diff --git a/src/modules/Elsa.AzureServiceBus/Activities/MessageReceived.cs b/src/modules/Elsa.AzureServiceBus/Activities/MessageReceived.cs
index 11c1f06c8..7ba264433 100644
--- a/src/modules/Elsa.AzureServiceBus/Activities/MessageReceived.cs
+++ b/src/modules/Elsa.AzureServiceBus/Activities/MessageReceived.cs
@@ -3,6 +3,7 @@ using Elsa.AzureServiceBus.Models;
 using Elsa.Common.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.AzureServiceBus/Activities/SendMessage.cs b/src/modules/Elsa.AzureServiceBus/Activities/SendMessage.cs
index ce3b832e8..44510f3ed 100644
--- a/src/modules/Elsa.AzureServiceBus/Activities/SendMessage.cs
+++ b/src/modules/Elsa.AzureServiceBus/Activities/SendMessage.cs
@@ -2,6 +2,7 @@ using Azure.Messaging.ServiceBus;
 using Elsa.Common.Contracts;
 using Elsa.Common.Services;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
diff --git a/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowDefinitionStore.cs b/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowDefinitionStore.cs
index 8e8a5689f..176e0483a 100644
--- a/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowDefinitionStore.cs
+++ b/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowDefinitionStore.cs
@@ -8,6 +8,7 @@ using Elsa.Dapper.Modules.Management.Records;
 using Elsa.Dapper.Services;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Contracts;
 using Elsa.Workflows.Management.Entities;
diff --git a/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowInstanceStore.cs b/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowInstanceStore.cs
index b07143e63..aa2505922 100644
--- a/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowInstanceStore.cs
+++ b/src/modules/Elsa.Dapper/Modules/Management/Services/DapperWorkflowInstanceStore.cs
@@ -6,6 +6,7 @@ using Elsa.Dapper.Models;
 using Elsa.Dapper.Modules.Management.Records;
 using Elsa.Dapper.Services;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Contracts;
diff --git a/src/modules/Elsa.Dapper/Modules/Runtime/Services/DapperWorkflowStateStore.cs b/src/modules/Elsa.Dapper/Modules/Runtime/Services/DapperWorkflowStateStore.cs
index dd8618e2b..e1beb280a 100644
--- a/src/modules/Elsa.Dapper/Modules/Runtime/Services/DapperWorkflowStateStore.cs
+++ b/src/modules/Elsa.Dapper/Modules/Runtime/Services/DapperWorkflowStateStore.cs
@@ -2,6 +2,7 @@ using Elsa.Dapper.Contracts;
 using Elsa.Dapper.Extensions;
 using Elsa.Dapper.Modules.Runtime.Records;
 using Elsa.Dapper.Services;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/modules/Elsa.Dsl/Extensions/TypeSystemExtensions.cs b/src/modules/Elsa.Dsl/Extensions/TypeSystemExtensions.cs
index 0ed397f27..30f071218 100644
--- a/src/modules/Elsa.Dsl/Extensions/TypeSystemExtensions.cs
+++ b/src/modules/Elsa.Dsl/Extensions/TypeSystemExtensions.cs
@@ -1,4 +1,5 @@
 using Elsa.Dsl.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitWorkflowVariable.cs b/src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitWorkflowVariable.cs
index 882dbc570..759c35988 100644
--- a/src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitWorkflowVariable.cs
+++ b/src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitWorkflowVariable.cs
@@ -1,4 +1,5 @@
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Dsl.Interpreters;
diff --git a/src/modules/Elsa.EntityFrameworkCore/Modules/Management/Configurations.cs b/src/modules/Elsa.EntityFrameworkCore/Modules/Management/Configurations.cs
index a9fdc122d..9a4a83200 100644
--- a/src/modules/Elsa.EntityFrameworkCore/Modules/Management/Configurations.cs
+++ b/src/modules/Elsa.EntityFrameworkCore/Modules/Management/Configurations.cs
@@ -1,4 +1,5 @@
 using System.Linq.Expressions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Entities;
 using Microsoft.EntityFrameworkCore;
diff --git a/src/modules/Elsa.EntityFrameworkCore/Modules/Management/WorkflowDefinitionStore.cs b/src/modules/Elsa.EntityFrameworkCore/Modules/Management/WorkflowDefinitionStore.cs
index d3e4e8705..3fee1a377 100644
--- a/src/modules/Elsa.EntityFrameworkCore/Modules/Management/WorkflowDefinitionStore.cs
+++ b/src/modules/Elsa.EntityFrameworkCore/Modules/Management/WorkflowDefinitionStore.cs
@@ -2,6 +2,7 @@ using Elsa.Common.Models;
 using Elsa.EntityFrameworkCore.Common;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Contracts;
 using Elsa.Workflows.Management.Entities;
diff --git a/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/Configurations.cs b/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/Configurations.cs
index dd3dad254..99ef4b28a 100644
--- a/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/Configurations.cs
+++ b/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/Configurations.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
 using Elsa.Workflows.Runtime.Entities;
diff --git a/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/WorkflowStateStore.cs b/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/WorkflowStateStore.cs
index 5f4918e00..60ccf40df 100644
--- a/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/WorkflowStateStore.cs
+++ b/src/modules/Elsa.EntityFrameworkCore/Modules/Runtime/WorkflowStateStore.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Contracts;
 using Elsa.EntityFrameworkCore.Common;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/modules/Elsa.Http/Extensions/ActivityContextExtensions.cs b/src/modules/Elsa.Http/Extensions/ActivityContextExtensions.cs
index 05696eade..338963e68 100644
--- a/src/modules/Elsa.Http/Extensions/ActivityContextExtensions.cs
+++ b/src/modules/Elsa.Http/Extensions/ActivityContextExtensions.cs
@@ -1,4 +1,5 @@
 using Elsa.Http.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Http/Extensions/OutputExtensions.cs b/src/modules/Elsa.Http/Extensions/OutputExtensions.cs
index febedb205..45e007b5a 100644
--- a/src/modules/Elsa.Http/Extensions/OutputExtensions.cs
+++ b/src/modules/Elsa.Http/Extensions/OutputExtensions.cs
@@ -1,3 +1,5 @@
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Http/Middleware/WorkflowsMiddleware.cs b/src/modules/Elsa.Http/Middleware/WorkflowsMiddleware.cs
index d87537323..3ecfffdd6 100644
--- a/src/modules/Elsa.Http/Middleware/WorkflowsMiddleware.cs
+++ b/src/modules/Elsa.Http/Middleware/WorkflowsMiddleware.cs
@@ -12,6 +12,7 @@ using System.Net;
 using System.Net.Mime;
 using System.Text.Json;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.State;
 
 namespace Elsa.Http.Middleware;
diff --git a/src/modules/Elsa.JavaScript/Extensions/WorkflowExecutionContextExtensions.cs b/src/modules/Elsa.JavaScript/Extensions/WorkflowExecutionContextExtensions.cs
index 36df3e6cb..437ffaa2b 100644
--- a/src/modules/Elsa.JavaScript/Extensions/WorkflowExecutionContextExtensions.cs
+++ b/src/modules/Elsa.JavaScript/Extensions/WorkflowExecutionContextExtensions.cs
@@ -1,4 +1,5 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.JavaScript/Handlers/WorkflowDefinitionActivityJavaScriptHandler.cs b/src/modules/Elsa.JavaScript/Handlers/WorkflowDefinitionActivityJavaScriptHandler.cs
index f759536f6..87b0bb511 100644
--- a/src/modules/Elsa.JavaScript/Handlers/WorkflowDefinitionActivityJavaScriptHandler.cs
+++ b/src/modules/Elsa.JavaScript/Handlers/WorkflowDefinitionActivityJavaScriptHandler.cs
@@ -4,6 +4,7 @@ using Elsa.Extensions;
 using Elsa.JavaScript.Notifications;
 using Elsa.Mediator.Contracts;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Humanizer;
 using JetBrains.Annotations;
diff --git a/src/modules/Elsa.JavaScript/Services/JintJavaScriptEvaluator.cs b/src/modules/Elsa.JavaScript/Services/JintJavaScriptEvaluator.cs
index 1159e643a..6a1eb387e 100644
--- a/src/modules/Elsa.JavaScript/Services/JintJavaScriptEvaluator.cs
+++ b/src/modules/Elsa.JavaScript/Services/JintJavaScriptEvaluator.cs
@@ -8,6 +8,7 @@ using Elsa.JavaScript.Extensions;
 using Elsa.JavaScript.Notifications;
 using Elsa.JavaScript.Options;
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Humanizer;
 using Jint;
diff --git a/src/modules/Elsa.Liquid/Handlers/ConfigureLiquidEngine.cs b/src/modules/Elsa.Liquid/Handlers/ConfigureLiquidEngine.cs
index 005ff31b6..4a0e2669e 100644
--- a/src/modules/Elsa.Liquid/Handlers/ConfigureLiquidEngine.cs
+++ b/src/modules/Elsa.Liquid/Handlers/ConfigureLiquidEngine.cs
@@ -5,6 +5,7 @@ using Elsa.Liquid.Helpers;
 using Elsa.Liquid.Notifications;
 using Elsa.Liquid.Options;
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Options;
 using Fluid;
diff --git a/src/modules/Elsa.Liquid/Helpers/LiquidActivityModel.cs b/src/modules/Elsa.Liquid/Helpers/LiquidActivityModel.cs
index fe177c5bc..5180ffdaf 100644
--- a/src/modules/Elsa.Liquid/Helpers/LiquidActivityModel.cs
+++ b/src/modules/Elsa.Liquid/Helpers/LiquidActivityModel.cs
@@ -1,4 +1,5 @@
-using Elsa.Workflows.Core.Models;
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Liquid.Helpers;
 
