diff --git a/docs/canon/workflow-runtime.md b/docs/canon/workflow-runtime.md
index 026145133..0583cec16 100644
--- a/docs/canon/workflow-runtime.md
+++ b/docs/canon/workflow-runtime.md
@@ -67,6 +67,7 @@ owner: eanzhao
    - 通过依赖推导（`IWorkflowModuleDependencyExpander`）确定所需模块，经 `WorkflowModuleFactory` 创建并安装
    - 收到 `ChatRequestEvent` envelope 后发布 `StartWorkflowEvent`
    - fork/resume-from-step seed 只走 request-level `WorkflowChatRequestEvent.fork_seed -> StartWorkflowEvent.fork_seed`；run bind 只表达 definition/run binding，不携带 seed。
+   - run lineage 是 `WorkflowRunGAgent` owned committed fact，不从 route、actor id、graph/topology、workflow name 或 ID 前缀推断。`WorkflowRunLineage` 分离 retry/fork 与 `workflow_call` parent/child 关系，并始终使用可路由 public `runId`；actor address 只作为可选寻址信息保留。legacy 或未携带 lineage 的 run 必须显式返回 unavailable/legacy-unavailable。
    - 由 `WorkflowExecutionKernel` 推进 `StepRequestEvent -> StepCompletedEvent -> WorkflowCompletedEvent`
 
 ```
diff --git a/src/workflow/Aevatar.Workflow.Abstractions/workflow_execution_messages.proto b/src/workflow/Aevatar.Workflow.Abstractions/workflow_execution_messages.proto
index 73c7b9791..a31a5549c 100644
--- a/src/workflow/Aevatar.Workflow.Abstractions/workflow_execution_messages.proto
+++ b/src/workflow/Aevatar.Workflow.Abstractions/workflow_execution_messages.proto
@@ -270,6 +270,7 @@ message WorkflowRunForkSeed
   map<string, string> variables = 3;
   int32 attempt = 4;
   WorkflowStepIdempotencyState start_step_idempotency = 5;
+  string original_run_id = 6;
 }
 
 message WorkflowStepIdempotencyState
@@ -280,6 +281,60 @@ message WorkflowStepIdempotencyState
   string idempotency_key = 4;
 }
 
+enum WorkflowRunLineageAvailability
+{
+  WORKFLOW_RUN_LINEAGE_AVAILABILITY_UNSPECIFIED = 0;
+  WORKFLOW_RUN_LINEAGE_AVAILABILITY_AVAILABLE = 1;
+  WORKFLOW_RUN_LINEAGE_AVAILABILITY_UNAVAILABLE = 2;
+  WORKFLOW_RUN_LINEAGE_AVAILABILITY_LEGACY_UNAVAILABLE = 3;
+}
+
+enum WorkflowRunLineageRelationKind
+{
+  WORKFLOW_RUN_LINEAGE_RELATION_KIND_UNSPECIFIED = 0;
+  WORKFLOW_RUN_LINEAGE_RELATION_KIND_RETRY_FORK = 1;
+  WORKFLOW_RUN_LINEAGE_RELATION_KIND_SUB_WORKFLOW = 2;
+}
+
+message WorkflowRunLineageRunRef
+{
+  string run_id = 1;
+  string actor_id = 2;
+  string relationship_id = 3;
+  string step_id = 4;
+  int32 attempt = 5;
+  WorkflowRunLineageRelationKind relation_kind = 6;
+}
+
+message WorkflowRunRetryForkLineage
+{
+  WorkflowRunLineageAvailability availability = 1;
+  string source_run_id = 2;
+  string original_run_id = 3;
+  int32 attempt = 4;
+  string start_at_step_id = 5;
+  repeated WorkflowRunLineageRunRef child_runs = 6;
+}
+
+message WorkflowRunSubWorkflowLineage
+{
+  WorkflowRunLineageAvailability availability = 1;
+  string parent_run_id = 2;
+  string parent_actor_id = 3;
+  string parent_step_id = 4;
+  string root_run_id = 5;
+  int32 depth = 6;
+  repeated WorkflowRunLineageRunRef child_runs = 7;
+}
+
+message WorkflowRunLineage
+{
+  WorkflowRunLineageAvailability availability = 1;
+  WorkflowRunRetryForkLineage retry_fork = 2;
+  WorkflowRunSubWorkflowLineage sub_workflow = 3;
+  string unavailable_reason = 4;
+}
+
 message WorkflowRunForkRequestedEvent
 {
   string source_run_id = 1;
@@ -288,6 +343,17 @@ message WorkflowRunForkRequestedEvent
   string scope_id = 4;
 }
 
+message WorkflowRunLineageRecordedEvent
+{
+  string source_run_id = 1;
+  string child_run_id = 2;
+  string child_actor_id = 3;
+  string start_at_step_id = 4;
+  int32 attempt = 5;
+  WorkflowRunLineageRelationKind relation_kind = 6;
+  string original_run_id = 7;
+}
+
 message StartWorkflowEvent
 {
   string workflow_name = 1;
@@ -324,6 +390,7 @@ message BindWorkflowRunDefinitionEvent
   string revision_id = 12;
   // Authoritative committed definition version/watermark used by this run. Zero means unavailable.
   int64 definition_version = 13;
+  WorkflowRunLineage initial_lineage = 14;
 }
 
 // Idempotent provisioning command for a stable Run actor identity. The first
@@ -380,6 +447,7 @@ message WorkflowRunExecutionStartedEvent
   string workflow_command_id = 11;
   string workflow_correlation_id = 12;
   string current_turn_id = 13;
+  WorkflowRunLineage lineage = 14;
 }
 message WorkflowRunExecutionContextDelta
 {
diff --git a/src/workflow/Aevatar.Workflow.Application.Abstractions/Observatory/IWorkflowRunObservatoryQueryService.cs b/src/workflow/Aevatar.Workflow.Application.Abstractions/Observatory/IWorkflowRunObservatoryQueryService.cs
index e27fc69e0..301a31332 100644
--- a/src/workflow/Aevatar.Workflow.Application.Abstractions/Observatory/IWorkflowRunObservatoryQueryService.cs
+++ b/src/workflow/Aevatar.Workflow.Application.Abstractions/Observatory/IWorkflowRunObservatoryQueryService.cs
@@ -1,3 +1,4 @@
+using Aevatar.Workflow.Abstractions;
 using Aevatar.Workflow.Application.Abstractions.Queries;
 
 namespace Aevatar.Workflow.Application.Abstractions.Observatory;
@@ -122,6 +123,8 @@ public sealed class WorkflowActivityRunFeedRow
     public long StateVersion { get; init; }
 
     public WorkflowRunRecoveryCapability RecoveryCapability { get; init; } = new();
+
+    public WorkflowRunLineage Lineage { get; init; } = new();
 }
 
 public sealed class WorkflowActivityRunInitiatorSummary
@@ -196,6 +199,8 @@ public sealed class ObservatoryRunSummary
     // 06-23-observatory-run-coverage-filter: canonical run origin/type (draft | member-invoke | ...),
     // empty for legacy/unstamped runs. Drives the run-type filter + badge.
