diff --git a/src/BuildFlow.Host/Endpoints/Workflow/WorkflowInstance/StartWorkflowInstanceEndpoint.cs b/src/BuildFlow.Host/Endpoints/Workflow/WorkflowInstance/StartWorkflowInstanceEndpoint.cs
index 208d7d0..efe60e1 100644
--- a/src/BuildFlow.Host/Endpoints/Workflow/WorkflowInstance/StartWorkflowInstanceEndpoint.cs
+++ b/src/BuildFlow.Host/Endpoints/Workflow/WorkflowInstance/StartWorkflowInstanceEndpoint.cs
@@ -1,18 +1,18 @@
 using MediatR;
 using Workflow.Application.Features.WorkflowInstances.Commands;
+using BuildFlow.Shared.Domain.Common;
+using BuildFlow.Host.Services.Users;
 
 namespace BuildFlow.Host.Endpoints.Workflow.WorkflowInstance;
 
 
 /// <summary>
-/// 发起流程实例端点。POST /instances，按定义创建实例并产生首个 token。
+/// 发起流程实例端点。POST /workflow-instances，按定义创建实例并产生首个 token。
 /// </summary>
-public class StartWorkflowInstanceEndpoint : Endpoint<StartWorkflowInstanceRequest, Guid>
+public class StartWorkflowInstanceEndpoint(
+    IMediator mediator,
+    ICurrentUserContext currentUserContext) : Endpoint<StartWorkflowInstanceRequest, Guid>
 {
-    private readonly IMediator _mediator;
-
-    public StartWorkflowInstanceEndpoint(IMediator mediator) => _mediator = mediator;
-
     public override void Configure()
     {
         Post("/workflow-instances");
@@ -25,8 +25,14 @@ public class StartWorkflowInstanceEndpoint : Endpoint<StartWorkflowInstanceReque
 
     public override async Task HandleAsync(StartWorkflowInstanceRequest req, CancellationToken ct)
     {
-        var command = new StartWorkflowInstanceCommand(req.DefinitionCode, req.Title, req.Variables, req.FormDataJson);
-        var result = await _mediator.Send(command, ct);
+        // 发起人取自当前认证用户，写入 WorkflowInstance.InitiatorId，供撤回鉴权与发起人通知使用。
+        var command = new StartWorkflowInstanceCommand(
+            req.DefinitionCode,
+            req.Title,
+            req.Variables,
+            req.FormDataJson,
+            currentUserContext.GetUserIdGuid());
+        var result = await mediator.Send(command, ct);
         await Send.OkAsync(result, ct);
     }
 }
diff --git a/src/modules/im/Application/Chat/Handlers/SendMessageCommandHandler.cs b/src/modules/im/Application/Chat/Handlers/SendMessageCommandHandler.cs
index 8fc0045..a2d8831 100644
--- a/src/modules/im/Application/Chat/Handlers/SendMessageCommandHandler.cs
+++ b/src/modules/im/Application/Chat/Handlers/SendMessageCommandHandler.cs
@@ -169,8 +169,9 @@ public class SendMessageCommandHandler(
 
         try
         {
-            // 异步调 RAG 问答（不阻塞消息发送响应）
-            var answer = await aiBotHandler.AnswerAsync(question, request.ConversationId, ct);
+            // 异步调 RAG 问答（不阻塞消息发送响应）。传 request.SenderId 作为发起人，
+            // 供 AI 触发工作流时写入 WorkflowInstance.InitiatorId。
+            var answer = await aiBotHandler.AnswerAsync(question, request.ConversationId, request.SenderId, ct);
 