diff --git a/src/modules/Elsa.MassTransit/Activities/MessageReceived.cs b/src/modules/Elsa.MassTransit/Activities/MessageReceived.cs
index 6582e64cb..c8de283d8 100644
--- a/src/modules/Elsa.MassTransit/Activities/MessageReceived.cs
+++ b/src/modules/Elsa.MassTransit/Activities/MessageReceived.cs
@@ -3,6 +3,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.MassTransit.Implementations;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.MassTransit.Activities;
diff --git a/src/modules/Elsa.MassTransit/Activities/PublishMessage.cs b/src/modules/Elsa.MassTransit/Activities/PublishMessage.cs
index 7a0d44582..6bae459ac 100644
--- a/src/modules/Elsa.MassTransit/Activities/PublishMessage.cs
+++ b/src/modules/Elsa.MassTransit/Activities/PublishMessage.cs
@@ -3,6 +3,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Helpers;
 using Elsa.Extensions;
 using Elsa.MassTransit.Implementations;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 using MassTransit;
diff --git a/src/modules/Elsa.MongoDb/Features/MongoDbFeature.cs b/src/modules/Elsa.MongoDb/Features/MongoDbFeature.cs
index 8554eea66..6d035fc79 100644
--- a/src/modules/Elsa.MongoDb/Features/MongoDbFeature.cs
+++ b/src/modules/Elsa.MongoDb/Features/MongoDbFeature.cs
@@ -2,6 +2,7 @@ using Elsa.Features.Abstractions;
 using Elsa.Features.Services;
 using Elsa.MongoDB.Options;
 using Elsa.MongoDb.Serializers;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
diff --git a/src/modules/Elsa.MongoDb/Modules/Runtime/WorkflowStateStore.cs b/src/modules/Elsa.MongoDb/Modules/Runtime/WorkflowStateStore.cs
index 13491fa9f..2e53ed81d 100644
--- a/src/modules/Elsa.MongoDb/Modules/Runtime/WorkflowStateStore.cs
+++ b/src/modules/Elsa.MongoDb/Modules/Runtime/WorkflowStateStore.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Contracts;
 using Elsa.MongoDb.Common;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/modules/Elsa.MongoDb/Serializers/VariableSerializer.cs b/src/modules/Elsa.MongoDb/Serializers/VariableSerializer.cs
index a55fdbd75..ef36e8de8 100644
--- a/src/modules/Elsa.MongoDb/Serializers/VariableSerializer.cs
+++ b/src/modules/Elsa.MongoDb/Serializers/VariableSerializer.cs
@@ -1,4 +1,5 @@
 using Elsa.Expressions.Services;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 using Microsoft.Extensions.Logging.Abstractions;
diff --git a/src/modules/Elsa.ProtoActor/Grains/WorkflowGrain.cs b/src/modules/Elsa.ProtoActor/Grains/WorkflowGrain.cs
index d3ab9232d..b0987c058 100644
--- a/src/modules/Elsa.ProtoActor/Grains/WorkflowGrain.cs
+++ b/src/modules/Elsa.ProtoActor/Grains/WorkflowGrain.cs
@@ -10,7 +10,7 @@ using Proto;
 using Proto.Cluster;
 using Proto.Persistence;
 using Exception = System.Exception;
-using WorkflowStatus = Elsa.Workflows.Core.Models.WorkflowStatus;
+using WorkflowStatus = Elsa.Workflows.Core.WorkflowStatus;
 using ProtoBookmark = Elsa.ProtoActor.Protos.Bookmark;
 
 namespace Elsa.ProtoActor.Grains;
diff --git a/src/modules/Elsa.ProtoActor/Handlers/UpdateRunningWorkflowsHandler.cs b/src/modules/Elsa.ProtoActor/Handlers/UpdateRunningWorkflowsHandler.cs
index 92519846a..d1be9dc7d 100644
--- a/src/modules/Elsa.ProtoActor/Handlers/UpdateRunningWorkflowsHandler.cs
+++ b/src/modules/Elsa.ProtoActor/Handlers/UpdateRunningWorkflowsHandler.cs
@@ -5,7 +5,7 @@ using Elsa.ProtoActor.Grains;
 using Elsa.ProtoActor.Protos;
 using Elsa.Workflows.Core.Notifications;
 using Proto.Cluster;
-using WorkflowStatus = Elsa.Workflows.Core.Models.WorkflowStatus;
+using WorkflowStatus = Elsa.Workflows.Core.WorkflowStatus;
 
 namespace Elsa.ProtoActor.Handlers;
 
diff --git a/src/modules/Elsa.ProtoActor/Mappers/WorkflowStatusMapper.cs b/src/modules/Elsa.ProtoActor/Mappers/WorkflowStatusMapper.cs
index 703a4bb82..7fdfcc266 100644
--- a/src/modules/Elsa.ProtoActor/Mappers/WorkflowStatusMapper.cs
+++ b/src/modules/Elsa.ProtoActor/Mappers/WorkflowStatusMapper.cs
@@ -1,4 +1,4 @@
-using Elsa.Workflows.Core.Models;
+using Elsa.Workflows.Core;
 using ProtoWorkflowStatus = Elsa.ProtoActor.Protos.WorkflowStatus;
 
 namespace Elsa.ProtoActor.Mappers;
diff --git a/src/modules/Elsa.ProtoActor/Mappers/WorkflowSubStatusMapper.cs b/src/modules/Elsa.ProtoActor/Mappers/WorkflowSubStatusMapper.cs
index 4728e78e7..5f61c07d3 100644
--- a/src/modules/Elsa.ProtoActor/Mappers/WorkflowSubStatusMapper.cs
+++ b/src/modules/Elsa.ProtoActor/Mappers/WorkflowSubStatusMapper.cs
@@ -1,4 +1,4 @@
-using Elsa.Workflows.Core.Models;
+using Elsa.Workflows.Core;
 using ProtoWorkflowSubStatus = Elsa.ProtoActor.Protos.WorkflowSubStatus;
 
 namespace Elsa.ProtoActor.Mappers;
diff --git a/src/modules/Elsa.Scheduling/Activities/Cron.cs b/src/modules/Elsa.Scheduling/Activities/Cron.cs
index 0b691775b..ba4773286 100644
--- a/src/modules/Elsa.Scheduling/Activities/Cron.cs
+++ b/src/modules/Elsa.Scheduling/Activities/Cron.cs
@@ -2,6 +2,7 @@
 using System.Text.Json.Serialization;
 using Elsa.Extensions;
 using Elsa.Scheduling.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.Scheduling/Activities/Delay.cs b/src/modules/Elsa.Scheduling/Activities/Delay.cs
index 8ccebe3eb..8de3ab2a3 100644
--- a/src/modules/Elsa.Scheduling/Activities/Delay.cs
+++ b/src/modules/Elsa.Scheduling/Activities/Delay.cs
@@ -3,7 +3,9 @@ using System.Text.Json.Serialization;
 using Elsa.Common.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Scheduling.Activities;
diff --git a/src/modules/Elsa.Scheduling/Activities/StartAt.cs b/src/modules/Elsa.Scheduling/Activities/StartAt.cs
index 27225962c..e90fb78a0 100644
--- a/src/modules/Elsa.Scheduling/Activities/StartAt.cs
+++ b/src/modules/Elsa.Scheduling/Activities/StartAt.cs
@@ -3,7 +3,9 @@ using System.Text.Json.Serialization;
 using Elsa.Common.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.Logging;
 
diff --git a/src/modules/Elsa.Scheduling/Activities/Timer.cs b/src/modules/Elsa.Scheduling/Activities/Timer.cs
index 429e9a4ff..85ad05d6b 100644
--- a/src/modules/Elsa.Scheduling/Activities/Timer.cs
+++ b/src/modules/Elsa.Scheduling/Activities/Timer.cs
@@ -2,6 +2,7 @@
 using System.Text.Json.Serialization;
 using Elsa.Common.Contracts;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.Telnyx/Activities/AnswerCall.cs b/src/modules/Elsa.Telnyx/Activities/AnswerCall.cs
index dadf604d5..8416989f8 100644
--- a/src/modules/Elsa.Telnyx/Activities/AnswerCall.cs
+++ b/src/modules/Elsa.Telnyx/Activities/AnswerCall.cs
@@ -7,6 +7,7 @@ using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
 using Elsa.Telnyx.Payloads.Call;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Activities.Flowchart.Models;
 using Elsa.Workflows.Core.Attributes;
diff --git a/src/modules/Elsa.Telnyx/Activities/BridgeCalls.cs b/src/modules/Elsa.Telnyx/Activities/BridgeCalls.cs
index 18c353a35..33cf48475 100644
--- a/src/modules/Elsa.Telnyx/Activities/BridgeCalls.cs
+++ b/src/modules/Elsa.Telnyx/Activities/BridgeCalls.cs
@@ -6,6 +6,7 @@ using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
 using Elsa.Telnyx.Payloads.Call;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Telnyx/Activities/GatherUsingAudio.cs b/src/modules/Elsa.Telnyx/Activities/GatherUsingAudio.cs
index 270b29b7f..abf4649b3 100644
--- a/src/modules/Elsa.Telnyx/Activities/GatherUsingAudio.cs
+++ b/src/modules/Elsa.Telnyx/Activities/GatherUsingAudio.cs
@@ -7,6 +7,7 @@ using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
 using Elsa.Telnyx.Payloads.Call;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Telnyx/Activities/GetCallStatus.cs b/src/modules/Elsa.Telnyx/Activities/GetCallStatus.cs
index d6780f391..7f783bfe7 100644
--- a/src/modules/Elsa.Telnyx/Activities/GetCallStatus.cs
+++ b/src/modules/Elsa.Telnyx/Activities/GetCallStatus.cs
@@ -2,6 +2,7 @@
 using System.Text.Json.Serialization;
 using Elsa.Extensions;
 using Elsa.Telnyx.Client.Services;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Telnyx/Activities/HangupCall.cs b/src/modules/Elsa.Telnyx/Activities/HangupCall.cs
index 08fb7c373..40d1a0d39 100644
--- a/src/modules/Elsa.Telnyx/Activities/HangupCall.cs
+++ b/src/modules/Elsa.Telnyx/Activities/HangupCall.cs
@@ -4,6 +4,7 @@ using Elsa.Extensions;
 using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Telnyx/Activities/StopAudioPlayback.cs b/src/modules/Elsa.Telnyx/Activities/StopAudioPlayback.cs
index a02f00224..25d6eebbf 100644
--- a/src/modules/Elsa.Telnyx/Activities/StopAudioPlayback.cs
+++ b/src/modules/Elsa.Telnyx/Activities/StopAudioPlayback.cs
@@ -4,6 +4,7 @@ using Elsa.Extensions;
 using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Telnyx/Activities/StopRecording.cs b/src/modules/Elsa.Telnyx/Activities/StopRecording.cs
index 1a649915e..054c75baa 100644
--- a/src/modules/Elsa.Telnyx/Activities/StopRecording.cs
+++ b/src/modules/Elsa.Telnyx/Activities/StopRecording.cs
@@ -4,6 +4,7 @@ using Elsa.Extensions;
 using Elsa.Telnyx.Client.Models;
 using Elsa.Telnyx.Client.Services;
 using Elsa.Telnyx.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Telnyx/Activities/WebhookEvent.cs b/src/modules/Elsa.Telnyx/Activities/WebhookEvent.cs
index 63c69e039..655f80a3d 100644
--- a/src/modules/Elsa.Telnyx/Activities/WebhookEvent.cs
+++ b/src/modules/Elsa.Telnyx/Activities/WebhookEvent.cs
@@ -6,7 +6,9 @@ using Elsa.Telnyx.Bookmarks;
 using Elsa.Telnyx.Helpers;
 using Elsa.Telnyx.Models;
 using Elsa.Telnyx.Payloads.Abstract;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Telnyx.Activities;
diff --git a/src/modules/Elsa.Telnyx/Extensions/ActivityExecutionExtensions.cs b/src/modules/Elsa.Telnyx/Extensions/ActivityExecutionExtensions.cs
index ce924c7e3..79c32e3da 100644
--- a/src/modules/Elsa.Telnyx/Extensions/ActivityExecutionExtensions.cs
+++ b/src/modules/Elsa.Telnyx/Extensions/ActivityExecutionExtensions.cs
@@ -1,5 +1,6 @@
 using Elsa.Extensions;
 using Elsa.Telnyx.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Telnyx.Extensions;
diff --git a/src/modules/Elsa.Telnyx/Providers/WebhookEventActivityProvider.cs b/src/modules/Elsa.Telnyx/Providers/WebhookEventActivityProvider.cs
index 57b6feeb7..a974c19d0 100644
--- a/src/modules/Elsa.Telnyx/Providers/WebhookEventActivityProvider.cs
+++ b/src/modules/Elsa.Telnyx/Providers/WebhookEventActivityProvider.cs
@@ -5,6 +5,7 @@ using Elsa.Telnyx.Activities;
 using Elsa.Telnyx.Attributes;
 using Elsa.Telnyx.Helpers;
 using Elsa.Telnyx.Payloads.Abstract;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Extensions;
diff --git a/src/modules/Elsa.WorkflowContexts/Abstractions/WorkflowContextProvider.cs b/src/modules/Elsa.WorkflowContexts/Abstractions/WorkflowContextProvider.cs
index ef46079e4..2e57c566d 100644
--- a/src/modules/Elsa.WorkflowContexts/Abstractions/WorkflowContextProvider.cs
+++ b/src/modules/Elsa.WorkflowContexts/Abstractions/WorkflowContextProvider.cs
@@ -1,4 +1,5 @@
 using Elsa.WorkflowContexts.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
diff --git a/src/modules/Elsa.WorkflowContexts/Activities/SetWorkflowContextParameter.cs b/src/modules/Elsa.WorkflowContexts/Activities/SetWorkflowContextParameter.cs
index 1d0c654e9..890ce2564 100644
--- a/src/modules/Elsa.WorkflowContexts/Activities/SetWorkflowContextParameter.cs
+++ b/src/modules/Elsa.WorkflowContexts/Activities/SetWorkflowContextParameter.cs
@@ -3,6 +3,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.WorkflowContexts.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
diff --git a/src/modules/Elsa.WorkflowContexts/Contracts/IWorkflowContextProvider.cs b/src/modules/Elsa.WorkflowContexts/Contracts/IWorkflowContextProvider.cs
index fdf70fa22..d239b147b 100644
--- a/src/modules/Elsa.WorkflowContexts/Contracts/IWorkflowContextProvider.cs
+++ b/src/modules/Elsa.WorkflowContexts/Contracts/IWorkflowContextProvider.cs
@@ -1,4 +1,5 @@
-using Elsa.Workflows.Core.Models;
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Models;
 