     public string RunOrigin { get; init; } = string.Empty;
+
+    public WorkflowRunLineage Lineage { get; init; } = new();
 }
 
 public sealed class ObservatoryRunDetail
@@ -227,6 +232,8 @@ public sealed class ObservatoryRunDetail
     public ObservatoryUsageTotals UsageTotals { get; init; } = new();
 
     public WorkflowRunRecoveryCapability RecoveryCapability { get; init; } = new();
+
+    public WorkflowRunLineage Lineage { get; init; } = new();
 }
 
 public sealed class ObservatoryRunDiagnostic
diff --git a/src/workflow/Aevatar.Workflow.Application.Abstractions/Queries/workflow_projection_query_models.proto b/src/workflow/Aevatar.Workflow.Application.Abstractions/Queries/workflow_projection_query_models.proto
index a0363c1fb..73fa2280d 100644
--- a/src/workflow/Aevatar.Workflow.Application.Abstractions/Queries/workflow_projection_query_models.proto
+++ b/src/workflow/Aevatar.Workflow.Application.Abstractions/Queries/workflow_projection_query_models.proto
@@ -89,6 +89,7 @@ message WorkflowActorSnapshot {
   WorkflowRunActivityWaitingSnapshot activity_waiting = 31;
   string run_id = 32;
   WorkflowRunRecoveryCapability recovery_capability = 33;
+  aevatar.workflow.WorkflowRunLineage lineage = 34;
 }
 
 message WorkflowRunActivityInitiatorSnapshot {
diff --git a/src/workflow/Aevatar.Workflow.Application.Abstractions/RunForks/WorkflowForkRunModels.cs b/src/workflow/Aevatar.Workflow.Application.Abstractions/RunForks/WorkflowForkRunModels.cs
index 89ee3a0e3..17bbabbf5 100644
--- a/src/workflow/Aevatar.Workflow.Application.Abstractions/RunForks/WorkflowForkRunModels.cs
+++ b/src/workflow/Aevatar.Workflow.Application.Abstractions/RunForks/WorkflowForkRunModels.cs
@@ -122,4 +122,5 @@ public sealed record WorkflowForkRunAcceptedReceipt(
     string CommandId,
     string CorrelationId,
     DateTimeOffset AckedAt,
-    string NewRunId = "");
+    string NewRunId = "",
+    string OriginalRunId = "");
diff --git a/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowChatRunModels.cs b/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowChatRunModels.cs
index d2262ec35..0cad2b9c7 100644
--- a/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowChatRunModels.cs
+++ b/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowChatRunModels.cs
@@ -147,7 +147,8 @@ public sealed record WorkflowChatRunForkSeed(
     string StartAtStepId,
     IReadOnlyDictionary<string, string> Variables,
     int Attempt = 0,
-    WorkflowStepIdempotencyView? StartStepIdempotency = null);
+    WorkflowStepIdempotencyView? StartStepIdempotency = null,
+    string OriginalRunId = "");
 
 public enum WorkflowChatSourceKind
 {
diff --git a/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowRunPorts.cs b/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowRunPorts.cs
index 9e7ba0c4d..357c07efe 100644
--- a/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowRunPorts.cs
+++ b/src/workflow/Aevatar.Workflow.Application.Abstractions/Runs/WorkflowRunPorts.cs
@@ -165,7 +165,8 @@ public sealed record WorkflowRunForkSeedView(
     IReadOnlyDictionary<string, WorkflowStepIdempotencyView>? IdempotencyByStepId = null,
     WorkflowCapabilityAdmissionPlan? CapabilityAdmissionPlan = null,
     string RevisionId = "",
-    long DefinitionVersion = 0)
+    long DefinitionVersion = 0,
+    string OriginalRunId = "")
 {
     public WorkflowRunForkSeedView()
         : this(
@@ -182,7 +183,8 @@ public WorkflowRunForkSeedView()
             new Dictionary<string, WorkflowStepIdempotencyView>(StringComparer.Ordinal),
             null,
             string.Empty,
-            0)
+            0,
+            string.Empty)
     {
     }
 }
diff --git a/src/workflow/Aevatar.Workflow.Application/Observatory/WorkflowRunObservatoryQueryService.cs b/src/workflow/Aevatar.Workflow.Application/Observatory/WorkflowRunObservatoryQueryService.cs
index 658ce77fe..5e9debaa9 100644
--- a/src/workflow/Aevatar.Workflow.Application/Observatory/WorkflowRunObservatoryQueryService.cs
+++ b/src/workflow/Aevatar.Workflow.Application/Observatory/WorkflowRunObservatoryQueryService.cs
@@ -231,6 +231,7 @@ private async Task<ObservatoryRunDetail> BuildRunDetailAsync(
                 Diagnostics = BuildDiagnostics(snapshot, report: null, steps: [], viewEvents: []),
                 UsageTotals = new ObservatoryUsageTotals(),
                 RecoveryCapability = CloneRecoveryCapability(snapshot),
+                Lineage = CloneLineage(snapshot),
             };
         }
 
@@ -266,6 +267,7 @@ private async Task<ObservatoryRunDetail> BuildRunDetailAsync(
             Statistics = ToStatistics(report.Summary),
             UsageTotals = WorkflowRunObservatoryTimelineMapper.ToUsageTotals(report.Usage),
             RecoveryCapability = CloneRecoveryCapability(snapshot),
+            Lineage = CloneLineage(snapshot),
         };
     }
 
@@ -378,6 +380,7 @@ private static ObservatoryRunSummary ToRunSummary(WorkflowActorSnapshot snapshot
             StateVersion = snapshot.StateVersion,
             ScopeId = snapshot.ScopeId,
             RunOrigin = snapshot.RunOrigin,
+            Lineage = CloneLineage(snapshot),
         };
     }
 
@@ -408,12 +411,28 @@ private static WorkflowActivityRunFeedRow ToActivityRunFeedRow(WorkflowActorSnap
             DurationMs = completedAtUtc == null || !snapshot.HasDurationMs ? null : snapshot.DurationMs,
             StateVersion = snapshot.StateVersion,
             RecoveryCapability = CloneRecoveryCapability(snapshot),
+            Lineage = CloneLineage(snapshot),
         };
     }
 
     private static WorkflowRunRecoveryCapability CloneRecoveryCapability(WorkflowActorSnapshot snapshot) =>
         snapshot.RecoveryCapability?.Clone() ?? new WorkflowRunRecoveryCapability();
 
+    private static Aevatar.Workflow.Abstractions.WorkflowRunLineage CloneLineage(WorkflowActorSnapshot snapshot) =>
+        snapshot.Lineage?.Clone() ?? new Aevatar.Workflow.Abstractions.WorkflowRunLineage
+        {
+            Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            UnavailableReason = "Run lineage is unavailable for this legacy run.",
+            RetryFork = new Aevatar.Workflow.Abstractions.WorkflowRunRetryForkLineage
+            {
+                Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            },
+            SubWorkflow = new Aevatar.Workflow.Abstractions.WorkflowRunSubWorkflowLineage
+            {
+                Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            },
+        };
+
     private static WorkflowActivityRunInitiatorSummary ToActivityInitiatorSummary(
         WorkflowRunActivityInitiatorSnapshot? source) =>
         source == null
diff --git a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunAcceptedReceiptFactory.cs b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunAcceptedReceiptFactory.cs
index 79632d2f9..8644c7284 100644
--- a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunAcceptedReceiptFactory.cs
+++ b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunAcceptedReceiptFactory.cs
@@ -21,6 +21,7 @@ public WorkflowForkRunAcceptedReceipt Create(
             context.CommandId,
             context.CorrelationId,
             DateTimeOffset.UtcNow,
-            target.RunId);
+            target.RunId,
+            target.OriginalRunId);
     }
 }
diff --git a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTarget.cs b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTarget.cs
index 8990e0b57..db0974c31 100644
--- a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTarget.cs
+++ b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTarget.cs
@@ -10,6 +10,7 @@ internal sealed class WorkflowForkRunCommandTarget : ICommandDispatchTarget, ICo
 
     public WorkflowForkRunCommandTarget(
         string sourceRunId,
+        string originalRunId,
         string startAtStepId,
         string actorId,
         string runId,
@@ -19,6 +20,7 @@ public WorkflowForkRunCommandTarget(
         IWorkflowRunProvisioningPort runProvisioningPort)
     {
         SourceRunId = Normalize(sourceRunId);
+        OriginalRunId = Normalize(originalRunId);
         StartAtStepId = Normalize(startAtStepId);
         RunId = Normalize(runId);
         PreparedRequest = preparedRequest ?? throw new ArgumentNullException(nameof(preparedRequest));
@@ -31,6 +33,8 @@ public WorkflowForkRunCommandTarget(
 
     public string SourceRunId { get; }
 
+    public string OriginalRunId { get; }
+
     public string StartAtStepId { get; }
 
     public string RunId { get; }
