the stock price for AAPL?")]));
+
+    var resultTwo = await client.CreateMessageAsync(request);
+
+    resultTwo.IsSuccess.Should().BeTrue();
+    resultTwo.Value.Should().BeOfType<MessageResponse>();
+    resultTwo.Value.Content.Should().NotBeNullOrEmpty();
+    resultTwo.Value.Usage.CacheReadInputTokens.Should().BeGreaterThan(0);
+  }
 }
\ No newline at end of file