 namespace Elsa.WorkflowContexts.Contracts;
 
diff --git a/src/modules/Elsa.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs b/src/modules/Elsa.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
index eef1a8074..d343dcea7 100644
--- a/src/modules/Elsa.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
+++ b/src/modules/Elsa.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
@@ -1,5 +1,6 @@
 using Elsa.Expressions.Models;
 using Elsa.WorkflowContexts.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
diff --git a/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextActivityExecutionMiddleware.cs b/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextActivityExecutionMiddleware.cs
index 28fd3e29c..975828efc 100644
--- a/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextActivityExecutionMiddleware.cs
+++ b/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextActivityExecutionMiddleware.cs
@@ -1,5 +1,6 @@
 using Elsa.Extensions;
 using Elsa.WorkflowContexts.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.ActivityExecution;
diff --git a/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextWorkflowExecutionMiddleware.cs b/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextWorkflowExecutionMiddleware.cs
index 5939d9bcf..6d329045f 100644
--- a/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextWorkflowExecutionMiddleware.cs
+++ b/src/modules/Elsa.WorkflowContexts/Middleware/WorkflowContextWorkflowExecutionMiddleware.cs
@@ -1,5 +1,6 @@
 using Elsa.Extensions;
 using Elsa.WorkflowContexts.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.WorkflowExecution;
 using Microsoft.Extensions.DependencyInjection;
diff --git a/src/modules/Elsa.WorkflowContexts/Scripting/JavaScript/ConfigureJavaScriptEngine.cs b/src/modules/Elsa.WorkflowContexts/Scripting/JavaScript/ConfigureJavaScriptEngine.cs
index 72b522f25..eb74d45aa 100644
--- a/src/modules/Elsa.WorkflowContexts/Scripting/JavaScript/ConfigureJavaScriptEngine.cs
+++ b/src/modules/Elsa.WorkflowContexts/Scripting/JavaScript/ConfigureJavaScriptEngine.cs
@@ -6,6 +6,7 @@ using Elsa.JavaScript.TypeDefinitions.Builders;
 using Elsa.JavaScript.TypeDefinitions.Contracts;
 using Elsa.JavaScript.TypeDefinitions.Models;
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.WorkflowContexts.Scripting.JavaScript;
diff --git a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowDefinitions/Execute/Endpoint.cs b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowDefinitions/Execute/Endpoint.cs
index 7ce67adc7..66f954070 100644
--- a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowDefinitions/Execute/Endpoint.cs
+++ b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowDefinitions/Execute/Endpoint.cs
@@ -2,6 +2,7 @@ using System.Net.Mime;
 using Elsa.Abstractions;
 using Elsa.Common.Models;
 using Elsa.Http.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/Get/Models.cs b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/Get/Models.cs
index f34900a19..4a03d8fcf 100644
--- a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/Get/Models.cs
+++ b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/Get/Models.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
 
diff --git a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Endpoint.cs b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Endpoint.cs
index 163e8a244..d550ebb69 100644
--- a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Endpoint.cs
+++ b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Endpoint.cs
@@ -2,6 +2,7 @@ using Elsa.Abstractions;
 using Elsa.Common.Entities;
 using Elsa.Common.Models;
 using Elsa.Workflows.Api.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Contracts;
 using Elsa.Workflows.Management.Filters;
diff --git a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Models.cs b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Models.cs
index 979f0d303..f0ca67c6a 100644
--- a/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Models.cs
+++ b/src/modules/Elsa.Workflows.Api/Endpoints/WorkflowInstances/List/Models.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Entities;
 using Elsa.Workflows.Api.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Models;
 
diff --git a/src/modules/Elsa.Workflows.Core/Models/Activity.cs b/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
similarity index 96%
rename from src/modules/Elsa.Workflows.Core/Models/Activity.cs
rename to src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
index 389988513..bdb4cfbe1 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Activity.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/Activity.cs
@@ -4,8 +4,9 @@ using Elsa.Extensions;
 using Elsa.Workflows.Core.Behaviors;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
+using Elsa.Workflows.Core.Models;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Base class for custom activities.
@@ -58,7 +59,7 @@ public abstract class Activity : IActivity, ISignalHandler
 
     /// <summary>
     /// A flag indicating if this activity should execute synchronously or asynchronously.
-    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Workflows.Core.Models.ActivityKind.Action"/>, <see cref="Workflows.Core.Models.ActivityKind.Task"/> or <see cref="Workflows.Core.Models.ActivityKind.Trigger"/>
+    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Action"/>, <see cref="Task"/> or <see cref="Trigger"/>
     /// will execute synchronously, while activities of the <see cref="Workflows.Core.Models.ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
     [JsonIgnore]
diff --git a/src/modules/Elsa.Workflows.Core/Models/ActivityT.cs b/src/modules/Elsa.Workflows.Core/Abstractions/ActivityT.cs
similarity index 94%
rename from src/modules/Elsa.Workflows.Core/Models/ActivityT.cs
rename to src/modules/Elsa.Workflows.Core/Abstractions/ActivityT.cs
index 58e668754..48559c3fe 100644
--- a/src/modules/Elsa.Workflows.Core/Models/ActivityT.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/ActivityT.cs
@@ -1,7 +1,8 @@
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Base class for custom activities that return a result.
diff --git a/src/modules/Elsa.Workflows.Core/Models/Behavior.cs b/src/modules/Elsa.Workflows.Core/Abstractions/Behavior.cs
similarity index 96%
rename from src/modules/Elsa.Workflows.Core/Models/Behavior.cs
rename to src/modules/Elsa.Workflows.Core/Abstractions/Behavior.cs
index 2dcfe70da..a3d3e4405 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Behavior.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/Behavior.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 public abstract class Behavior : IBehavior
 {
diff --git a/src/modules/Elsa.Workflows.Core/Models/CodeActivity.cs b/src/modules/Elsa.Workflows.Core/Abstractions/CodeActivity.cs
similarity index 97%
rename from src/modules/Elsa.Workflows.Core/Models/CodeActivity.cs
rename to src/modules/Elsa.Workflows.Core/Abstractions/CodeActivity.cs
index 488f8eb11..00a7caebe 100644
--- a/src/modules/Elsa.Workflows.Core/Models/CodeActivity.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/CodeActivity.cs
@@ -3,9 +3,10 @@ using Elsa.Extensions;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Behaviors;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Base class for custom activities with auto-complete behavior.
diff --git a/src/modules/Elsa.Workflows.Core/Models/Trigger.cs b/src/modules/Elsa.Workflows.Core/Abstractions/Trigger.cs
similarity index 98%
rename from src/modules/Elsa.Workflows.Core/Models/Trigger.cs
rename to src/modules/Elsa.Workflows.Core/Abstractions/Trigger.cs
index 90254586a..a1a2a772b 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Trigger.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/Trigger.cs
@@ -1,6 +1,6 @@
 using Elsa.Workflows.Core.Contracts;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Represents an activity that acts as a workflow trigger.
diff --git a/src/modules/Elsa.Workflows.Core/Abstractions/WorkflowBase.cs b/src/modules/Elsa.Workflows.Core/Abstractions/WorkflowBase.cs
index 6e4a0a5b9..400513699 100644
--- a/src/modules/Elsa.Workflows.Core/Abstractions/WorkflowBase.cs
+++ b/src/modules/Elsa.Workflows.Core/Abstractions/WorkflowBase.cs
@@ -1,4 +1,5 @@
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Abstractions;
diff --git a/src/modules/Elsa.Workflows.Core/Activities/Composite.cs b/src/modules/Elsa.Workflows.Core/Activities/Composite.cs
index 4b60cfcba..d9b3fef79 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/Composite.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/Composite.cs
@@ -6,6 +6,7 @@ using Elsa.Extensions;
 using Elsa.Workflows.Core.Activities.Flowchart.Models;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Signals;
 using JetBrains.Annotations;
diff --git a/src/modules/Elsa.Workflows.Core/Activities/Container.cs b/src/modules/Elsa.Workflows.Core/Activities/Container.cs
index 104f3c421..99bbf5020 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/Container.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/Container.cs
@@ -1,6 +1,7 @@
 using System.Collections.ObjectModel;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Activities;
diff --git a/src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs b/src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs
index 9dd5f515f..1186ef885 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs
@@ -3,6 +3,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
diff --git a/src/modules/Elsa.Workflows.Core/Activities/SetVariable.cs b/src/modules/Elsa.Workflows.Core/Activities/SetVariable.cs
index 972eb8d96..713e14ad5 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/SetVariable.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/SetVariable.cs
@@ -4,6 +4,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
diff --git a/src/modules/Elsa.Workflows.Core/Models/Workflow.cs b/src/modules/Elsa.Workflows.Core/Activities/Workflow.cs
similarity index 99%
rename from src/modules/Elsa.Workflows.Core/Models/Workflow.cs
rename to src/modules/Elsa.Workflows.Core/Activities/Workflow.cs
index 93672d8d6..4f053d25a 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Workflow.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/Workflow.cs
@@ -3,6 +3,7 @@ using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using JetBrains.Annotations;
 