diff --git a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTargetResolver.cs b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTargetResolver.cs
index 69bb734c5..6b89be7ce 100644
--- a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTargetResolver.cs
+++ b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowForkRunCommandTargetResolver.cs
@@ -105,6 +105,7 @@ public async Task<CommandTargetResolution<WorkflowForkRunCommandTarget, Workflow
         var source = WorkflowChatSource.DefinitionActor(creationReceipt.ActorId, validation.WorkflowName);
         var target = new WorkflowForkRunCommandTarget(
             sourceRunId,
+            ResolveOriginalRunId(seedView, sourceRunId),
             startAtStepId,
             creationReceipt.ActorId,
             creationReceipt.RunId,
@@ -196,7 +197,8 @@ private static WorkflowChatRunRequest BuildChatRunRequest(
                 startAtStepId,
                 variables,
                 Math.Max(0, command.Attempt),
-                ResolveStartStepIdempotency(seedView, startAtStepId)),
+                ResolveStartStepIdempotency(seedView, startAtStepId),
+                ResolveOriginalRunId(seedView, sourceRunId)),
             TargetSeed: new WorkflowRunTargetSeed(
                 actorId,
                 workflowName,
@@ -272,6 +274,14 @@ private static string ResolveResumeInput(
             : null;
     }
 
+    private static string ResolveOriginalRunId(
+        WorkflowRunForkSeedView seedView,
+        string sourceRunId)
+    {
+        var originalRunId = Normalize(seedView.OriginalRunId);
+        return string.IsNullOrWhiteSpace(originalRunId) ? sourceRunId : originalRunId;
+    }
+
     private static bool IsTerminal(string status) =>
         !string.IsNullOrWhiteSpace(status) && TerminalStatuses.Contains(status.Trim());
 
diff --git a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowRunForkCoordinator.cs b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowRunForkCoordinator.cs
index ccf4ffa77..7b7535330 100644
--- a/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowRunForkCoordinator.cs
+++ b/src/workflow/Aevatar.Workflow.Application/RunForks/WorkflowRunForkCoordinator.cs
@@ -1,7 +1,9 @@
 using Aevatar.CQRS.Core.Abstractions.Commands;
+using Aevatar.Foundation.Abstractions;
 using Aevatar.Foundation.Abstractions.EventSourcing;
 using Aevatar.Workflow.Abstractions;
 using Aevatar.Workflow.Application.Abstractions.RunForks;
+using Google.Protobuf.WellKnownTypes;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 
@@ -10,13 +12,16 @@ namespace Aevatar.Workflow.Application.RunForks;
 internal sealed class WorkflowRunForkCoordinator : ICommittedStatePublicationHook
 {
     private readonly Lazy<ICommandDispatchService<WorkflowForkRunCommand, WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>> _forkDispatchService;
+    private readonly IActorDispatchPort? _dispatchPort;
     private readonly ILogger<WorkflowRunForkCoordinator> _logger;
 
     public WorkflowRunForkCoordinator(
         Lazy<ICommandDispatchService<WorkflowForkRunCommand, WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>> forkDispatchService,
+        IActorDispatchPort? dispatchPort = null,
         ILogger<WorkflowRunForkCoordinator>? logger = null)
     {
         _forkDispatchService = forkDispatchService ?? throw new ArgumentNullException(nameof(forkDispatchService));
+        _dispatchPort = dispatchPort;
         _logger = logger ?? NullLogger<WorkflowRunForkCoordinator>.Instance;
     }
 
@@ -25,7 +30,8 @@ internal WorkflowRunForkCoordinator(
         ILogger<WorkflowRunForkCoordinator>? logger = null)
         : this(new Lazy<ICommandDispatchService<WorkflowForkRunCommand, WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>>(
             () => forkDispatchService ?? throw new ArgumentNullException(nameof(forkDispatchService))),
-            logger)
+            dispatchPort: null,
+            logger: logger)
     {
     }
 
@@ -68,7 +74,11 @@ public async Task BeforePublishAsync(CommittedStatePublicationContext context, C
                     requested.Attempt,
                     result.Error?.Code,
                     result.Error?.Reason);
+                return;
             }
+
+            await RecordAcceptedForkLineageAsync(context, requested, result.Receipt, ct)
+                .ConfigureAwait(false);
         }
         catch (Exception ex)
         {
@@ -80,4 +90,48 @@ public async Task BeforePublishAsync(CommittedStatePublicationContext context, C
                 requested.Attempt);
         }
     }
+
+    private async Task RecordAcceptedForkLineageAsync(
+        CommittedStatePublicationContext context,
+        WorkflowRunForkRequestedEvent requested,
+        WorkflowForkRunAcceptedReceipt? receipt,
+        CancellationToken ct)
+    {
+        if (_dispatchPort == null || receipt == null || !receipt.Accepted)
+            return;
+
+        var sourceActorId = context.ActorId?.Trim() ?? string.Empty;
+        var childRunId = receipt.NewRunId?.Trim() ?? string.Empty;
+        if (string.IsNullOrWhiteSpace(sourceActorId) || string.IsNullOrWhiteSpace(childRunId))
+            return;
+
+        // Implement (issue #3252):
+        //   Behavior: source runs record accepted fork children with routable runId and separate child actor address.
+        //   Why this shape: the coordinator only relays the accepted child identity back to the source actor; the source actor commits the lineage fact.
+        await _dispatchPort.DispatchAsync(
+            sourceActorId,
+            new EventEnvelope
+            {
+                Id = Guid.NewGuid().ToString("N"),
+                Timestamp = Timestamp.FromDateTimeOffset(DateTimeOffset.UtcNow),
+                Payload = Any.Pack(new WorkflowRunLineageRecordedEvent
+                {
+                    SourceRunId = requested.SourceRunId ?? string.Empty,
+                    ChildRunId = childRunId,
+                    ChildActorId = receipt.NewRunActorId ?? string.Empty,
+                    StartAtStepId = requested.StartAtStepId ?? string.Empty,
+                    Attempt = Math.Max(0, requested.Attempt),
+                    RelationKind = WorkflowRunLineageRelationKind.RetryFork,
+                    OriginalRunId = string.IsNullOrWhiteSpace(receipt.OriginalRunId)
+                        ? requested.SourceRunId ?? string.Empty
+                        : receipt.OriginalRunId,
+                }),
+                Route = EnvelopeRouteSemantics.CreateTopologyPublication(sourceActorId, TopologyAudience.Self),
+                Propagation = new EnvelopePropagation
+                {
+                    CorrelationId = Guid.NewGuid().ToString("N"),
+                },
+            },
+            ct).ConfigureAwait(false);
+    }
 }
diff --git a/src/workflow/Aevatar.Workflow.Application/Runs/WorkflowChatRequestEnvelopeFactory.cs b/src/workflow/Aevatar.Workflow.Application/Runs/WorkflowChatRequestEnvelopeFactory.cs
index 608767c6b..c56a54b44 100644
--- a/src/workflow/Aevatar.Workflow.Application/Runs/WorkflowChatRequestEnvelopeFactory.cs
+++ b/src/workflow/Aevatar.Workflow.Application/Runs/WorkflowChatRequestEnvelopeFactory.cs
@@ -192,6 +192,7 @@ private static Aevatar.Workflow.Abstractions.WorkflowRunForkSeed ToProto(
             SourceRunId = Normalize(source.SourceRunId),
             StartAtStepId = Normalize(source.StartAtStepId),
             Attempt = Math.Max(0, source.Attempt),
+            OriginalRunId = Normalize(source.OriginalRunId),
         };
         if (source.StartStepIdempotency != null)
         {
diff --git a/src/workflow/Aevatar.Workflow.Core/Primitives/SubWorkflowOrchestrator.cs b/src/workflow/Aevatar.Workflow.Core/Primitives/SubWorkflowOrchestrator.cs
index e32c1770f..57e5ba28e 100644
--- a/src/workflow/Aevatar.Workflow.Core/Primitives/SubWorkflowOrchestrator.cs
+++ b/src/workflow/Aevatar.Workflow.Core/Primitives/SubWorkflowOrchestrator.cs
@@ -743,6 +743,21 @@ public static WorkflowRunState ApplySubWorkflowInvocationRegistered(WorkflowRunS
         RemovePendingDefinitionResolution(next, invocationId);
         RemovePendingInvocation(next, invocationId, childRunId);
         AddPendingInvocation(next, pending);
+        // Implement (issue #3252):
+        //   Behavior: parent workflow runs expose durable sub-workflow child run identities separately from retry/fork lineage.
+        //   Why this shape: the committed invocation registration is the parent-owned fact; graph/topology edges remain execution-path data.
