diff --git a/GFramework.SourceGenerators.Tests/Cqrs/CqrsHandlerRegistryGeneratorTests.cs b/GFramework.SourceGenerators.Tests/Cqrs/CqrsHandlerRegistryGeneratorTests.cs
index ce391657..d5653dc3 100644
--- a/GFramework.SourceGenerators.Tests/Cqrs/CqrsHandlerRegistryGeneratorTests.cs
+++ b/GFramework.SourceGenerators.Tests/Cqrs/CqrsHandlerRegistryGeneratorTests.cs
@@ -2870,6 +2870,50 @@ public class CqrsHandlerRegistryGeneratorTests
         });
     }
 
+    /// <summary>
+    ///     验证当 runtime 同时支持直接 <see cref="Type" /> 与字符串 fallback 元数据、但不允许多个 fallback 特性实例时，
+    ///     mixed 场景会整体回退到单个字符串特性，避免生成会违反 runtime attribute usage 的多实例元数据。
+    /// </summary>
+    [Test]
+    public void
+        Emits_String_Fallback_Metadata_For_Mixed_Fallback_When_Runtime_Disallows_Multiple_Fallback_Attributes()
+    {
+        var source = ReplaceAttributeUsageForType(
+            AssemblyLevelMixedFallbackMetadataSource,
+            "CqrsReflectionFallbackAttribute",
+            "[AttributeUsage(AttributeTargets.Assembly)]");
+        var execution = ExecuteGenerator(
+            source,
+            allowUnsafe: true);
+        var inputCompilationErrors = execution.InputCompilationDiagnostics
+            .Where(static diagnostic => diagnostic.Severity == DiagnosticSeverity.Error)
+            .ToArray();
+        var generatedCompilationErrors = execution.GeneratedCompilationDiagnostics
+            .Where(static diagnostic => diagnostic.Severity == DiagnosticSeverity.Error)
+            .ToArray();
+        var generatorErrors = execution.GeneratorDiagnostics
+            .Where(static diagnostic => diagnostic.Severity == DiagnosticSeverity.Error)
+            .ToArray();
+        Assert.Multiple(() =>
+        {
+            Assert.That(inputCompilationErrors.Select(static diagnostic => diagnostic.Id), Does.Contain("CS0306"));
+            Assert.That(generatedCompilationErrors, Is.Empty);
+            Assert.That(generatorErrors, Is.Empty);
+            Assert.That(execution.GeneratedSources, Has.Length.EqualTo(1));
+            var generatedSource = execution.GeneratedSources[0].content;
+            Assert.That(
+                generatedSource,
+                Does.Contain(
+                    "[assembly: global::GFramework.Cqrs.CqrsReflectionFallbackAttribute(\"TestApp.Container+AlphaHandler\", \"TestApp.Container+BetaHandler\")]"));
+            Assert.That(generatedSource, Does.Not.Contain("CqrsReflectionFallbackAttribute(typeof("));
+            Assert.That(
+                CountOccurrences(
+                    generatedSource,
+                    "[assembly: global::GFramework.Cqrs.CqrsReflectionFallbackAttribute"),
+                Is.EqualTo(1));
+        });
+    }
+
     /// <summary>
     ///     验证当 runtime 暴露 request invoker provider 契约时，生成器会让 generated registry 同时发射
     ///     request invoker 描述符与对应的开放静态 invoker 方法。
@@ -3425,6 +3469,47 @@ public class CqrsHandlerRegistryGeneratorTests
         return !char.IsLetterOrDigit(character) && character != '_';
     }
 