 namespace Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Workflows.Core/Activities/WriteLine.cs b/src/modules/Elsa.Workflows.Core/Activities/WriteLine.cs
index 6affd8fd2..373bae576 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/WriteLine.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/WriteLine.cs
@@ -4,6 +4,7 @@ using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 
diff --git a/src/modules/Elsa.Workflows.Core/Attributes/JsonIgnoreCompositeRootAttribute.cs b/src/modules/Elsa.Workflows.Core/Attributes/JsonIgnoreCompositeRootAttribute.cs
index fb818ecfc..7872e9aad 100644
--- a/src/modules/Elsa.Workflows.Core/Attributes/JsonIgnoreCompositeRootAttribute.cs
+++ b/src/modules/Elsa.Workflows.Core/Attributes/JsonIgnoreCompositeRootAttribute.cs
@@ -1,7 +1,9 @@
+using Elsa.Workflows.Core.Serialization.Converters;
+
 namespace Elsa.Workflows.Core.Attributes;
 
 /// <summary>
-/// Used by <see cref="JsonIgnoreCompositeRootConverter{T}"/> to indicate that the property should be expanded into a JSON object.
+/// Used by <see cref="JsonIgnoreCompositeRootConverter"/> to indicate that the property should be expanded into a JSON object.
 /// </summary>
 [AttributeUsage(AttributeTargets.Property)]
 public class JsonIgnoreCompositeRootAttribute : Attribute
diff --git a/src/modules/Elsa.Workflows.Core/Builders/WorkflowBuilder.cs b/src/modules/Elsa.Workflows.Core/Builders/WorkflowBuilder.cs
index d3b390dd4..aa71e344b 100644
--- a/src/modules/Elsa.Workflows.Core/Builders/WorkflowBuilder.cs
+++ b/src/modules/Elsa.Workflows.Core/Builders/WorkflowBuilder.cs
@@ -1,6 +1,7 @@
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Builders;
diff --git a/src/modules/Elsa.Workflows.Core/Models/ActivityExecutionContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
similarity index 77%
rename from src/modules/Elsa.Workflows.Core/Models/ActivityExecutionContext.cs
rename to src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
index 73532556c..0e36d8fc1 100644
--- a/src/modules/Elsa.Workflows.Core/Models/ActivityExecutionContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contexts/ActivityExecutionContext.cs
@@ -4,9 +4,11 @@ using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
+using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Represents the context of an activity execution.
@@ -73,6 +75,8 @@ public class ActivityExecutionContext : IExecutionContext
     /// A cancellation token to use when invoking asynchronous operations.
     /// </summary>
     public CancellationToken CancellationToken { get; }
+
+    public ActivityStatus Status { get; set; }
     
     /// <inheritdoc />
     public IDictionary<string, object> Properties { get; set; } = new Dictionary<string, object>();
@@ -126,23 +130,49 @@ public class ActivityExecutionContext : IExecutionContext
     /// </summary>
     public IDictionary<string, object> ActivityState { get; set; } = new Dictionary<string, object>();
 
+    /// <summary>
+    /// Schedules the specified activity to be executed.
+    /// </summary>
+    /// <param name="activity">The activity to schedule.</param>
+    /// <param name="completionCallback">An optional callback that is invoked when the activity completes.</param>
+    /// <param name="tag">An optional tag that can be used to identify the activity.</param>
     public async ValueTask ScheduleActivityAsync(IActivity? activity, ActivityCompletionCallback? completionCallback = default, object? tag = default)
     {
         var activityNode = activity != null ? WorkflowExecutionContext.FindNodeByActivity(activity) : default;
         await ScheduleActivityAsync(activityNode, completionCallback, tag);
     }
     
+    /// <summary>
+    /// Schedules the specified activity to be executed.
+    /// </summary>
+    /// <param name="activity">The activity to schedule.</param>
+    /// <param name="owner">The activity execution context that owns the activity.</param>
+    /// <param name="completionCallback">An optional callback that is invoked when the activity completes.</param>
+    /// <param name="tag">An optional tag that can be used to identify the activity.</param>
     public async ValueTask ScheduleActivityAsync(IActivity? activity, ActivityExecutionContext owner, ActivityCompletionCallback? completionCallback = default, object? tag = default)
     {
         var activityNode = activity != null ? WorkflowExecutionContext.FindNodeByActivity(activity) : default;
         await ScheduleActivityAsync(activityNode, this, completionCallback, tag);
     }
     
+    /// <summary>
+    /// Schedules the specified activity to be executed.
+    /// </summary>
+    /// <param name="activityNode">The activity node to schedule.</param>
+    /// <param name="completionCallback">An optional callback that is invoked when the activity completes.</param>
+    /// <param name="tag">An optional tag that can be used to identify the activity.</param>
     public async ValueTask ScheduleActivityAsync(ActivityNode? activityNode, ActivityCompletionCallback? completionCallback = default, object? tag = default)
     {
         await ScheduleActivityAsync(activityNode, this, completionCallback, tag);
     }
 
+    /// <summary>
+    /// Schedules the specified activity to be executed.
+    /// </summary>
+    /// <param name="activityNode">The activity node to schedule.</param>
+    /// <param name="owner">The activity execution context that owns the activity.</param>
+    /// <param name="completionCallback">An optional callback that is invoked when the activity completes.</param>
+    /// <param name="tag">An optional tag that can be used to identify the activity.</param>
     public async ValueTask ScheduleActivityAsync(ActivityNode? activityNode, ActivityExecutionContext owner, ActivityCompletionCallback? completionCallback = default, object? tag = default)
     {
         if (activityNode == null)
@@ -157,25 +187,67 @@ public class ActivityExecutionContext : IExecutionContext
         WorkflowExecutionContext.Schedule(activityNode, owner, completionCallback, tag);
     }
 
+    /// <summary>
+    /// Schedules the specified activities to be executed.
+    /// </summary>
+    /// <param name="activities">The activities to schedule.</param>
     public async ValueTask ScheduleActivitiesAsync(params IActivity?[] activities) => await ScheduleActivities(activities);
 
+    /// <summary>
+    /// Schedules the specified activities to be executed.
+    /// </summary>
+    /// <param name="activities">The activities to schedule.</param>
+    /// <param name="completionCallback">An optional callback that is invoked for each activity when it completes.</param>
     public async ValueTask ScheduleActivities(IEnumerable<IActivity?> activities, ActivityCompletionCallback? completionCallback = default)
     {
         foreach (var activity in activities)
             await ScheduleActivityAsync(activity, completionCallback);
     }
 
+    /// <summary>
+    /// Creates a bookmark for each payload.
+    /// </summary>
+    /// <param name="payloads">The payloads to create bookmarks for.</param>
+    /// <param name="callback">An optional callback that is invoked when the bookmark is resumed.</param>
     public void CreateBookmarks(IEnumerable<object> payloads, ExecuteActivityDelegate? callback = default)
     {
         foreach (var payload in payloads)
             CreateBookmark(new BookmarkOptions(payload, callback));
     }
 
+    /// <summary>
+    /// Adds each bookmark to the list of bookmarks.
+    /// </summary>
+    /// <param name="bookmarks">The bookmarks to add.</param>
     public void AddBookmarks(IEnumerable<Bookmark> bookmarks) => _bookmarks.AddRange(bookmarks);
+    
+    /// <summary>
+    /// Adds a bookmark to the list of bookmarks.
+    /// </summary>
+    /// <param name="bookmark">The bookmark to add.</param>
     public void AddBookmark(Bookmark bookmark) => _bookmarks.Add(bookmark);
 
+    /// <summary>
+    /// Creates a bookmark so that this activity can be resumed at a later time.
+    /// </summary>
+    /// <param name="callback">An optional callback that is invoked when the bookmark is resumed.</param>
+    /// <returns>The created bookmark.</returns>
     public Bookmark CreateBookmark(ExecuteActivityDelegate callback) => CreateBookmark(new BookmarkOptions(default, callback));
+    
+    
+    /// <summary>
+    /// Creates a bookmark so that this activity can be resumed at a later time.
+    /// </summary>
+    /// <param name="payload">The payload to associate with the bookmark.</param>
+    /// <param name="callback">An optional callback that is invoked when the bookmark is resumed.</param>
+    /// <returns>The created bookmark.</returns>
     public Bookmark CreateBookmark(object payload, ExecuteActivityDelegate callback) => CreateBookmark(new BookmarkOptions(payload, callback));
+    
+    /// <summary>
+    /// Creates a bookmark so that this activity can be resumed at a later time. 
+    /// </summary>
+    /// <param name="payload">The payload to associate with the bookmark.</param>
+    /// <returns>The created bookmark.</returns>
     public Bookmark CreateBookmark(object payload) => CreateBookmark(new BookmarkOptions(payload));
 