+        next.Lineage = WorkflowRunGAgent.EnsureLineage(next.Lineage);
+        next.Lineage.Availability = WorkflowRunLineageAvailability.Available;
+        next.Lineage.SubWorkflow ??= new WorkflowRunSubWorkflowLineage();
+        next.Lineage.SubWorkflow.Availability = WorkflowRunLineageAvailability.Available;
+        WorkflowRunGAgent.UpsertLineageChild(
+            next.Lineage.SubWorkflow.ChildRuns,
+            childRunId,
+            pending.ChildActorId,
+            invocationId,
+            pending.ParentStepId,
+            attempt: 0,
+            WorkflowRunLineageRelationKind.SubWorkflow);
         return next;
     }
 
@@ -919,7 +934,7 @@ await AdvancePendingSubWorkflowInvocationHandoffAsync(
 
         if (pending.HandoffPhase < SubWorkflowInvocationHandoffPhase.Bound)
         {
-            await BindSubWorkflowActorAsync(childActor.Id, definition, pending.ChildRunId, state, ct);
+            await BindSubWorkflowActorAsync(childActor.Id, definition, pending, state, ct);
             if (persistBinding)
             {
                 await PersistBindingUpsertedAsync(
@@ -1085,13 +1100,13 @@ private static SubWorkflowInvocationHandoffPhase ToSubWorkflowInvocationHandoffP
     private Task BindSubWorkflowActorAsync(
         string actorId,
         WorkflowDefinitionSnapshot definition,
-        string runId,
+        WorkflowRunState.Types.PendingSubWorkflowInvocation pending,
         WorkflowRunState state,
         CancellationToken ct)
     {
         return _dispatchPort.DispatchAsync(
             actorId,
-            CreateWorkflowRunBindEnvelope(definition, runId, state),
+            CreateWorkflowRunBindEnvelope(definition, pending, state),
             ct);
     }
 
@@ -1466,7 +1481,7 @@ private async Task<IActor> ResolveOrCreateWorkflowActorByIdAsync(string actorId)
 
     private EventEnvelope CreateWorkflowRunBindEnvelope(
         WorkflowDefinitionSnapshot definition,
-        string runId,
+        WorkflowRunState.Types.PendingSubWorkflowInvocation pending,
         WorkflowRunState state)
     {
         var inlineWorkflowYamls = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
@@ -1486,7 +1501,7 @@ private EventEnvelope CreateWorkflowRunBindEnvelope(
             DefinitionActorId = definition.DefinitionActorId ?? string.Empty,
             WorkflowYaml = definition.WorkflowYaml ?? string.Empty,
             WorkflowName = definition.WorkflowName ?? string.Empty,
-            RunId = runId ?? string.Empty,
+            RunId = pending.ChildRunId ?? string.Empty,
             ScopeId = string.IsNullOrWhiteSpace(definition.ScopeId)
                 ? state.ScopeId ?? string.Empty
                 : definition.ScopeId,
@@ -1494,6 +1509,10 @@ private EventEnvelope CreateWorkflowRunBindEnvelope(
             RevisionId = definition.RevisionId ?? string.Empty,
             DefinitionVersion = Math.Max(0, definition.DefinitionVersion),
             ExpectedExecutionMode = state.ExpectedExecutionMode,
+            // Implement (issue #3252):
+            //   Behavior: child workflow runs expose their parent/root run lineage as typed bind facts.
+            //   Why this shape: the child actor commits lineage from the call-site handoff instead of deriving it from runtime topology.
+            InitialLineage = BuildChildInitialLineage(pending, _ownerActorIdAccessor()),
         };
 
         return new EventEnvelope
@@ -1509,6 +1528,30 @@ private EventEnvelope CreateWorkflowRunBindEnvelope(
         };
     }
 
+    private static WorkflowRunLineage BuildChildInitialLineage(
+        WorkflowRunState.Types.PendingSubWorkflowInvocation pending,
+        string parentActorId)
+    {
+        var parentRunId = WorkflowRunIdNormalizer.Normalize(pending.ParentRunId);
+        return new WorkflowRunLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Available,
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+            SubWorkflow = new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                ParentRunId = parentRunId,
+                ParentActorId = parentActorId?.Trim() ?? string.Empty,
+                ParentStepId = pending.ParentStepId?.Trim() ?? string.Empty,
+                RootRunId = NormalizeRootRunId(pending.RootRunId, parentRunId),
+                Depth = Math.Max(0, pending.Depth),
+            },
+        };
+    }
+
     private static bool ShouldEvictBinding(
         WorkflowRunState state,
         WorkflowRunState.Types.SubWorkflowBinding binding,
diff --git a/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.IdentityProvisioning.cs b/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.IdentityProvisioning.cs
index c986024be..14d7e2607 100644
--- a/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.IdentityProvisioning.cs
+++ b/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.IdentityProvisioning.cs
@@ -30,7 +30,8 @@ await BindWorkflowRunDefinitionAsync(
                 binding.RevisionId,
                 binding.DefinitionVersion,
                 binding.CapabilityAdmissionPlan,
-                binding.ExpectedExecutionMode);
+                binding.ExpectedExecutionMode,
+                binding.InitialLineage);
         }
         else
         {
diff --git a/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.cs b/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.cs
index f5f070a6d..c018d5735 100644
--- a/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.cs
+++ b/src/workflow/Aevatar.Workflow.Core/WorkflowRunGAgent.cs
@@ -13,6 +13,7 @@
 using Aevatar.Workflow.Core.Modules;
 using Aevatar.Workflow.Core.Primitives;
 using Google.Protobuf;
+using Google.Protobuf.Collections;
 using Google.Protobuf.WellKnownTypes;
 using Microsoft.Extensions.Logging;
 using System.Diagnostics.CodeAnalysis;
@@ -426,6 +427,7 @@ public async Task BindWorkflowRunDefinitionAsync(
         long definitionVersion,
         WorkflowCapabilityAdmissionPlan? capabilityAdmissionPlan,
         ExternalCapabilityExecutionMode expectedExecutionMode,
+        WorkflowRunLineage? initialLineage = null,
         CancellationToken ct = default)
     {
         if (expectedExecutionMode == ExternalCapabilityExecutionMode.Unspecified ||
@@ -459,6 +461,13 @@ public async Task BindWorkflowRunDefinitionAsync(
             CapabilityAdmissionPlan = capabilityAdmissionPlan?.Clone(),
             ExpectedExecutionMode = expectedExecutionMode,
         };
+        if (initialLineage != null)
+        {
+            // Fix (review round 1, F1):
+            //   Sub-workflow child lineage was stamped before dispatch but dropped before bind commit.
+            //   Preserve InitialLineage in the authoritative bind event and cover the bind handler path.
