diff --git a/.vscode/settings.json b/.vscode/settings.json
index 11a990d..b241574 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -17,5 +17,8 @@
     "targetdir",
     "typeof"
   ],
-  "dotnet.unitTests.runSettingsPath": "./tests/AnthropicClient.Tests/.runsettings"
+  "dotnet.unitTests.runSettingsPath": "./tests/AnthropicClient.Tests/.runsettings",
+  "search.exclude": {
+    "**/docs": true,
+  }
 }
\ No newline at end of file
diff --git a/tests/AnthropicClient.Tests/Unit/Models/CustomSourceTests.cs b/tests/AnthropicClient.Tests/Unit/Models/CustomSourceTests.cs
new file mode 100644
index 0000000..53d8379
--- /dev/null
+++ b/tests/AnthropicClient.Tests/Unit/Models/CustomSourceTests.cs
@@ -0,0 +1,35 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class CustomSourceTests
+{
+  [Fact]
+  public void Constructor_WhenCalled_ItShouldSetProperties()
+  {
+    var result = new CustomSource();
+
+    result.Content.Should().BeEmpty();
+    result.Type.Should().Be("content");
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithContent_ItShouldSetProperties()
+  {
+    var content = new List<TextContent>
+    {
+      new("Sample text")
+    };
+
+    var result = new CustomSource(content);
+
+    result.Content.Should().BeSameAs(content);
+    result.Type.Should().Be("content");
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullContent_ItShouldThrowArgumentNullException()
+  {
+    var act = () => new CustomSource(null!);
+
+    act.Should().Throw<ArgumentNullException>();
+  }
+}
\ No newline at end of file
diff --git a/tests/AnthropicClient.Tests/Unit/Models/DocumentContentTests.cs b/tests/AnthropicClient.Tests/Unit/Models/DocumentContentTests.cs
index 99525d5..1687bdb 100644
--- a/tests/AnthropicClient.Tests/Unit/Models/DocumentContentTests.cs
+++ b/tests/AnthropicClient.Tests/Unit/Models/DocumentContentTests.cs
@@ -87,6 +87,18 @@ public class DocumentContentTests : SerializationTest
     action.Should().Throw<ArgumentNullException>();
   }
 
+  [Fact]
+  public void Constructor_WhenCalledWithSourceAndCacheControl_ItShouldInitializeSourceAndCacheControl()
+  {
+    var source = new DocumentSource("application/pdf", "data");
+    var cacheControl = new EphemeralCacheControl();
+
+    var result = new DocumentContent(source, cacheControl);
+
+    result.Source.Should().BeSameAs(source);
+    result.CacheControl.Should().BeSameAs(cacheControl);
+  }
+
   [Fact]
   public void JsonSerialization_WhenSerialized_ItShouldHaveExpectedShape()
   {
diff --git a/tests/AnthropicClient.Tests/Unit/Models/PageLocationCitationTests.cs b/tests/AnthropicClient.Tests/Unit/Models/PageLocationCitationTests.cs
new file mode 100644
index 0000000..37cc3a4
--- /dev/null
+++ b/tests/AnthropicClient.Tests/Unit/Models/PageLocationCitationTests.cs
@@ -0,0 +1,17 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class PageLocationCitationTests
+{
+  [Fact]
+  public void Constructor_WhenCalled_ItShouldSetProperties()
+  {
+    var result = new PageLocationCitation();
+
+    result.Type.Should().Be("page_location");
+    result.CitedText.Should().BeEmpty();
+    result.DocumentIndex.Should().Be(0);
+    result.DocumentTitle.Should().BeEmpty();
+    result.StartPageNumber.Should().Be(0);
+    result.EndPageNumber.Should().Be(0);
+  }
+}
\ No newline at end of file
diff --git a/tests/AnthropicClient.Tests/Unit/Models/SourceTypeTests.cs b/tests/AnthropicClient.Tests/Unit/Models/SourceTypeTests.cs
new file mode 100644
index 0000000..1e091ab
--- /dev/null
+++ b/tests/AnthropicClient.Tests/Unit/Models/SourceTypeTests.cs
@@ -0,0 +1,22 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class SourceTypeTests
+{
+  [Fact]
+  public void Base64_WhenCalled_ItShouldReturnCorrectValue()
+  {
+    SourceType.Base64.Should().Be("base64");
+  }
+
+  [Fact]
+  public void Content_WhenCalled_ItShouldReturnCorrectValue()
+  {
+    SourceType.Content.Should().Be("content");
+  }
+
+  [Fact]
+  public void Text_WhenCalled_ItShouldReturnCorrectValue()
+  {
+    SourceType.Text.Should().Be("text");
+  }
+}
\ No newline at end of file
diff --git a/tests/AnthropicClient.Tests/Unit/Models/TextSourceTests.cs b/tests/AnthropicClient.Tests/Unit/Models/TextSourceTests.cs
new file mode 100644
index 0000000..eacdff3
--- /dev/null
+++ b/tests/AnthropicClient.Tests/Unit/Models/TextSourceTests.cs
@@ -0,0 +1,14 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class TextSourceTests
+{
+  [Fact]
+  public void Constructor_WhenCalled_ItShouldSetProperties()
+  {
+    var result = new TextSource("data");
+
+    result.Type.Should().Be("text");
+    result.MediaType.Should().Be("text/plain");
+    result.Data.Should().Be("data");
+  }
+}
\ No newline at end of file