     /// <summary>
diff --git a/src/modules/Elsa.Workflows.Core/Contexts/ResumedBookmarkContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/ResumedBookmarkContext.cs
new file mode 100644
index 000000000..047c6657f
--- /dev/null
+++ b/src/modules/Elsa.Workflows.Core/Contexts/ResumedBookmarkContext.cs
@@ -0,0 +1,5 @@
+using Elsa.Workflows.Core.Models;
+
+namespace Elsa.Workflows.Core;
+
+public record ResumedBookmarkContext(Bookmark Bookmark);
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Models/TriggerIndexingContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/TriggerIndexingContext.cs
similarity index 92%
rename from src/modules/Elsa.Workflows.Core/Models/TriggerIndexingContext.cs
rename to src/modules/Elsa.Workflows.Core/Contexts/TriggerIndexingContext.cs
index 6e0faed95..bfec84e7c 100644
--- a/src/modules/Elsa.Workflows.Core/Models/TriggerIndexingContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contexts/TriggerIndexingContext.cs
@@ -1,8 +1,9 @@
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 public class TriggerIndexingContext
 {
diff --git a/src/modules/Elsa.Workflows.Core/Models/WorkflowExecutionContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/WorkflowExecutionContext.cs
similarity index 99%
rename from src/modules/Elsa.Workflows.Core/Models/WorkflowExecutionContext.cs
rename to src/modules/Elsa.Workflows.Core/Contexts/WorkflowExecutionContext.cs
index ecaf8508a..09a1b7555 100644
--- a/src/modules/Elsa.Workflows.Core/Models/WorkflowExecutionContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contexts/WorkflowExecutionContext.cs
@@ -5,9 +5,11 @@ using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Services;
 using Microsoft.Extensions.DependencyInjection;
 using System.Collections.ObjectModel;
+using Elsa.Workflows.Core.Memory;
+using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// A delegate entry that is used by activities to be notified when the activities they scheduled are completed.
diff --git a/src/modules/Elsa.Workflows.Core/Models/WorkflowIndexingContext.cs b/src/modules/Elsa.Workflows.Core/Contexts/WorkflowIndexingContext.cs
similarity index 92%
rename from src/modules/Elsa.Workflows.Core/Models/WorkflowIndexingContext.cs
rename to src/modules/Elsa.Workflows.Core/Contexts/WorkflowIndexingContext.cs
index 0dd66b3ad..56e4c1e90 100644
--- a/src/modules/Elsa.Workflows.Core/Models/WorkflowIndexingContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contexts/WorkflowIndexingContext.cs
@@ -1,7 +1,8 @@
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 public class WorkflowIndexingContext
 {
diff --git a/src/modules/Elsa.Workflows.Core/Contracts/IExecutionContext.cs b/src/modules/Elsa.Workflows.Core/Contracts/IExecutionContext.cs
index ed01fbb55..35ff9457c 100644
--- a/src/modules/Elsa.Workflows.Core/Contracts/IExecutionContext.cs
+++ b/src/modules/Elsa.Workflows.Core/Contracts/IExecutionContext.cs
@@ -1,4 +1,5 @@
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Workflows.Core/Contracts/IVariableContainer.cs b/src/modules/Elsa.Workflows.Core/Contracts/IVariableContainer.cs
index b26b34d63..d487ae10b 100644
--- a/src/modules/Elsa.Workflows.Core/Contracts/IVariableContainer.cs
+++ b/src/modules/Elsa.Workflows.Core/Contracts/IVariableContainer.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowBuilder.cs b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowBuilder.cs
index 8280ad733..4d0895311 100644
--- a/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowBuilder.cs
+++ b/src/modules/Elsa.Workflows.Core/Contracts/IWorkflowBuilder.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Contracts;
diff --git a/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj b/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj
index 2017f4352..42dff073b 100644
--- a/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj
+++ b/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj
@@ -29,4 +29,8 @@
         <ProjectReference Include="..\Elsa.Mediator\Elsa.Mediator.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+      <Folder Include="Bookmarks\" />
+    </ItemGroup>
+
 </Project>
diff --git a/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj.DotSettings b/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj.DotSettings
index 72387db01..d55c6dda2 100644
--- a/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj.DotSettings
+++ b/src/modules/Elsa.Workflows.Core/Elsa.Workflows.Core.csproj.DotSettings
@@ -1,4 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=abstractions/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Ccontainers_005Cfreeflowchart/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Ccontrolflow_005Cfinish/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Ccontrolflow_005Cfor/@EntryIndexedValue">True</s:Boolean>
@@ -6,4 +7,6 @@
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Cprimitives_005Csetname/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Csignaling_005Cactivities_005Csignalreceived/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=activities_005Cworkflows_005Cfreeflowchart/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=contexts/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=enums/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=extensions/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Models/ActivityKind.cs b/src/modules/Elsa.Workflows.Core/Enums/ActivityKind.cs
similarity index 93%
rename from src/modules/Elsa.Workflows.Core/Models/ActivityKind.cs
rename to src/modules/Elsa.Workflows.Core/Enums/ActivityKind.cs
index c1f6894df..f86b894fc 100644
--- a/src/modules/Elsa.Workflows.Core/Models/ActivityKind.cs
+++ b/src/modules/Elsa.Workflows.Core/Enums/ActivityKind.cs
@@ -1,4 +1,4 @@
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Represents the kind of an activity, which affects how it is executed.
diff --git a/src/modules/Elsa.Workflows.Core/Enums/ActivityStatus.cs b/src/modules/Elsa.Workflows.Core/Enums/ActivityStatus.cs
new file mode 100644
index 000000000..fe33ff4da
--- /dev/null
+++ b/src/modules/Elsa.Workflows.Core/Enums/ActivityStatus.cs
@@ -0,0 +1,17 @@
+namespace Elsa.Workflows.Core.Models;
+
+/// <summary>
+/// Represents the status of an activity.
+/// </summary>
+public enum ActivityStatus
+{
+    /// <summary>
+    /// The activity is in the Running state. Note that event if an activity is running, it may not be executing.
+    /// </summary>
+    Running,
+    
+    /// <summary>
+    /// The activity is in the Completed state.
+    /// </summary>
+    Completed,
+}
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Enums/SwitchMode.cs b/src/modules/Elsa.Workflows.Core/Enums/SwitchMode.cs
new file mode 100644
index 000000000..71bfd0dca
--- /dev/null
+++ b/src/modules/Elsa.Workflows.Core/Enums/SwitchMode.cs
@@ -0,0 +1,17 @@
+namespace Elsa.Workflows.Core;
+
+/// <summary>
+/// Represents the switch mode.
+/// </summary>
+public enum SwitchMode
+{
+    /// <summary>
+    /// Yields the outcome of the first condition evaluating to true.
+    /// </summary>
+    MatchFirst,
+
+    /// <summary>
+    /// Yields the outcome of all conditions evaluating to true.
+    /// </summary>
+    MatchAny
+}
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Models/TypeKind.cs b/src/modules/Elsa.Workflows.Core/Enums/TypeKind.cs
similarity index 56%
rename from src/modules/Elsa.Workflows.Core/Models/TypeKind.cs
rename to src/modules/Elsa.Workflows.Core/Enums/TypeKind.cs
index 53eb786d5..1b6d169f4 100644
--- a/src/modules/Elsa.Workflows.Core/Models/TypeKind.cs
+++ b/src/modules/Elsa.Workflows.Core/Enums/TypeKind.cs
@@ -1,5 +1,8 @@
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
+/// <summary>
+/// Represents the switch mode.
+/// </summary>
 [Flags]
 public enum TypeKind
 {
diff --git a/src/modules/Elsa.Workflows.Core/Models/WorkflowStatus.cs b/src/modules/Elsa.Workflows.Core/Enums/WorkflowStatus.cs
similarity index 90%
rename from src/modules/Elsa.Workflows.Core/Models/WorkflowStatus.cs
rename to src/modules/Elsa.Workflows.Core/Enums/WorkflowStatus.cs
index 6f7ced687..707bccd39 100644
--- a/src/modules/Elsa.Workflows.Core/Models/WorkflowStatus.cs
+++ b/src/modules/Elsa.Workflows.Core/Enums/WorkflowStatus.cs
@@ -1,4 +1,4 @@
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Represents the current workflow status.
diff --git a/src/modules/Elsa.Workflows.Core/Models/WorkflowSubStatus.cs b/src/modules/Elsa.Workflows.Core/Enums/WorkflowSubStatus.cs
similarity index 94%
rename from src/modules/Elsa.Workflows.Core/Models/WorkflowSubStatus.cs
rename to src/modules/Elsa.Workflows.Core/Enums/WorkflowSubStatus.cs
index b53bd3be4..a4fd18acb 100644
--- a/src/modules/Elsa.Workflows.Core/Models/WorkflowSubStatus.cs
+++ b/src/modules/Elsa.Workflows.Core/Enums/WorkflowSubStatus.cs
@@ -1,4 +1,4 @@
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core;
 
 /// <summary>
 /// Represents the workflow sub-status.
diff --git a/src/modules/Elsa.Workflows.Core/Expressions/VariableExpression.cs b/src/modules/Elsa.Workflows.Core/Expressions/VariableExpression.cs
index 135037ade..c4d44a4da 100644
--- a/src/modules/Elsa.Workflows.Core/Expressions/VariableExpression.cs
+++ b/src/modules/Elsa.Workflows.Core/Expressions/VariableExpression.cs
@@ -1,5 +1,6 @@
 using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Expressions;
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/ActivityExecutionContextExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/ActivityExecutionContextExtensions.cs
index 1cada9d6b..56cc46394 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/ActivityExecutionContextExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/ActivityExecutionContextExtensions.cs
@@ -7,9 +7,11 @@ using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities.Flowchart.Models;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Notifications;
 using Elsa.Workflows.Core.Signals;
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
index c085429bd..983ed0f92 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/ActivityPropertyExtensions.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 
 // ReSharper disable once CheckNamespace
@@ -25,14 +26,14 @@ public static class ActivityPropertyExtensions
 
     /// <summary>
     /// Gets a flag indicating if this activity should execute synchronously or asynchronously.
-    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Workflows.Core.Models.ActivityKind.Action"/>, <see cref="Workflows.Core.Models.ActivityKind.Task"/> or <see cref="Workflows.Core.Models.ActivityKind.Trigger"/>
+    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Action"/>, <see cref="Task"/> or <see cref="Trigger"/>
     /// will execute synchronously, while activities of the <see cref="Workflows.Core.Models.ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
     public static bool GetRunAsynchronously(this IActivity activity) => activity.CustomProperties.GetValueOrDefault(RunAsynchronouslyPropertyName, () => false);
 