             // AI 回复作为新消息发回会话（System 类型，标注来自 AI 助手）
             var aiMessage = new MessageDocument
diff --git a/src/modules/rag/Application/Integration/AiBotHandler.cs b/src/modules/rag/Application/Integration/AiBotHandler.cs
index 9f142ee..2b3211b 100644
--- a/src/modules/rag/Application/Integration/AiBotHandler.cs
+++ b/src/modules/rag/Application/Integration/AiBotHandler.cs
@@ -16,11 +16,11 @@ public class AiBotHandler(
     IMediator mediator,
     RagDbContext db) : IAiBotHandler
 {
-    public async Task<string> AnswerAsync(string question, Guid conversationId, CancellationToken ct)
+    public async Task<string> AnswerAsync(string question, Guid conversationId, Guid initiatorId, CancellationToken ct)
     {
         // 串联链路4：AI 对话 → 触发工作流
         // 检测"发起/启动/申请 XXX 流程"等意图
-        var triggerResult = await TryDetectWorkflowIntentAsync(question, ct);
+        var triggerResult = await TryDetectWorkflowIntentAsync(question, initiatorId, ct);
         if (triggerResult is not null)
             return triggerResult;
 
@@ -49,7 +49,7 @@ public class AiBotHandler(
     /// 检测工作流触发意图（如"帮我发起报销流程"）。
     /// 命中则触发对应流程并返回结果消息，未命中返回 null 走默认 RAG 问答。
     /// </summary>
-    private async Task<string?> TryDetectWorkflowIntentAsync(string question, CancellationToken ct)
+    private async Task<string?> TryDetectWorkflowIntentAsync(string question, Guid initiatorId, CancellationToken ct)
     {
         var lowerQ = question.ToLowerInvariant();
 
@@ -69,7 +69,7 @@ public class AiBotHandler(
 
         if (string.IsNullOrWhiteSpace(flowName)) return null;
 
-        var result = await mediator.Send(new StartWorkflowByNameCommand(flowName, Guid.Empty, null), ct);
+        var result = await mediator.Send(new StartWorkflowByNameCommand(flowName, initiatorId, null), ct);
 
         if (result.Success)
         {
diff --git a/src/modules/workflow/Application/Features/WorkflowInstances/Commands/StartWorkflowInstanceCommand.cs b/src/modules/workflow/Application/Features/WorkflowInstances/Commands/StartWorkflowInstanceCommand.cs
index 26b7226..d7c1f52 100644
--- a/src/modules/workflow/Application/Features/WorkflowInstances/Commands/StartWorkflowInstanceCommand.cs
+++ b/src/modules/workflow/Application/Features/WorkflowInstances/Commands/StartWorkflowInstanceCommand.cs
@@ -6,11 +6,13 @@ namespace Workflow.Application.Features.WorkflowInstances.Commands;
 /// <summary>
 /// 发起WorkflowInstance命令。封装写操作的入参与意图。
 /// </summary>
+/// <param name="InitiatorId">发起人用户 ID。写入 WorkflowInstance.InitiatorId，供撤回鉴权与发起人通知使用。</param>
 public record StartWorkflowInstanceCommand(
     string DefinitionCode,
     string Title,
     string? Variables,
-    string? FormDataJson
+    string? FormDataJson,
+    Guid InitiatorId
 ) : IRequest<Guid>;
 
 /// <summary>
diff --git a/src/modules/workflow/Application/Features/WorkflowInstances/Handlers/StartWorkflowInstanceCommandHandler.cs b/src/modules/workflow/Application/Features/WorkflowInstances/Handlers/StartWorkflowInstanceCommandHandler.cs
index 3a67527..c694caa 100644
--- a/src/modules/workflow/Application/Features/WorkflowInstances/Handlers/StartWorkflowInstanceCommandHandler.cs
+++ b/src/modules/workflow/Application/Features/WorkflowInstances/Handlers/StartWorkflowInstanceCommandHandler.cs
@@ -83,7 +83,7 @@ public class StartWorkflowInstanceCommandHandler(
             Title = request.Title,
             Status = InstanceStatus.Running,
             Variables = BuildVariablesJson(normalizedFormDataJson, request.Variables),
-            InitiatorId = Guid.Empty
+            InitiatorId = request.InitiatorId
         };
 