+            bindDefinitionEvent.InitialLineage = initialLineage.Clone();
+        }
         if (inlineWorkflowYamls != null)
         {
             foreach (var (key, value) in inlineWorkflowYamls)
@@ -487,7 +496,8 @@ public Task HandleBindWorkflowRunDefinition(BindWorkflowRunDefinitionEvent reque
             request.RevisionId,
             request.DefinitionVersion,
             request.CapabilityAdmissionPlan,
-            request.ExpectedExecutionMode);
+            request.ExpectedExecutionMode,
+            request.InitialLineage);
 
     public override Task<string> GetDescriptionAsync()
     {
@@ -657,6 +667,7 @@ await HandleWorkflowCompleted(new WorkflowCompletedEvent
             CurrentTurnId = string.IsNullOrWhiteSpace(request.CurrentTurnId)
                 ? request.ConversationContext?.CurrentTurnId ?? string.Empty
                 : request.CurrentTurnId,
+            Lineage = BuildExecutionStartLineage(request.ForkSeed, State.Lineage, runId),
         };
         if (request.CompletionNotificationTarget != null)
             executionStarted.CompletionNotificationTarget = request.CompletionNotificationTarget.Clone();
@@ -2035,6 +2046,7 @@ protected override WorkflowRunState TransitionState(WorkflowRunState current, IM
             .On<WorkflowRunExecutionContextClearedEvent>(ApplyWorkflowRunExecutionContextCleared)
             .On<WorkflowExecutionStateUpsertedEvent>(ApplyWorkflowExecutionStateUpserted)
             .On<WorkflowExecutionStateClearedEvent>(ApplyWorkflowExecutionStateCleared)
+            .On<WorkflowRunLineageRecordedEvent>(ApplyWorkflowRunLineageRecorded)
             .On<CompensableStepDispatchedEvent>(ApplyCompensableStepDispatched)
             .On<StepCompletedEvent>(ApplyStepCompleted)
             .On<CompensationRequestEvent>(ApplyCompensationRequest)
@@ -2226,6 +2238,7 @@ private WorkflowRunState ApplyBindWorkflowRunDefinition(WorkflowRunState current
         next.TerminalNotificationAttempt = 0;
         next.TerminalNotificationDeliveryStatus = WorkflowRunTerminalNotificationDeliveryStatus.Unspecified;
         next.TerminalNotificationRetryCallbackId = string.Empty;
+        next.Lineage = evt.InitialLineage?.Clone() ?? CreateUnavailableLineage("Run lineage is unavailable for this run.");
         next.InlineWorkflowYamls.Clear();
         foreach (var (workflowNameKey, workflowYamlValue) in evt.InlineWorkflowYamls)
         {
@@ -2312,6 +2325,7 @@ private static WorkflowRunState ApplyWorkflowRunExecutionStarted(WorkflowRunStat
         next.TerminalNotificationDeliveryStatus = WorkflowRunTerminalNotificationDeliveryStatus.Unspecified;
         next.TerminalNotificationRetryCallbackId = string.Empty;
         next.CurrentTurnId = evt.CurrentTurnId?.Trim() ?? string.Empty;
+        next.Lineage = evt.Lineage?.Clone() ?? current.Lineage?.Clone() ?? CreateUnavailableLineage("Run lineage is unavailable for this run.");
         next.InteractiveActionHandoffs.Clear();
         next.ExecutionContext ??= new WorkflowRunExecutionContextState();
         ApplyExecutionContextDelta(next.ExecutionContext, evt.ExecutionContextDelta);
@@ -2325,6 +2339,198 @@ private static WorkflowRunState ApplyWorkflowRunExecutionStarted(WorkflowRunStat
         return next;
     }
 
+    [EventHandler]
+    public async Task HandleWorkflowRunLineageRecorded(WorkflowRunLineageRecordedEvent evt)
+    {
+        ArgumentNullException.ThrowIfNull(evt);
+
+        var sourceRunId = WorkflowRunIdNormalizer.Normalize(evt.SourceRunId);
+        var currentRunId = WorkflowRunIdNormalizer.Normalize(RunId);
+        if (string.IsNullOrWhiteSpace(sourceRunId) ||
+            string.IsNullOrWhiteSpace(currentRunId) ||
+            !string.Equals(sourceRunId, currentRunId, StringComparison.Ordinal))
+        {
+            Logger.LogWarning(
+                "Reject workflow lineage record for mismatched source run. actor={ActorId} currentRun={CurrentRunId} sourceRun={SourceRunId}",
+                Id,
+                currentRunId,
+                sourceRunId);
+            return;
+        }
+
+        if (evt.RelationKind != WorkflowRunLineageRelationKind.RetryFork ||
+            string.IsNullOrWhiteSpace(evt.ChildRunId))
+        {
+            Logger.LogWarning(
+                "Reject workflow lineage record with unsupported or missing relation. sourceRun={SourceRunId} childRun={ChildRunId} relation={RelationKind}",
+                sourceRunId,
+                evt.ChildRunId,
+                evt.RelationKind);
+            return;
+        }
+
+        // Implement (issue #3252):
+        //   Behavior: source/original runs expose retried or forked child run identities from committed facts.
+        //   Why this shape: the source actor records its own lineage instead of queries deriving children from actor IDs or graph topology.
+        await PersistDomainEventAsync(new WorkflowRunLineageRecordedEvent
+        {
+            SourceRunId = sourceRunId,
+            ChildRunId = WorkflowRunIdNormalizer.Normalize(evt.ChildRunId),
+            ChildActorId = evt.ChildActorId?.Trim() ?? string.Empty,
+            StartAtStepId = evt.StartAtStepId?.Trim() ?? string.Empty,
+            Attempt = Math.Max(0, evt.Attempt),
+            RelationKind = WorkflowRunLineageRelationKind.RetryFork,
+            OriginalRunId = WorkflowRunIdNormalizer.Normalize(evt.OriginalRunId),
+        });
+    }
+
+    private static WorkflowRunState ApplyWorkflowRunLineageRecorded(
+        WorkflowRunState current,
+        WorkflowRunLineageRecordedEvent evt)
+    {
+        if (evt.RelationKind != WorkflowRunLineageRelationKind.RetryFork)
+            return current;
+
+        var childRunId = WorkflowRunIdNormalizer.Normalize(evt.ChildRunId);
+        if (string.IsNullOrWhiteSpace(childRunId))
+            return current;
+
+        var next = current.Clone();
+        next.Lineage = EnsureLineage(next.Lineage);
+        next.Lineage.Availability = WorkflowRunLineageAvailability.Available;
+        next.Lineage.RetryFork ??= new WorkflowRunRetryForkLineage();
+        next.Lineage.RetryFork.Availability = WorkflowRunLineageAvailability.Available;
+        if (string.IsNullOrWhiteSpace(next.Lineage.RetryFork.SourceRunId))
+            next.Lineage.RetryFork.SourceRunId = WorkflowRunIdNormalizer.Normalize(evt.SourceRunId);
+        if (string.IsNullOrWhiteSpace(next.Lineage.RetryFork.OriginalRunId))
+        {
+            var originalRunId = WorkflowRunIdNormalizer.Normalize(evt.OriginalRunId);
+            next.Lineage.RetryFork.OriginalRunId = string.IsNullOrWhiteSpace(originalRunId)
+                ? next.Lineage.RetryFork.SourceRunId
+                : originalRunId;
+        }
+
+        UpsertLineageChild(
+            next.Lineage.RetryFork.ChildRuns,
+            childRunId,
+            evt.ChildActorId,
+            relationshipId: string.Empty,
+            stepId: evt.StartAtStepId,
+            Math.Max(0, evt.Attempt),
+            WorkflowRunLineageRelationKind.RetryFork);
+        return next;
+    }
+
+    internal static WorkflowRunLineage BuildExecutionStartLineage(
+        WorkflowRunForkSeed? forkSeed,
+        WorkflowRunLineage? currentLineage,
+        string runId)
+    {
+        if (forkSeed == null || string.IsNullOrWhiteSpace(forkSeed.SourceRunId))
+            return currentLineage?.Clone() ?? CreateUnavailableLineage("Run lineage is unavailable for this run.");
+
+        var sourceRunId = WorkflowRunIdNormalizer.Normalize(forkSeed.SourceRunId);
+        var originalRunId = WorkflowRunIdNormalizer.Normalize(forkSeed.OriginalRunId);
+        if (string.IsNullOrWhiteSpace(originalRunId))
+            originalRunId = sourceRunId;
+
+        // Implement (issue #3252):
+        //   Behavior: retried and forked child runs carry source and original run IDs as typed lineage.
+        //   Why this shape: fork lineage is stamped from the accepted fork seed instead of inferred from routes or run ID strings.
+        return new WorkflowRunLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Available,
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                SourceRunId = sourceRunId,
+                OriginalRunId = originalRunId,
+                Attempt = Math.Max(0, forkSeed.Attempt),
+                StartAtStepId = forkSeed.StartAtStepId?.Trim() ?? string.Empty,
+            },
+            SubWorkflow = currentLineage?.SubWorkflow?.Clone() ?? new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+        };
+    }
+
+    internal static WorkflowRunLineage CreateUnavailableLineage(string reason) =>
+        new()
+        {
+            Availability = WorkflowRunLineageAvailability.Unavailable,
+            UnavailableReason = string.IsNullOrWhiteSpace(reason)
+                ? "Run lineage is unavailable for this run."