     /// <summary>
     /// Sets a flag indicating if this activity should execute synchronously or asynchronously.
-    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Workflows.Core.Models.ActivityKind.Action"/>, <see cref="Workflows.Core.Models.ActivityKind.Task"/> or <see cref="Workflows.Core.Models.ActivityKind.Trigger"/>
+    /// By default, activities with an <see cref="Workflows.Core.Models.ActivityKind"/> of <see cref="Action"/>, <see cref="Task"/> or <see cref="Trigger"/>
     /// will execute synchronously, while activities of the <see cref="Workflows.Core.Models.ActivityKind.Job"/> kind will execute asynchronously.
     /// </summary>
     public static void SetRunAsynchronously(this IActivity activity, bool value) => activity.CustomProperties[RunAsynchronouslyPropertyName[0]] = value;
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/ExpressionExecutionContextExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/ExpressionExecutionContextExtensions.cs
index c315a022d..10e0608d8 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/ExpressionExecutionContextExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/ExpressionExecutionContextExtensions.cs
@@ -1,5 +1,7 @@
 using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/InputExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/InputExtensions.cs
index 515123992..fcdece0fd 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/InputExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/InputExtensions.cs
@@ -1,5 +1,6 @@
 using System.Runtime.CompilerServices;
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/MemoryBlockReferenceExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/MemoryBlockReferenceExtensions.cs
index 758f95272..ed57d9f85 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/MemoryBlockReferenceExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/MemoryBlockReferenceExtensions.cs
@@ -1,5 +1,6 @@
 using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/OutputExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/OutputExtensions.cs
index 5cbaf6fd0..8ae49b51d 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/OutputExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/OutputExtensions.cs
@@ -1,4 +1,6 @@
 using Elsa.Expressions.Models;
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/TriggerExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/TriggerExtensions.cs
index 2dbb29a1c..acd2c4f45 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/TriggerExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/TriggerExtensions.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/VariableCollectionExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/VariableCollectionExtensions.cs
index 2122e9c75..b6559a5d1 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/VariableCollectionExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/VariableCollectionExtensions.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 // ReSharper disable once CheckNamespace
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/VariableExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/VariableExtensions.cs
index 885b06132..c18ca9d18 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/VariableExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/VariableExtensions.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using Elsa.Expressions.Helpers;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Serialization.Converters;
 using Elsa.Workflows.Core.Services;
diff --git a/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
index c9c03811c..cd2741be0 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
diff --git a/src/modules/Elsa.Workflows.Core/Models/ElsaExpressionBlockReference.cs b/src/modules/Elsa.Workflows.Core/Memory/ElsaExpressionBlockReference.cs
similarity index 90%
rename from src/modules/Elsa.Workflows.Core/Models/ElsaExpressionBlockReference.cs
rename to src/modules/Elsa.Workflows.Core/Memory/ElsaExpressionBlockReference.cs
index cca544e0c..6bc374ec3 100644
--- a/src/modules/Elsa.Workflows.Core/Models/ElsaExpressionBlockReference.cs
+++ b/src/modules/Elsa.Workflows.Core/Memory/ElsaExpressionBlockReference.cs
@@ -1,7 +1,7 @@
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Expressions;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core.Memory;
 
 public class ElsaExpressionBlockReference : MemoryBlockReference
 {
diff --git a/src/modules/Elsa.Workflows.Core/Models/Variable.cs b/src/modules/Elsa.Workflows.Core/Memory/Variable.cs
similarity index 97%
rename from src/modules/Elsa.Workflows.Core/Models/Variable.cs
rename to src/modules/Elsa.Workflows.Core/Memory/Variable.cs
index 7212d3236..17a897027 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Variable.cs
+++ b/src/modules/Elsa.Workflows.Core/Memory/Variable.cs
@@ -2,7 +2,7 @@ using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Contracts;
 
-namespace Elsa.Workflows.Core.Models;
+namespace Elsa.Workflows.Core.Memory;
 
 public class Variable : MemoryBlockReference
 {
diff --git a/src/modules/Elsa.Workflows.Core/Models/Input.cs b/src/modules/Elsa.Workflows.Core/Models/Input.cs
index 3e4aaf38f..076c50f8f 100644
--- a/src/modules/Elsa.Workflows.Core/Models/Input.cs
+++ b/src/modules/Elsa.Workflows.Core/Models/Input.cs
@@ -3,6 +3,7 @@ using Elsa.Expressions;
 using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Expressions;
+using Elsa.Workflows.Core.Memory;
 
 namespace Elsa.Workflows.Core.Models;
 
diff --git a/src/modules/Elsa.Workflows.Core/Models/ResumedBookmarkContext.cs b/src/modules/Elsa.Workflows.Core/Models/ResumedBookmarkContext.cs
deleted file mode 100644
index 06edad5d4..000000000
--- a/src/modules/Elsa.Workflows.Core/Models/ResumedBookmarkContext.cs
+++ /dev/null
@@ -1,3 +0,0 @@
-namespace Elsa.Workflows.Core.Models;
-
-public record ResumedBookmarkContext(Bookmark Bookmark);
\ No newline at end of file
diff --git a/src/modules/Elsa.Workflows.Core/Models/SwitchMode.cs b/src/modules/Elsa.Workflows.Core/Models/SwitchMode.cs
deleted file mode 100644
index f25aa3cf9..000000000
--- a/src/modules/Elsa.Workflows.Core/Models/SwitchMode.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-namespace Elsa.Workflows.Core.Models
-{
-    public enum SwitchMode
-    {
-        /// <summary>
-        /// Yields the outcome of the first condition evaluating to true.
-        /// </summary>
-        MatchFirst,
-
-        /// <summary>
-        /// Yields the outcome of all conditions evaluating to true.
-        /// </summary>
-        MatchAny
-    }
-}
diff --git a/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverter.cs b/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverter.cs
index 1b7067f81..e263d7748 100644
--- a/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverter.cs
+++ b/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverter.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 using Microsoft.Extensions.Logging;
diff --git a/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverterFactory.cs b/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverterFactory.cs
index f6fc9129d..e0a21b969 100644
--- a/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverterFactory.cs
+++ b/src/modules/Elsa.Workflows.Core/Serialization/Converters/VariableConverterFactory.cs
@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 using Microsoft.Extensions.Logging;
diff --git a/src/modules/Elsa.Workflows.Core/Services/ActivityDescriber.cs b/src/modules/Elsa.Workflows.Core/Services/ActivityDescriber.cs
index c61d491d2..48a4789c8 100644
--- a/src/modules/Elsa.Workflows.Core/Services/ActivityDescriber.cs
+++ b/src/modules/Elsa.Workflows.Core/Services/ActivityDescriber.cs
@@ -7,6 +7,7 @@ using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Humanizer;
 
diff --git a/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs b/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
index 8fc1ea81e..ff967092d 100644
--- a/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
+++ b/src/modules/Elsa.Workflows.Core/Services/VariableMapper.cs
@@ -3,6 +3,7 @@ using Elsa.Expressions.Extensions;
 using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Services;
 using Elsa.Extensions;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
diff --git a/src/modules/Elsa.Workflows.Core/Services/VariablePersistenceManager.cs b/src/modules/Elsa.Workflows.Core/Services/VariablePersistenceManager.cs
index 1b5f5f8e6..c69a5dca6 100644
--- a/src/modules/Elsa.Workflows.Core/Services/VariablePersistenceManager.cs
+++ b/src/modules/Elsa.Workflows.Core/Services/VariablePersistenceManager.cs
@@ -1,6 +1,7 @@
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Core.Services;
diff --git a/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivity.cs b/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivity.cs
index 69c918cdf..f3d648a7d 100644
--- a/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivity.cs
+++ b/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivity.cs
@@ -1,8 +1,10 @@
 using System.ComponentModel;
 using Elsa.Common.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Signals;
 using Elsa.Workflows.Management.Contracts;
diff --git a/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivityProvider.cs b/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivityProvider.cs
index bc39bb41e..bb4bad523 100644
--- a/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivityProvider.cs
+++ b/src/modules/Elsa.Workflows.Management/Activities/WorkflowDefinitionActivity/WorkflowDefinitionActivityProvider.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Contracts;
diff --git a/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs b/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
index ad6fcc8c2..8e2e20255 100644
--- a/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
+++ b/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
@@ -1,4 +1,5 @@
 using Elsa.Common.Entities;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Management.Entities;
diff --git a/src/modules/Elsa.Workflows.Management/Entities/WorkflowInstance.cs b/src/modules/Elsa.Workflows.Management/Entities/WorkflowInstance.cs
index d9a65183e..b82d33fdd 100644
--- a/src/modules/Elsa.Workflows.Management/Entities/WorkflowInstance.cs
+++ b/src/modules/Elsa.Workflows.Management/Entities/WorkflowInstance.cs
@@ -1,4 +1,5 @@
 using Elsa.Common.Entities;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
 
diff --git a/src/modules/Elsa.Workflows.Management/Filters/WorkflowInstanceFilter.cs b/src/modules/Elsa.Workflows.Management/Filters/WorkflowInstanceFilter.cs
index 92a24a1ab..ac59c1e82 100644
--- a/src/modules/Elsa.Workflows.Management/Filters/WorkflowInstanceFilter.cs
+++ b/src/modules/Elsa.Workflows.Management/Filters/WorkflowInstanceFilter.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Entities;
 
diff --git a/src/modules/Elsa.Workflows.Management/Mappers/VariableDefinitionMapper.cs b/src/modules/Elsa.Workflows.Management/Mappers/VariableDefinitionMapper.cs
index 8e98545db..cc88799cb 100644
--- a/src/modules/Elsa.Workflows.Management/Mappers/VariableDefinitionMapper.cs
+++ b/src/modules/Elsa.Workflows.Management/Mappers/VariableDefinitionMapper.cs
@@ -2,6 +2,7 @@ using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Extensions;
 using Elsa.Expressions.Helpers;
 using Elsa.Extensions;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Management.Mappers;
diff --git a/src/modules/Elsa.Workflows.Management/Models/WorkflowInstanceSummary.cs b/src/modules/Elsa.Workflows.Management/Models/WorkflowInstanceSummary.cs
index f3d87046b..050804e10 100644
--- a/src/modules/Elsa.Workflows.Management/Models/WorkflowInstanceSummary.cs
+++ b/src/modules/Elsa.Workflows.Management/Models/WorkflowInstanceSummary.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Entities;
 using JetBrains.Annotations;
diff --git a/src/modules/Elsa.Workflows.Management/Providers/DefaultExpressionSyntaxProvider.cs b/src/modules/Elsa.Workflows.Management/Providers/DefaultExpressionSyntaxProvider.cs
index fb653845c..5e3a21941 100644
--- a/src/modules/Elsa.Workflows.Management/Providers/DefaultExpressionSyntaxProvider.cs
+++ b/src/modules/Elsa.Workflows.Management/Providers/DefaultExpressionSyntaxProvider.cs
@@ -3,6 +3,7 @@ using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Expressions;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Management.Providers;
diff --git a/src/modules/Elsa.Workflows.Management/Serialization/Converters/ActivityJsonConverter.cs b/src/modules/Elsa.Workflows.Management/Serialization/Converters/ActivityJsonConverter.cs
index 1f9466067..6fdd6396e 100644
--- a/src/modules/Elsa.Workflows.Management/Serialization/Converters/ActivityJsonConverter.cs
+++ b/src/modules/Elsa.Workflows.Management/Serialization/Converters/ActivityJsonConverter.cs
@@ -6,6 +6,7 @@ using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Humanizer;
 