         db.WorkflowInstances.Add(instance);
diff --git a/src/modules/workflow/Application/Integration/Handlers/StartWorkflowByNameCommandHandler.cs b/src/modules/workflow/Application/Integration/Handlers/StartWorkflowByNameCommandHandler.cs
index 6ea9e55..0c43b72 100644
--- a/src/modules/workflow/Application/Integration/Handlers/StartWorkflowByNameCommandHandler.cs
+++ b/src/modules/workflow/Application/Integration/Handlers/StartWorkflowByNameCommandHandler.cs
@@ -40,7 +40,8 @@ public sealed class StartWorkflowByNameCommandHandler(
                     definition.Code ?? definition.Id.ToString(),
                     $"{request.DefinitionKey}-{DateTime.UtcNow:MMddHHmm}",
                     request.Variables,
-                    null),
+                    null,
+                    request.InitiatorId),
                 ct);
 
             return new WorkflowTriggerResultDto(true, instanceId, request.DefinitionKey, null);
diff --git a/src/shared/BuildFlow.Shared/Integration/IAiBotHandler.cs b/src/shared/BuildFlow.Shared/Integration/IAiBotHandler.cs
index 9c9cfb2..59f20f4 100644
--- a/src/shared/BuildFlow.Shared/Integration/IAiBotHandler.cs
+++ b/src/shared/BuildFlow.Shared/Integration/IAiBotHandler.cs
@@ -22,7 +22,8 @@ public interface IAiBotHandler
     /// </summary>
     /// <param name="question">用户提问内容（去掉 @AI 前缀后的纯问题）</param>
     /// <param name="conversationId">IM 会话 ID（可用于关联知识库）</param>
+    /// <param name="initiatorId">提问发起人用户 ID（触发工作流时作为实例发起人）</param>
     /// <param name="ct">取消令牌</param>
     /// <returns>AI 回答文本</returns>
-    Task<string> AnswerAsync(string question, Guid conversationId, CancellationToken ct);
+    Task<string> AnswerAsync(string question, Guid conversationId, Guid initiatorId, CancellationToken ct);
 }
diff --git a/tests/BuildFlow.Workflow.Tests/Handlers/WorkflowInstanceHandlerTests.cs b/tests/BuildFlow.Workflow.Tests/Handlers/WorkflowInstanceHandlerTests.cs
index 3094be1..703662c 100644
--- a/tests/BuildFlow.Workflow.Tests/Handlers/WorkflowInstanceHandlerTests.cs
+++ b/tests/BuildFlow.Workflow.Tests/Handlers/WorkflowInstanceHandlerTests.cs
@@ -17,6 +17,8 @@ namespace BuildFlow.Workflow.Tests.Handlers;
 
 public class WorkflowInstanceHandlerTests
 {
+    private static readonly Guid TestInitiatorId = Guid.Parse("11111111-1111-1111-1111-111111111111");
+
     private const string ComputedExpenseSchema = """
     {
       "type": "object",
@@ -123,8 +125,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "running-test",
             Title: "Test Instance",
             Variables: null,
-            FormDataJson: null
-        );
+            FormDataJson: null,
+            InitiatorId: TestInitiatorId);
 
         // Act
         var instanceId = await handler.Handle(command, CancellationToken.None);
@@ -136,6 +138,8 @@ public class WorkflowInstanceHandlerTests
         instance.Should().NotBeNull();
         instance!.Status.Should().Be(InstanceStatus.Running);
         instance.Title.Should().Be("Test Instance");
+        // 发起人必须正确写入，供撤回鉴权与发起人通知使用（修复历史 Guid.Empty 缺陷）
+        instance.InitiatorId.Should().Be(TestInitiatorId);
     }
 
     [Fact]
@@ -149,8 +153,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "token-test",
             Title: "Token Test",
             Variables: null,
-            FormDataJson: null
-        );
+            FormDataJson: null,
+            InitiatorId: TestInitiatorId);
 
         // Act
         var instanceId = await handler.Handle(command, CancellationToken.None);
@@ -175,8 +179,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "nonexistent-code",
             Title: "Should Fail",
             Variables: null,
-            FormDataJson: null
-        );
+            FormDataJson: null,
+            InitiatorId: TestInitiatorId);
 
