diff --git a/src/ClaudeDo.Data/Models/ModelRegistry.cs b/src/ClaudeDo.Data/Models/ModelRegistry.cs
index dd2f3cc1..8d3ea34f 100644
--- a/src/ClaudeDo.Data/Models/ModelRegistry.cs
+++ b/src/ClaudeDo.Data/Models/ModelRegistry.cs
@@ -5,7 +5,7 @@ public static class ModelRegistry
     public static readonly IReadOnlyList<string> Aliases = new[] { "sonnet", "opus", "haiku", "fable" };
 
     /// <summary>Model aliases ordered cheapest → most capable. Single source for prompt cost guidance.</summary>
-    public static readonly IReadOnlyList<string> ByCostAscending = new[] { "haiku", "sonnet", "opus" };
+    public static readonly IReadOnlyList<string> ByCostAscending = new[] { "haiku", "sonnet", "opus", "fable" };
 
     public const string DefaultAlias = "sonnet";
     public const string PlanningAlias = "opus";
diff --git a/tests/ClaudeDo.Data.Tests/ModelRegistryTests.cs b/tests/ClaudeDo.Data.Tests/ModelRegistryTests.cs
index f38382aa..5e6e6d72 100644
--- a/tests/ClaudeDo.Data.Tests/ModelRegistryTests.cs
+++ b/tests/ClaudeDo.Data.Tests/ModelRegistryTests.cs
@@ -29,9 +29,9 @@ public class ModelRegistryTests
     }
 
     [Fact]
-    public void ByCostAscending_is_haiku_sonnet_opus()
+    public void ByCostAscending_is_haiku_sonnet_opus_fable()
     {
-        Assert.Equal(new[] { "haiku", "sonnet", "opus" }, ModelRegistry.ByCostAscending);
+        Assert.Equal(new[] { "haiku", "sonnet", "opus", "fable" }, ModelRegistry.ByCostAscending);
     }
 
     [Theory]