+                : reason,
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+            SubWorkflow = new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+        };
+
+    internal static WorkflowRunLineage EnsureLineage(WorkflowRunLineage? lineage)
+    {
+        var next = lineage?.Clone() ?? CreateUnavailableLineage("Run lineage is unavailable for this run.");
+        next.RetryFork ??= new WorkflowRunRetryForkLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Unavailable,
+        };
+        next.SubWorkflow ??= new WorkflowRunSubWorkflowLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Unavailable,
+        };
+        return next;
+    }
+
+    internal static void UpsertLineageChild(
+        RepeatedField<WorkflowRunLineageRunRef> childRuns,
+        string runId,
+        string? actorId,
+        string relationshipId,
+        string? stepId,
+        int attempt,
+        WorkflowRunLineageRelationKind relationKind)
+    {
+        var normalizedRunId = WorkflowRunIdNormalizer.Normalize(runId);
+        if (string.IsNullOrWhiteSpace(normalizedRunId))
+            return;
+
+        var normalizedActorId = actorId?.Trim() ?? string.Empty;
+        for (var i = 0; i < childRuns.Count; i++)
+        {
+            if (!string.Equals(childRuns[i].RunId, normalizedRunId, StringComparison.Ordinal) ||
+                childRuns[i].RelationKind != relationKind)
+            {
+                continue;
+            }
+
+            childRuns[i] = new WorkflowRunLineageRunRef
+            {
+                RunId = normalizedRunId,
+                ActorId = string.IsNullOrWhiteSpace(normalizedActorId) ? childRuns[i].ActorId ?? string.Empty : normalizedActorId,
+                RelationshipId = string.IsNullOrWhiteSpace(relationshipId) ? childRuns[i].RelationshipId : relationshipId,
+                StepId = string.IsNullOrWhiteSpace(stepId) ? childRuns[i].StepId : stepId.Trim(),
+                Attempt = Math.Max(0, attempt),
+                RelationKind = relationKind,
+            };
+            return;
+        }
+
+        childRuns.Add(new WorkflowRunLineageRunRef
+        {
+            RunId = normalizedRunId,
+            ActorId = normalizedActorId,
+            RelationshipId = relationshipId ?? string.Empty,
+            StepId = stepId?.Trim() ?? string.Empty,
+            Attempt = Math.Max(0, attempt),
+            RelationKind = relationKind,
+        });
+    }
+
     private static WorkflowRunState ApplyWorkflowRunExecutionContextUpdated(
         WorkflowRunState current,
         WorkflowRunExecutionContextUpdatedEvent evt)
diff --git a/src/workflow/Aevatar.Workflow.Core/workflow_state.proto b/src/workflow/Aevatar.Workflow.Core/workflow_state.proto
index a81dd5767..b58b7a4ab 100644
--- a/src/workflow/Aevatar.Workflow.Core/workflow_state.proto
+++ b/src/workflow/Aevatar.Workflow.Core/workflow_state.proto
@@ -202,6 +202,7 @@ message WorkflowRunState
   string revision_id = 52;
   int64 definition_version = 53;
   aevatar.workflow.WorkflowRecoveryFailureKind terminal_recovery_failure_kind = 54;
+  aevatar.workflow.WorkflowRunLineage lineage = 55;
 }
 
 message WorkflowRunInitiatorState
diff --git a/src/workflow/Aevatar.Workflow.Projection/Projectors/WorkflowExecutionCurrentStateProjector.cs b/src/workflow/Aevatar.Workflow.Projection/Projectors/WorkflowExecutionCurrentStateProjector.cs
index f096420ec..3d6a2ca8a 100644
--- a/src/workflow/Aevatar.Workflow.Projection/Projectors/WorkflowExecutionCurrentStateProjector.cs
+++ b/src/workflow/Aevatar.Workflow.Projection/Projectors/WorkflowExecutionCurrentStateProjector.cs
@@ -99,6 +99,7 @@ public WorkflowExecutionCurrentStateProjector(
             ForkSeedCompletedStepIds = seedSnapshot.CompletedStepIds.ToList(),
             ForkSeedLastFailedStepId = seedSnapshot.LastFailedStepId,
             RecoveryCapability = BuildRecoveryCapability(state, seedSnapshot),
+            Lineage = MapLineage(state.Lineage),
             ForkSeedIdempotencies = seedSnapshot.IdempotencyByStepId.ToDictionary(
                 x => x.Key,
                 x => MapStepIdempotency(x.Value),
@@ -151,6 +152,21 @@ private static WorkflowRunActivityInitiatorReadModel MapInitiator(WorkflowRunIni
         };
     }
 
+    private static WorkflowRunLineage MapLineage(WorkflowRunLineage? lineage) =>
+        lineage?.Clone() ?? new WorkflowRunLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Unavailable,
+            UnavailableReason = "Run lineage is unavailable for this run.",
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+            SubWorkflow = new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+        };
+
     private static WorkflowRunActivityStepReadModel ResolveCurrentStep(WorkflowRunState state)
     {
         foreach (var executionState in state.ExecutionStates.Values)
diff --git a/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowExecutionReadModelMapper.cs b/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowExecutionReadModelMapper.cs
index e457125e7..439287497 100644
--- a/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowExecutionReadModelMapper.cs
+++ b/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowExecutionReadModelMapper.cs
@@ -41,6 +41,7 @@ public WorkflowActorSnapshot ToActorSnapshot(WorkflowExecutionCurrentStateDocume
             ActivityFirstFailure = MapActivityFirstFailure(source.ActivityFirstFailure),
             ActivityWaiting = MapActivityWaiting(source.ActivityWaiting),
             RecoveryCapability = MapRecoveryCapability(source.RecoveryCapability),
+            Lineage = MapLineage(source.Lineage),
         };
         if (source.HasDurationMs)
             snapshot.DurationMs = source.DurationMs;
@@ -62,6 +63,22 @@ private static WorkflowRunRecoveryCapability MapRecoveryCapability(
         };
     }
 
+    private static Aevatar.Workflow.Abstractions.WorkflowRunLineage MapLineage(
+        Aevatar.Workflow.Abstractions.WorkflowRunLineage? source) =>
+        source?.Clone() ?? new Aevatar.Workflow.Abstractions.WorkflowRunLineage
+        {
+            Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            UnavailableReason = "Run lineage is unavailable for this legacy run.",
+            RetryFork = new Aevatar.Workflow.Abstractions.WorkflowRunRetryForkLineage
+            {
+                Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            },
+            SubWorkflow = new Aevatar.Workflow.Abstractions.WorkflowRunSubWorkflowLineage
+            {
+                Availability = Aevatar.Workflow.Abstractions.WorkflowRunLineageAvailability.LegacyUnavailable,
+            },
+        };
+
     private static WorkflowRecoveryActionCapability MapRecoveryActionCapability(
         WorkflowRecoveryActionCapabilityReadModel? source)
     {
diff --git a/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowRunForkSeedReadModelMapper.cs b/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowRunForkSeedReadModelMapper.cs
index eac817345..a9de37a99 100644
--- a/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowRunForkSeedReadModelMapper.cs
+++ b/src/workflow/Aevatar.Workflow.Projection/ReadModels/WorkflowRunForkSeedReadModelMapper.cs
@@ -34,7 +34,8 @@ public WorkflowRunForkSeedView ToSeedView(WorkflowExecutionCurrentStateDocument
                 StringComparer.Ordinal),
             source.CapabilityAdmissionPlan?.Clone(),
             source.RevisionId ?? string.Empty,
-            source.DefinitionVersion);
+            source.DefinitionVersion,
+            ResolveOriginalRunId(source.Lineage, source.RunId));
     }
 
     public WorkflowRunForkSeedProjectionSnapshot ToProjectionSnapshot(WorkflowRunState state)
@@ -106,6 +107,17 @@ private static WorkflowStepIdempotencyView ToView(WorkflowStepIdempotencyReadMod
             source.StepId ?? string.Empty,
             source.LogicalAttempt,
             source.IdempotencyKey ?? string.Empty);
+
+    private static string ResolveOriginalRunId(