         // Act
         var act = () => handler.Handle(command, CancellationToken.None);
@@ -208,8 +212,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "disabled-wf",
             Title: "Should Fail",
             Variables: null,
-            FormDataJson: null
-        );
+            FormDataJson: null,
+            InitiatorId: TestInitiatorId);
 
         // Act
         var act = () => handler.Handle(command, CancellationToken.None);
@@ -243,8 +247,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "form-vars-test",
             Title: "Expense",
             Variables: null,
-            FormDataJson: """{"amount":6500,"category":"travel"}"""
-        );
+            FormDataJson: """{"amount":6500,"category":"travel"}""",
+            InitiatorId: TestInitiatorId);
 
         // Act
         var instanceId = await handler.Handle(command, CancellationToken.None);
@@ -286,7 +290,8 @@ public class WorkflowInstanceHandlerTests
                 DefinitionCode: "computed-start-form-test",
                 Title: "Computed Start",
                 Variables: null,
-                FormDataJson: """{"quantity":2,"unitPrice":15,"total":1}"""),
+                FormDataJson: """{"quantity":2,"unitPrice":15,"total":1}""",
+                InitiatorId: TestInitiatorId),
             CancellationToken.None);
 
         var savedData = await db.FormData.SingleAsync(f => f.InstanceId == instanceId);
@@ -326,8 +331,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "deleted-start-form-test",
             Title: "X",
             Variables: null,
-            FormDataJson: """{"amount":100}"""
-        );
+            FormDataJson: """{"amount":100}""",
+            InitiatorId: TestInitiatorId);
 
         // Act
         var act = () => handler.Handle(command, CancellationToken.None);
@@ -360,8 +365,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "nonexistent-start-form-test",
             Title: "X",
             Variables: null,
-            FormDataJson: """{"amount":100}"""
-        );
+            FormDataJson: """{"amount":100}""",
+            InitiatorId: TestInitiatorId);
 
         var act = () => handler.Handle(command, CancellationToken.None);
 
@@ -396,8 +401,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "disabled-start-form-test",
             Title: "X",
             Variables: null,
-            FormDataJson: """{"amount":100}"""
-        );
+            FormDataJson: """{"amount":100}""",
+            InitiatorId: TestInitiatorId);
 
         var act = () => handler.Handle(command, CancellationToken.None);
 
@@ -433,8 +438,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "merge-vars-test",
             Title: "Leave",
             Variables: """{"days":5,"urgent":true}""",
-            FormDataJson: """{"days":2,"leaveType":"annual"}"""
-        );
+            FormDataJson: """{"days":2,"leaveType":"annual"}""",
+            InitiatorId: TestInitiatorId);
 
         // Act
         var instanceId = await handler.Handle(command, CancellationToken.None);
@@ -484,8 +489,8 @@ public class WorkflowInstanceHandlerTests
             DefinitionCode: "invalid-start-form-test",
             Title: "Invalid Start Form",
             Variables: null,
-            FormDataJson: """{"name":""}"""
-        );
+            FormDataJson: """{"name":""}""",
+            InitiatorId: TestInitiatorId);
 
         // Act
         var act = () => handler.Handle(command, CancellationToken.None);
@@ -559,7 +564,8 @@ public class WorkflowInstanceHandlerTests
                 "nested-start-form-test",
                 "嵌套合法发起",
                 null,
-                """{"leaveType":"annual","dateRange":{"startDate":"2026-06-15","endDate":"2026-06-16"}}"""),
+                """{"leaveType":"annual","dateRange":{"startDate":"2026-06-15","endDate":"2026-06-16"}}""",
+                TestInitiatorId),
             CancellationToken.None);
 
         instanceId.Should().NotBeEmpty();
@@ -571,7 +577,8 @@ public class WorkflowInstanceHandlerTests
                 "nested-start-form-test",
                 "嵌套缺失",
                 null,
-                """{"leaveType":"annual","dateRange":{}}"""),
+                """{"leaveType":"annual","dateRange":{}}""",
+                TestInitiatorId),
             CancellationToken.None);
 
         await act.Should().ThrowAsync<BusinessException>()