diff --git a/src/modules/Elsa.Workflows.Management/Serialization/Converters/OutputJsonConverter.cs b/src/modules/Elsa.Workflows.Management/Serialization/Converters/OutputJsonConverter.cs
index 404b3d171..8848bd030 100644
--- a/src/modules/Elsa.Workflows.Management/Serialization/Converters/OutputJsonConverter.cs
+++ b/src/modules/Elsa.Workflows.Management/Serialization/Converters/OutputJsonConverter.cs
@@ -2,6 +2,7 @@ using System.Text.Json;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Extensions;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Management.Serialization.Converters;
diff --git a/src/modules/Elsa.Workflows.Runtime/Activities/Event.cs b/src/modules/Elsa.Workflows.Runtime/Activities/Event.cs
index b14d317ea..a1fc5a3cd 100644
--- a/src/modules/Elsa.Workflows.Runtime/Activities/Event.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Activities/Event.cs
@@ -2,7 +2,9 @@ using System.Runtime.CompilerServices;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using JetBrains.Annotations;
 
diff --git a/src/modules/Elsa.Workflows.Runtime/Activities/PublishEvent.cs b/src/modules/Elsa.Workflows.Runtime/Activities/PublishEvent.cs
index f77868e04..e2f2ecf5f 100644
--- a/src/modules/Elsa.Workflows.Runtime/Activities/PublishEvent.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Activities/PublishEvent.cs
@@ -5,6 +5,7 @@ using Elsa.Workflows.Runtime.Contracts;
 using JetBrains.Annotations;
 using System.Runtime.CompilerServices;
 using System.Text.Json.Serialization;
+using Elsa.Workflows.Core;
 
 namespace Elsa.Workflows.Runtime.Activities;
 
diff --git a/src/modules/Elsa.Workflows.Runtime/Activities/RunTask.cs b/src/modules/Elsa.Workflows.Runtime/Activities/RunTask.cs
index c89bfbde8..3f7e8a35a 100644
--- a/src/modules/Elsa.Workflows.Runtime/Activities/RunTask.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Activities/RunTask.cs
@@ -2,8 +2,10 @@ using System.Runtime.CompilerServices;
 using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Attributes;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Runtime.Bookmarks;
 using Elsa.Workflows.Runtime.Contracts;
diff --git a/src/modules/Elsa.Workflows.Core/Models/EventBookmarkPayload.cs b/src/modules/Elsa.Workflows.Runtime/Bookmarks/EventBookmarkPayload.cs
similarity index 100%
rename from src/modules/Elsa.Workflows.Core/Models/EventBookmarkPayload.cs
rename to src/modules/Elsa.Workflows.Runtime/Bookmarks/EventBookmarkPayload.cs
diff --git a/src/modules/Elsa.Workflows.Runtime/Contracts/IBookmarksPersistedHandler.cs b/src/modules/Elsa.Workflows.Runtime/Contracts/IBookmarksPersistedHandler.cs
index e178a3ca8..439a1dcf8 100644
--- a/src/modules/Elsa.Workflows.Runtime/Contracts/IBookmarksPersistedHandler.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Contracts/IBookmarksPersistedHandler.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Runtime.Contracts;
diff --git a/src/modules/Elsa.Workflows.Runtime/Contracts/IWorkflowRuntime.cs b/src/modules/Elsa.Workflows.Runtime/Contracts/IWorkflowRuntime.cs
index 264bec08d..78293773f 100644
--- a/src/modules/Elsa.Workflows.Runtime/Contracts/IWorkflowRuntime.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Contracts/IWorkflowRuntime.cs
@@ -1,4 +1,5 @@
 using Elsa.Common.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/modules/Elsa.Workflows.Runtime/Handlers/ResumeDispatchWorkflowActivityHandler.cs b/src/modules/Elsa.Workflows.Runtime/Handlers/ResumeDispatchWorkflowActivityHandler.cs
index 6f1e3adb5..7e3d7645d 100644
--- a/src/modules/Elsa.Workflows.Runtime/Handlers/ResumeDispatchWorkflowActivityHandler.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Handlers/ResumeDispatchWorkflowActivityHandler.cs
@@ -1,4 +1,5 @@
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Notifications;
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
index 73636bbc8..9fc0ef5fb 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Activities/BackgroundActivityInvokerMiddleware.cs
@@ -1,4 +1,5 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Middleware.Activities;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.ActivityExecution;
@@ -8,7 +9,7 @@ using Elsa.Workflows.Runtime.Models.Bookmarks;
 namespace Elsa.Workflows.Runtime.Middleware.Activities;
 
 /// <summary>
-/// Executes the current activity from a background job if the activity is of kind <see cref="ActivityKind.Job"/> or <see cref="ActivityKind.Task"/>.
+/// Executes the current activity from a background job if the activity is of kind <see cref="ActivityKind.Job"/> or <see cref="Task"/>.
 /// </summary>
 public class BackgroundActivityInvokerMiddleware : DefaultActivityInvokerMiddleware
 {
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistBookmarkMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistBookmarkMiddleware.cs
index 768a7a56c..b3bc315f7 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistBookmarkMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistBookmarkMiddleware.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.WorkflowExecution;
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowExecutionLogMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowExecutionLogMiddleware.cs
index 0097524d2..33f7239e7 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowExecutionLogMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowExecutionLogMiddleware.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.WorkflowExecution;
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowStateMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowStateMiddleware.cs
index 4038abb88..88a55e2d5 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowStateMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistWorkflowStateMiddleware.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.WorkflowExecution;
diff --git a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistentVariablesMiddleware.cs b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistentVariablesMiddleware.cs
index 507248202..c6acb04cf 100644
--- a/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistentVariablesMiddleware.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Middleware/Workflows/PersistentVariablesMiddleware.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Pipelines.WorkflowExecution;
diff --git a/src/modules/Elsa.Workflows.Runtime/Notifications/RunTaskRequest.cs b/src/modules/Elsa.Workflows.Runtime/Notifications/RunTaskRequest.cs
index 387ed5671..6178cbb3f 100644
--- a/src/modules/Elsa.Workflows.Runtime/Notifications/RunTaskRequest.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Notifications/RunTaskRequest.cs
@@ -1,4 +1,5 @@
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Workflows.Runtime.Notifications;
diff --git a/src/modules/Elsa.Workflows.Runtime/Notifications/WorkflowBookmarksIndexed.cs b/src/modules/Elsa.Workflows.Runtime/Notifications/WorkflowBookmarksIndexed.cs
index da511bac8..21df9302e 100644
--- a/src/modules/Elsa.Workflows.Runtime/Notifications/WorkflowBookmarksIndexed.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Notifications/WorkflowBookmarksIndexed.cs
@@ -1,4 +1,5 @@
 using Elsa.Mediator.Contracts;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Runtime.Models.Notifications;
 