+    /// <summary>
+    ///     替换指定测试类型紧邻的 <c>AttributeUsage</c> 声明，用于构造 runtime contract 的 attribute usage 变体。
+    /// </summary>
+    /// <param name="source">原始测试源码。</param>
+    /// <param name="typeName">需要定位的类型名。</param>
+    /// <param name="replacementAttributeUsage">替换后的完整 <c>AttributeUsage</c> 声明。</param>
+    /// <returns>完成 attribute usage 替换后的源码。</returns>
+    private static string ReplaceAttributeUsageForType(
+        string source,
+        string typeName,
+        string replacementAttributeUsage)
+    {
+        ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(typeName);
+        ArgumentNullException.ThrowIfNull(replacementAttributeUsage);
+
+        var typeIndex = source.IndexOf($"public sealed class {typeName}", StringComparison.Ordinal);
+        if (typeIndex < 0)
+        {
+            throw new InvalidOperationException("The requested type declaration was not found in the generator test input.");
+        }
+
+        const string attributeUsagePrefix = "[AttributeUsage(";
+        var attributeUsageStartIndex = source.LastIndexOf(attributeUsagePrefix, typeIndex, StringComparison.Ordinal);
+        if (attributeUsageStartIndex < 0)
+        {
+            throw new InvalidOperationException("The requested AttributeUsage declaration was not found in the generator test input.");
+        }
+
+        var attributeUsageEndIndex = source.IndexOf(']', attributeUsageStartIndex);
+        if (attributeUsageEndIndex < 0 || attributeUsageEndIndex > typeIndex)
+        {
+            throw new InvalidOperationException("The requested AttributeUsage declaration is malformed.");
+        }
+
+        return source.Remove(
+                attributeUsageStartIndex,
+                attributeUsageEndIndex - attributeUsageStartIndex + 1)
+            .Insert(attributeUsageStartIndex, replacementAttributeUsage);
+    }
+
     /// <summary>
     ///     统计生成源码中某个固定片段的出现次数，用于锁定程序集级 fallback 特性的发射个数。
     /// </summary>
diff --git a/ai-plan/public/cqrs-rewrite/todos/cqrs-rewrite-migration-tracking.md b/ai-plan/public/cqrs-rewrite/todos/cqrs-rewrite-migration-tracking.md
index 1ceb403a..dddc1be6 100644
--- a/ai-plan/public/cqrs-rewrite/todos/cqrs-rewrite-migration-tracking.md
+++ b/ai-plan/public/cqrs-rewrite/todos/cqrs-rewrite-migration-tracking.md
@@ -7,13 +7,14 @@ CQRS 迁移与收敛。
 
 ## 当前恢复点
 
-- 恢复点编号：`CQRS-REWRITE-RP-077`
+- 恢复点编号：`CQRS-REWRITE-RP-078`
 - 当前阶段：`Phase 8`
 - 当前 PR 锚点：`PR #307`
 - 当前结论：
   - `GFramework.Cqrs` 已完成对外部 `Mediator` 的生产级替代，当前主线已从“是否可替代”转向“仓库内部收口与能力深化顺序”
-  - `dispatch/invoker` 生成前移已扩展到 request / stream 路径，当前 `RP-077` 已补齐 request invoker provider gate 与 stream gate 对称的 descriptor / descriptor entry runtime 合同回归
-  - `ai-plan` active 入口现以 `PR #307` 和 `RP-077` 为唯一权威恢复锚点；更早 PR 与阶段细节均以下方归档为准
+  - `dispatch/invoker` 生成前移已扩展到 request / stream 路径，`RP-077` 已补齐 request invoker provider gate 与 stream gate 对称的 descriptor / descriptor entry runtime 合同回归
+  - 当前 `RP-078` 已补齐 mixed fallback metadata 在 runtime 不允许多个 fallback attribute 实例时的单字符串 attribute 回退回归
+  - `ai-plan` active 入口现以 `PR #307` 和 `RP-078` 为唯一权威恢复锚点；更早 PR 与阶段细节均以下方归档为准
 