+        Aevatar.Workflow.Abstractions.WorkflowRunLineage? lineage,
+        string? runId)
+    {
+        var originalRunId = lineage?.RetryFork?.OriginalRunId?.Trim() ?? string.Empty;
+        if (!string.IsNullOrWhiteSpace(originalRunId))
+            return originalRunId;
+
+        return runId?.Trim() ?? string.Empty;
+    }
 }
 
 public sealed record WorkflowRunForkSeedProjectionSnapshot(
diff --git a/src/workflow/Aevatar.Workflow.Projection/workflow_projection_transport.proto b/src/workflow/Aevatar.Workflow.Projection/workflow_projection_transport.proto
index 85194081b..c41a6009f 100644
--- a/src/workflow/Aevatar.Workflow.Projection/workflow_projection_transport.proto
+++ b/src/workflow/Aevatar.Workflow.Projection/workflow_projection_transport.proto
@@ -133,6 +133,7 @@ message WorkflowExecutionCurrentStateDocument {
   WorkflowRunRecoveryCapabilityReadModel recovery_capability = 44;
   string revision_id = 45;
   int64 definition_version = 46;
+  aevatar.workflow.WorkflowRunLineage lineage = 47;
 }
 
 message WorkflowRunActivityInitiatorReadModel {
diff --git a/test/Aevatar.GAgents.ChannelRuntime.Tests/ChannelWorkflowResultDeliveryContractTests.cs b/test/Aevatar.GAgents.ChannelRuntime.Tests/ChannelWorkflowResultDeliveryContractTests.cs
index 9daeb2c84..1246fedeb 100644
--- a/test/Aevatar.GAgents.ChannelRuntime.Tests/ChannelWorkflowResultDeliveryContractTests.cs
+++ b/test/Aevatar.GAgents.ChannelRuntime.Tests/ChannelWorkflowResultDeliveryContractTests.cs
@@ -600,6 +600,8 @@ await Agent.BindWorkflowRunDefinitionAsync(
                 runOrigin: null,
                 scheduleId: null,
                 workflowId: null,
+                revisionId: null,
+                definitionVersion: 0,
                 capabilityAdmissionPlan: null,
                 expectedExecutionMode: command.ExpectedExecutionMode,
                 ct: ct);
diff --git a/test/Aevatar.Integration.Tests/TestDoubles/WorkflowGAgentTestBase.cs b/test/Aevatar.Integration.Tests/TestDoubles/WorkflowGAgentTestBase.cs
index 25ea79cb1..eec1a26bd 100644
--- a/test/Aevatar.Integration.Tests/TestDoubles/WorkflowGAgentTestBase.cs
+++ b/test/Aevatar.Integration.Tests/TestDoubles/WorkflowGAgentTestBase.cs
@@ -102,9 +102,11 @@ internal static Task BindInteractiveWorkflowRunDefinitionAsync(
                 runOrigin,
                 scheduleId,
                 workflowId: null,
+                revisionId: null,
+                definitionVersion: 0,
                 capabilityAdmissionPlan,
                 ExternalCapabilityExecutionMode.Interactive,
-                ct);
+                ct: ct);
 
         internal static async Task<WorkflowGAgent> CreateRegisteredDefinitionAgentAsync(
             RecordingActorRuntime runtime,
diff --git a/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkCoordinatorTests.cs b/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkCoordinatorTests.cs
index 5642c7d42..af7193d27 100644
--- a/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkCoordinatorTests.cs
+++ b/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkCoordinatorTests.cs
@@ -49,10 +49,54 @@ public async Task BeforePublishAsync_WhenCommittedForkRequestedEvent_ShouldDispa
         command.ScopeId.Should().Be("scope-1");
     }
 
-    private static CommittedStatePublicationContext CreateContext(IMessage evt) =>
+    [Fact]
+    public async Task BeforePublishAsync_WhenForkAccepted_ShouldDispatchLineageRecordToSourceActor()
+    {
+        var forkDispatchService = new RecordingForkDispatchService
+        {
+            Receipt = new WorkflowForkRunAcceptedReceipt(
+                "run-source-gamma",
+                "actor-child-delta",
+                "wf",
+                true,
+                "cmd",
+                "corr",
+                DateTimeOffset.UtcNow,
+                "run-child-beta",
+                "run-original-alpha"),
+        };
+        var dispatchPort = new RecordingActorDispatchPort();
+        var coordinator = new WorkflowRunForkCoordinator(
+            new Lazy<ICommandDispatchService<WorkflowForkRunCommand, WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>>(
+                () => forkDispatchService),
+            dispatchPort);
+
+        await coordinator.BeforePublishAsync(
+            CreateContext(new WorkflowRunForkRequestedEvent
+            {
+                SourceRunId = "run-source-gamma",
+                StartAtStepId = "step-retry",
+                Attempt = 4,
+                ScopeId = "scope-alpha",
+            }, actorId: "actor-source-epsilon"),
+            CancellationToken.None);
+
+        var dispatched = dispatchPort.Dispatched.Should().ContainSingle().Subject;
+        dispatched.ActorId.Should().Be("actor-source-epsilon");
+        var recorded = dispatched.Envelope.Payload.Unpack<WorkflowRunLineageRecordedEvent>();
+        recorded.SourceRunId.Should().Be("run-source-gamma");
+        recorded.ChildRunId.Should().Be("run-child-beta");
+        recorded.ChildActorId.Should().Be("actor-child-delta");
+        recorded.OriginalRunId.Should().Be("run-original-alpha");
+        recorded.StartAtStepId.Should().Be("step-retry");
+        recorded.Attempt.Should().Be(4);
+        recorded.RelationKind.Should().Be(WorkflowRunLineageRelationKind.RetryFork);
+    }
+
+    private static CommittedStatePublicationContext CreateContext(IMessage evt, string actorId = "run-source") =>
         new()
         {
-            ActorId = "run-source",
+            ActorId = actorId,
             ActorType = typeof(object),
             Published = new CommittedStateEventPublished
             {
@@ -73,6 +117,8 @@ private sealed class RecordingForkDispatchService
     {
         public List<WorkflowForkRunCommand> Commands { get; } = [];
 
+        public WorkflowForkRunAcceptedReceipt? Receipt { get; init; }
+
         public Task<CommandDispatchResult<WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>> DispatchAsync(
             WorkflowForkRunCommand command,
             CancellationToken ct = default)
@@ -80,7 +126,7 @@ public Task<CommandDispatchResult<WorkflowForkRunAcceptedReceipt, WorkflowForkRu
             ct.ThrowIfCancellationRequested();
             Commands.Add(command);
             return Task.FromResult(CommandDispatchResult<WorkflowForkRunAcceptedReceipt, WorkflowForkRunStartError>.Success(
-                new WorkflowForkRunAcceptedReceipt(
+                Receipt ?? new WorkflowForkRunAcceptedReceipt(
                     command.SourceRunId,
                     "new-run",
                     "wf",
@@ -90,4 +136,18 @@ public Task<CommandDispatchResult<WorkflowForkRunAcceptedReceipt, WorkflowForkRu
                     DateTimeOffset.UtcNow)));
         }
     }
+
+    private sealed class RecordingActorDispatchPort : IActorDispatchPort
+    {
+        public List<RecordedDispatch> Dispatched { get; } = [];
+
+        public Task<DispatchAdmission> DispatchAsync(string actorId, EventEnvelope envelope, CancellationToken ct = default)
+        {
+            ct.ThrowIfCancellationRequested();
+            Dispatched.Add(new RecordedDispatch(actorId, envelope));
+            return Task.FromResult(DispatchAdmissionFactory.Create(actorId, envelope));
+        }
+    }
+
+    private sealed record RecordedDispatch(string ActorId, EventEnvelope Envelope);
 }
diff --git a/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkSeedQueryPortTests.cs b/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkSeedQueryPortTests.cs
index d3c390a50..526ccc1d6 100644
--- a/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkSeedQueryPortTests.cs
+++ b/test/Aevatar.Workflow.Application.Tests/WorkflowRunForkSeedQueryPortTests.cs
@@ -60,6 +60,32 @@ public void ForkSeedReadModelMapper_ShouldMapCompletedRunForkSeed()
         view.IdempotencyByStepId!["step-b"].IdempotencyKey.Should().Be("run-completed:step-b:1");
     }
 
+    [Fact]
+    public void ForkSeedReadModelMapper_ShouldCarryOriginalRunIdFromLineage()