diff --git a/src/modules/Elsa.Workflows.Runtime/Services/DefaultBackgroundActivityInvoker.cs b/src/modules/Elsa.Workflows.Runtime/Services/DefaultBackgroundActivityInvoker.cs
index e00940519..d5a80d29a 100644
--- a/src/modules/Elsa.Workflows.Runtime/Services/DefaultBackgroundActivityInvoker.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Services/DefaultBackgroundActivityInvoker.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Models;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.Services;
 using Elsa.Workflows.Management.Contracts;
diff --git a/src/modules/Elsa.Workflows.Runtime/Services/MemoryWorkflowStateStore.cs b/src/modules/Elsa.Workflows.Runtime/Services/MemoryWorkflowStateStore.cs
index 68064f3b8..7e34e0b06 100644
--- a/src/modules/Elsa.Workflows.Runtime/Services/MemoryWorkflowStateStore.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Services/MemoryWorkflowStateStore.cs
@@ -1,4 +1,5 @@
 using System.Collections.Concurrent;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
 using Elsa.Workflows.Runtime.Contracts;
diff --git a/src/modules/Elsa.Workflows.Runtime/Services/TriggerIndexer.cs b/src/modules/Elsa.Workflows.Runtime/Services/TriggerIndexer.cs
index 9462582fc..939adfdd8 100644
--- a/src/modules/Elsa.Workflows.Runtime/Services/TriggerIndexer.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Services/TriggerIndexer.cs
@@ -2,6 +2,7 @@ using System.Runtime.CompilerServices;
 using Elsa.Expressions.Contracts;
 using Elsa.Expressions.Models;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Workflows.Runtime/Services/WorkflowHost.cs b/src/modules/Elsa.Workflows.Runtime/Services/WorkflowHost.cs
index 54232923e..727a81618 100644
--- a/src/modules/Elsa.Workflows.Runtime/Services/WorkflowHost.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Services/WorkflowHost.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Helpers;
 using Elsa.Workflows.Core.Models;
diff --git a/src/modules/Elsa.Workflows.Runtime/Services/WorkflowInstanceFactory.cs b/src/modules/Elsa.Workflows.Runtime/Services/WorkflowInstanceFactory.cs
index e161f881e..d31428eb7 100644
--- a/src/modules/Elsa.Workflows.Runtime/Services/WorkflowInstanceFactory.cs
+++ b/src/modules/Elsa.Workflows.Runtime/Services/WorkflowInstanceFactory.cs
@@ -1,5 +1,6 @@
 using Elsa.Common.Contracts;
 using Elsa.Common.Models;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Core.State;
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.HttpEndpoints/Activities/MapTo.cs b/src/samples/aspnet/Elsa.Samples.AspNet.HttpEndpoints/Activities/MapTo.cs
index 4b9255f2f..b063ffbc5 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.HttpEndpoints/Activities/MapTo.cs
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.HttpEndpoints/Activities/MapTo.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.AspNet.HttpEndpoints.Activities;
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Home/Index.cshtml b/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Home/Index.cshtml
index f67020193..3881a961d 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Home/Index.cshtml
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Home/Index.cshtml
@@ -1,4 +1,5 @@
-@model Elsa.Samples.AspNet.Onboarding.Web.Views.Home.IndexViewModel
+@using Microsoft.AspNetCore.Mvc.TagHelpers
+@model Elsa.Samples.AspNet.Onboarding.Web.Views.Home.IndexViewModel
 @{
     ViewData["Title"] = "Home Page";
 }
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Shared/_Layout.cshtml b/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Shared/_Layout.cshtml
index 64630617e..1a151c76f 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Shared/_Layout.cshtml
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.Onboarding.Web/Views/Shared/_Layout.cshtml
@@ -1,4 +1,5 @@
-<!DOCTYPE html>
+@using Microsoft.AspNetCore.Mvc.TagHelpers
+<!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="utf-8"/>
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Workflows/HungryWorkflow.cs b/src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Workflows/HungryWorkflow.cs
index b48db29ac..51e07f5e0 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Workflows/HungryWorkflow.cs
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Workflows/HungryWorkflow.cs
@@ -3,6 +3,7 @@ using Elsa.Http;
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Runtime.Activities;
 using Microsoft.AspNetCore.Http;
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
index eeaad66bf..4071486bb 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Extensions/WorkflowExecutionContextExtensions.cs
@@ -1,5 +1,6 @@
 using Elsa.Extensions;
 using Elsa.Samples.AspNet.WorkflowContexts.Providers;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.AspNet.WorkflowContexts.Extensions;
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/CustomerWorkflowContextProvider.cs b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/CustomerWorkflowContextProvider.cs
index df800699f..be16c9dba 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/CustomerWorkflowContextProvider.cs
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/CustomerWorkflowContextProvider.cs
@@ -2,6 +2,7 @@ using Elsa.Samples.AspNet.WorkflowContexts.Contracts;
 using Elsa.Samples.AspNet.WorkflowContexts.Entities;
 using Elsa.Samples.AspNet.WorkflowContexts.Extensions;
 using Elsa.WorkflowContexts.Abstractions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.AspNet.WorkflowContexts.Providers;
diff --git a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/OrderWorkflowContextProvider.cs b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/OrderWorkflowContextProvider.cs
index ea0fc9b54..1cc2656d5 100644
--- a/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/OrderWorkflowContextProvider.cs
+++ b/src/samples/aspnet/Elsa.Samples.AspNet.WorkflowContexts/Providers/OrderWorkflowContextProvider.cs
@@ -1,5 +1,6 @@
 using Elsa.Samples.AspNet.WorkflowContexts.Entities;
 using Elsa.WorkflowContexts.Abstractions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.AspNet.WorkflowContexts.Providers;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.Bookmarks/Activities/MyEvent.cs b/src/samples/console/Elsa.Samples.ConsoleApp.Bookmarks/Activities/MyEvent.cs
index ff1bb27b4..4c8d2f6d8 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.Bookmarks/Activities/MyEvent.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.Bookmarks/Activities/MyEvent.cs
@@ -1,3 +1,4 @@
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.ConsoleApp.Bookmarks.Activities;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskAge.cs b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskAge.cs
index dc9d4ea2f..fadc8f3b0 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskAge.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskAge.cs
@@ -1,5 +1,7 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 public class AskAge : Composite<int>
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskDetails.cs b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskDetails.cs
index 5a9136e09..4f25c2944 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskDetails.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskDetails.cs
@@ -1,5 +1,7 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 public class AskDetails : Composite<Person>
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskName.cs b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskName.cs
index 77b43af49..f4839c1bc 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskName.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Activities/AskName.cs
@@ -1,6 +1,8 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 public class AskName : Composite<string>
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Program.cs b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Program.cs
index 0a2cabf79..e27986de1 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Program.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.Composition/Program.cs
@@ -1,6 +1,7 @@
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.ConditionalWorkflows/Program.cs b/src/samples/console/Elsa.Samples.ConsoleApp.ConditionalWorkflows/Program.cs
index 9c266773e..bd0786d9a 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.ConditionalWorkflows/Program.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.ConditionalWorkflows/Program.cs
@@ -1,6 +1,7 @@
 using Elsa.Extensions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Activities/Sum.cs b/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Activities/Sum.cs
index 2a9462a42..a76a1b430 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Activities/Sum.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Activities/Sum.cs
@@ -1,4 +1,6 @@
 using Elsa.Extensions;
+using Elsa.Workflows.Core;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.ConsoleApp.CustomActivities.Activities;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Program.cs b/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Program.cs
index e7b4495c8..3fe5debbb 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Program.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.CustomActivities/Program.cs
@@ -2,6 +2,7 @@
 using Elsa.Samples.ConsoleApp.CustomActivities.Activities;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.FlowchartWorkflows/Program.cs b/src/samples/console/Elsa.Samples.ConsoleApp.FlowchartWorkflows/Program.cs
index 9718bc4cc..6c6c4e1de 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.FlowchartWorkflows/Program.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.FlowchartWorkflows/Program.cs
@@ -3,6 +3,7 @@ using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Activities.Flowchart.Activities;
 using Elsa.Workflows.Core.Activities.Flowchart.Models;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForEachWorkflow.cs b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForEachWorkflow.cs
index 0a5154844..a15e9747f 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForEachWorkflow.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForEachWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Scheduling.Activities;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.ConsoleApp.LoopingWorkflows.Workflows;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForWorkflow.cs b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForWorkflow.cs
index 2b0294ede..f28e7b289 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForWorkflow.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/ForWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Scheduling.Activities;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.ConsoleApp.LoopingWorkflows.Workflows;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/WhileWorkflow.cs b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/WhileWorkflow.cs
index f739454fa..d4926edb1 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/WhileWorkflow.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.LoopingWorkflows/Workflows/WhileWorkflow.cs
@@ -1,5 +1,6 @@
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.ConsoleApp.LoopingWorkflows.Workflows;
diff --git a/src/samples/console/Elsa.Samples.ConsoleApp.WorkflowFunctions/Workflows/AddWorkflow.cs b/src/samples/console/Elsa.Samples.ConsoleApp.WorkflowFunctions/Workflows/AddWorkflow.cs
index 02fa93153..5ae86045e 100644
--- a/src/samples/console/Elsa.Samples.ConsoleApp.WorkflowFunctions/Workflows/AddWorkflow.cs
+++ b/src/samples/console/Elsa.Samples.ConsoleApp.WorkflowFunctions/Workflows/AddWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Samples.WorkflowFunctions.Workflows;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForEachWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForEachWorkflow.cs
index 1db95654e..0185957d1 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForEachWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForEachWorkflow.cs
@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Activities;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForWorkflow.cs
index 5108e75f9..26823906f 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakForWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Activities;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileForkWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileForkWorkflow.cs
index ecc0ad554..5d94b1669 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileForkWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileForkWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Runtime.Activities;
 
diff --git a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileWorkflow.cs
index 99025b362..f3e13c6e0 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/Break/BreakWhileWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Activities;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/Finish/FinishTests.cs b/test/integration/Elsa.IntegrationTests/Activities/Finish/FinishTests.cs
index bd0db15ac..38e83e53a 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/Finish/FinishTests.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/Finish/FinishTests.cs
@@ -1,6 +1,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using Elsa.Testing.Shared;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/ForEach/ForEachWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/ForEach/ForEachWorkflow.cs
index 7796035ea..82b0d5a05 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/ForEach/ForEachWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/ForEach/ForEachWorkflow.cs
@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Activities;
diff --git a/test/integration/Elsa.IntegrationTests/Activities/ForEach/NestedForEachWithBreakWorkflow.cs b/test/integration/Elsa.IntegrationTests/Activities/ForEach/NestedForEachWithBreakWorkflow.cs
index aa5ea867d..c4b010a4d 100644
--- a/test/integration/Elsa.IntegrationTests/Activities/ForEach/NestedForEachWithBreakWorkflow.cs
+++ b/test/integration/Elsa.IntegrationTests/Activities/ForEach/NestedForEachWithBreakWorkflow.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Activities;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows.cs b/test/integration/Elsa.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows.cs
index 19cb60bb9..a83ac57eb 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Runtime.Activities;
 
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/Composites/Workflows.cs b/test/integration/Elsa.IntegrationTests/Scenarios/Composites/Workflows.cs
index f7f7d227d..9bfd3d64f 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/Composites/Workflows.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/Composites/Workflows.cs
@@ -1,8 +1,10 @@
 using Elsa.Extensions;
 using Elsa.JavaScript.Activities;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Scenarios.Composites;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/CompositesPassingData/Workflows.cs b/test/integration/Elsa.IntegrationTests/Scenarios/CompositesPassingData/Workflows.cs
index 9089c8918..d5c8f9562 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/CompositesPassingData/Workflows.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/CompositesPassingData/Workflows.cs
@@ -2,6 +2,7 @@ using Elsa.Extensions;
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Elsa.Workflows.Management.Activities.SetOutput;
 
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/FlowchartCompletion/Tests.cs b/test/integration/Elsa.IntegrationTests/Scenarios/FlowchartCompletion/Tests.cs
index 2cf1da42c..884350a45 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/FlowchartCompletion/Tests.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/FlowchartCompletion/Tests.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Threading.Tasks;
 using Elsa.Testing.Shared;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Models;
 using Xunit;
 using Xunit.Abstractions;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/BraidedWorkflowTests.cs b/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/BraidedWorkflowTests.cs
index 8df20997d..0f1d86d81 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/BraidedWorkflowTests.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/BraidedWorkflowTests.cs
@@ -2,6 +2,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using Elsa.IntegrationTests.Scenarios.ImplicitJoins.Workflows;
 using Elsa.Testing.Shared;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/ImplicitLoopWorkflowTests.cs b/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/ImplicitLoopWorkflowTests.cs
index a1c632e71..fc43d7e8c 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/ImplicitLoopWorkflowTests.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/ImplicitJoins/ImplicitLoopWorkflowTests.cs
@@ -2,6 +2,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using Elsa.IntegrationTests.Scenarios.ImplicitJoins.Workflows;
 using Elsa.Testing.Shared;
+using Elsa.Workflows.Core;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/SetGetVariables/Workflows.cs b/test/integration/Elsa.IntegrationTests/Scenarios/SetGetVariables/Workflows.cs
index 8231f850a..1248473cf 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/SetGetVariables/Workflows.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/SetGetVariables/Workflows.cs
@@ -1,6 +1,7 @@
 using Elsa.Workflows.Core.Abstractions;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Scenarios.SetGetVariables;
diff --git a/test/integration/Elsa.IntegrationTests/Scenarios/WorkflowResults/Tests.cs b/test/integration/Elsa.IntegrationTests/Scenarios/WorkflowResults/Tests.cs
index 7695280fc..6c632846e 100644
--- a/test/integration/Elsa.IntegrationTests/Scenarios/WorkflowResults/Tests.cs
+++ b/test/integration/Elsa.IntegrationTests/Scenarios/WorkflowResults/Tests.cs
@@ -2,6 +2,7 @@ using System.Threading.Tasks;
 using Elsa.Testing.Shared;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
diff --git a/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Models.cs b/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Models.cs
index 0e718c7d1..2d3a40b8e 100644
--- a/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Models.cs
+++ b/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Models.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.IntegrationTests.Serialization.VariableTypes;
diff --git a/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Tests.cs b/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Tests.cs
index 3b0b4ffa1..edfdda93e 100644
--- a/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Tests.cs
+++ b/test/integration/Elsa.IntegrationTests/Serialization/VariableTypes/Tests.cs
@@ -2,6 +2,7 @@ using System.Collections.ObjectModel;
 using System.Linq;
 using Elsa.Testing.Shared;
 using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Memory;
 using Elsa.Workflows.Core.Models;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;