 ## 当前活跃事实
 
@@ -44,11 +45,18 @@ CQRS 迁移与收敛。
 - `python3 scripts/license-header.py --check`
   - 结果：通过
   - 备注：当前 WSL worktree 需要显式绑定 `GIT_DIR` / `GIT_WORK_TREE` 后运行，避免脚本内部 plain `git ls-files` 误判仓库上下文
+- `dotnet test GFramework.SourceGenerators.Tests/GFramework.SourceGenerators.Tests.csproj -c Release --filter "FullyQualifiedName~CqrsHandlerRegistryGeneratorTests.Emits_String_Fallback_Metadata_For_Mixed_Fallback_When_Runtime_Disallows_Multiple_Fallback_Attributes"`
+  - 结果：通过，`1/1` passed
+- `python3 scripts/license-header.py --check`
+  - 结果：通过
+  - 备注：当前 WSL worktree 需要显式绑定 `GIT_DIR` / `GIT_WORK_TREE` 后运行
+- `git diff --check`
+  - 结果：通过
 
 ## 下一推荐步骤
 
 1. 继续处理 `PR #307` 的剩余 review 收尾，优先保持 `ai-plan` active 入口与 trace 的单一锚点一致
-2. 若继续推进代码切片，优先复核 request / stream invoker provider runtime 合同以外是否还有同类对称测试缺口
+2. 若继续推进代码切片，优先复核 fallback metadata 与 generated invoker provider 之外是否还有同类 runtime contract gate 回归缺口
 3. 在进入下一批 runtime / generator 收敛前，保持最小 Release build 或 targeted test 作为权威验证
 
 ## 活跃文档
diff --git a/ai-plan/public/cqrs-rewrite/traces/cqrs-rewrite-migration-trace.md b/ai-plan/public/cqrs-rewrite/traces/cqrs-rewrite-migration-trace.md
index 7b5950db..c617dcae 100644
--- a/ai-plan/public/cqrs-rewrite/traces/cqrs-rewrite-migration-trace.md
+++ b/ai-plan/public/cqrs-rewrite/traces/cqrs-rewrite-migration-trace.md
@@ -62,3 +62,28 @@
 
 1. 继续使用 `origin/main` 作为 `$gframework-batch-boot 25` 的基线，复算 branch diff 后决定是否还能接下一批
 2. 若继续推进代码切片，优先查找 request / stream invoker provider runtime 合同之外的同类对称测试缺口
+
+### 阶段：mixed fallback attribute usage 回归（CQRS-REWRITE-RP-078）
+
+- 继续沿用 `$gframework-batch-boot 25`，当前 branch diff 仍低于阈值
+- 复核 fallback metadata runtime contract 后确认：
+  - mixed fallback 在 runtime 允许多个 fallback attribute 实例时已有直接 `Type` + 字符串拆分回归
+  - runtime 同时支持 `params Type[]` / `params string[]` 但不允许多个 fallback attribute 实例时，缺少锁定“整体回退到单个字符串 attribute”的回归
+- 已补齐：
+  - `Emits_String_Fallback_Metadata_For_Mixed_Fallback_When_Runtime_Disallows_Multiple_Fallback_Attributes`
+  - `ReplaceAttributeUsageForType` 测试辅助方法，用于构造 runtime attribute usage 变体而不复制大型 source fixture
+
+### 验证（RP-078）
+
+- `dotnet test GFramework.SourceGenerators.Tests/GFramework.SourceGenerators.Tests.csproj -c Release --filter "FullyQualifiedName~CqrsHandlerRegistryGeneratorTests.Emits_String_Fallback_Metadata_For_Mixed_Fallback_When_Runtime_Disallows_Multiple_Fallback_Attributes"`
+  - 结果：通过，`1/1` passed
+- `python3 scripts/license-header.py --check`
+  - 结果：通过
+  - 备注：当前 WSL worktree 需要显式绑定 `GIT_DIR` / `GIT_WORK_TREE` 后运行
+- `git diff --check`
+  - 结果：通过
+
+### 当前下一步（RP-078）
+
+1. 继续复算 branch diff vs `origin/main`，若仍低于 `25` 个文件可继续下一批
+2. 下一批优先查看 fallback metadata 与 generated invoker provider 之外是否还有同类 runtime contract gate 回归缺口