+    {
+        var mapper = new WorkflowRunForkSeedReadModelMapper();
+
+        var view = mapper.ToSeedView(new WorkflowExecutionCurrentStateDocument
+        {
+            RunId = "run-source-gamma",
+            Status = "failed",
+            ScopeId = "scope-alpha",
+            Lineage = new WorkflowRunLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                RetryFork = new WorkflowRunRetryForkLineage
+                {
+                    Availability = WorkflowRunLineageAvailability.Available,
+                    SourceRunId = "run-source-gamma",
+                    OriginalRunId = "run-original-alpha",
+                },
+            },
+        });
+
+        view.SourceRunId.Should().Be("run-source-gamma");
+        view.OriginalRunId.Should().Be("run-original-alpha");
+    }
+
     [Fact]
     public async Task GetForkSeedAsync_ShouldReadFailedRunForkSeedThroughCurrentStateReadModel()
     {
diff --git a/test/Aevatar.Workflow.Application.Tests/WorkflowRunObservatoryQueryServiceTests.cs b/test/Aevatar.Workflow.Application.Tests/WorkflowRunObservatoryQueryServiceTests.cs
index e9291ccc4..373e33e3e 100644
--- a/test/Aevatar.Workflow.Application.Tests/WorkflowRunObservatoryQueryServiceTests.cs
+++ b/test/Aevatar.Workflow.Application.Tests/WorkflowRunObservatoryQueryServiceTests.cs
@@ -146,6 +146,22 @@ public async Task ListActivityRunsForScopeAsync_ShouldReturnPagedTypedRows_FromC
             Availability = "available",
         };
         snapshot.RecoveryCapability = RecoveryCapability();
+        snapshot.Lineage = new WorkflowRunLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Available,
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                SourceRunId = "run-source-gamma",
+                OriginalRunId = "run-original-alpha",
+                Attempt = 2,
+                StartAtStepId = "step-failed",
+            },
+            SubWorkflow = new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+        };
         var currentState = new FakeCurrentStateQueryPort
         {
             PageResult = new WorkflowActorCurrentStatePage([snapshot], "cursor-next", 42),
@@ -195,6 +211,10 @@ public async Task ListActivityRunsForScopeAsync_ShouldReturnPagedTypedRows_FromC
         row.RecoveryCapability.WorkflowDefinitionRevisionId.Should().Be("rev-recovery");
         row.RecoveryCapability.RetryFailedStep.Eligibility.Should().Be(WorkflowRecoveryEligibility.Eligible);
         row.RecoveryCapability.RetryFailedStep.StartingStepId.Should().Be("step-failed");
+        row.Lineage.RetryFork.SourceRunId.Should().Be("run-source-gamma");
+        row.Lineage.RetryFork.OriginalRunId.Should().Be("run-original-alpha");
+        row.Lineage.RetryFork.StartAtStepId.Should().Be("step-failed");
+        row.Lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
     }
 
     [Fact]
@@ -225,6 +245,7 @@ public async Task ListActivityRunsForScopeAsync_ShouldRepresentMissingFactsExpli
         row.Waiting.Availability.Should().Be("unavailable");
         row.CompletedAtUtc.Should().BeNull();
         row.DurationMs.Should().BeNull();
+        row.Lineage.Availability.Should().Be(WorkflowRunLineageAvailability.LegacyUnavailable);
     }
 
     [Fact]
diff --git a/test/Aevatar.Workflow.Core.Tests/Execution/WorkflowExecutionContextAdapterTests.cs b/test/Aevatar.Workflow.Core.Tests/Execution/WorkflowExecutionContextAdapterTests.cs
index bb96ee88c..d534e94e9 100644
--- a/test/Aevatar.Workflow.Core.Tests/Execution/WorkflowExecutionContextAdapterTests.cs
+++ b/test/Aevatar.Workflow.Core.Tests/Execution/WorkflowExecutionContextAdapterTests.cs
@@ -94,6 +94,8 @@ await agent.BindWorkflowRunDefinitionAsync(
             runOrigin: null,
             scheduleId: null,
             workflowId: null,
+            revisionId: null,
+            definitionVersion: 0,
             capabilityAdmissionPlan: null,
             expectedExecutionMode: ExternalCapabilityExecutionMode.Interactive);
         var adapter = WorkflowExecutionContextAdapter.Create(new RecordingEventHandlerContext(), stateHost);
diff --git a/test/Aevatar.Workflow.Core.Tests/Primitives/SubWorkflowOrchestratorTests.cs b/test/Aevatar.Workflow.Core.Tests/Primitives/SubWorkflowOrchestratorTests.cs
index 73872240d..8375defce 100644
--- a/test/Aevatar.Workflow.Core.Tests/Primitives/SubWorkflowOrchestratorTests.cs
+++ b/test/Aevatar.Workflow.Core.Tests/Primitives/SubWorkflowOrchestratorTests.cs
@@ -1313,6 +1313,40 @@ public void ApplyStateTransitions_ShouldMaintainBindingAndInvocationIndexes()
         state.PendingChildRunIdsByParentRunId["parent-run"].ChildRunIds.Should().ContainSingle(x => x == "child-run-b");
     }
 
+    [Fact]
+    public void ApplySubWorkflowInvocationRegistered_ShouldAppendTypedSubWorkflowChildLineage()
+    {
+        var state = SubWorkflowOrchestrator.ApplySubWorkflowInvocationRegistered(
+            new WorkflowRunState
+            {
+                RunId = "run-parent-alpha",
+            },
+            new SubWorkflowInvocationRegisteredEvent
+            {
+                InvocationId = "invoke-sub-001",
+                ParentRunId = "run-parent-alpha",
+                ParentStepId = "step-call-child",
+                WorkflowName = "sub_flow",
+                ChildActorId = "actor-child-delta",
+                ChildRunId = "run-child-beta",
+                Lifecycle = WorkflowCallLifecycle.Transient,
+                DefinitionActorId = "workflow-definition:sub_flow",
+                DefinitionVersion = 2,
+                RootRunId = "run-root-omega",
+                Depth = 1,
+            });
+
+        state.Lineage.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        state.Lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        state.Lineage.RetryFork.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+        var child = state.Lineage.SubWorkflow.ChildRuns.Should().ContainSingle().Subject;
+        child.RunId.Should().Be("run-child-beta");
+        child.ActorId.Should().Be("actor-child-delta");
+        child.RelationshipId.Should().Be("invoke-sub-001");
+        child.StepId.Should().Be("step-call-child");
+        child.RelationKind.Should().Be(WorkflowRunLineageRelationKind.SubWorkflow);
+    }
+
     [Fact]
     public void PruneIdleSubWorkflowBindings_ShouldKeepReferencedAndPendingSingletons()
     {
diff --git a/test/Aevatar.Workflow.Core.Tests/WorkflowRunGAgentForkOnFailureTests.cs b/test/Aevatar.Workflow.Core.Tests/WorkflowRunGAgentForkOnFailureTests.cs
index e3cdc8f28..adc3b293a 100644
--- a/test/Aevatar.Workflow.Core.Tests/WorkflowRunGAgentForkOnFailureTests.cs
+++ b/test/Aevatar.Workflow.Core.Tests/WorkflowRunGAgentForkOnFailureTests.cs
@@ -21,6 +21,100 @@ namespace Aevatar.Workflow.Core.Tests;
 
 public sealed class WorkflowRunGAgentForkOnFailureTests
 {
+    [Fact]
+    public void BuildExecutionStartLineage_WithForkSeed_ShouldExposeSourceAndOriginalRunIds()
+    {
+        var lineage = WorkflowRunGAgent.BuildExecutionStartLineage(
+            new WorkflowRunForkSeed
+            {
+                SourceRunId = "run-source-gamma",
+                OriginalRunId = "run-original-alpha",
+                StartAtStepId = "step-retry",
+                Attempt = 3,
+            },
+            currentLineage: null,
+            runId: "run-child-beta");
+
+        lineage.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        lineage.RetryFork.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        lineage.RetryFork.SourceRunId.Should().Be("run-source-gamma");
+        lineage.RetryFork.OriginalRunId.Should().Be("run-original-alpha");
+        lineage.RetryFork.StartAtStepId.Should().Be("step-retry");
+        lineage.RetryFork.Attempt.Should().Be(3);
+        lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+    }
+
+    [Fact]
+    public void BuildExecutionStartLineage_WithoutForkSeed_ShouldReturnExplicitUnavailableLineage()
+    {
+        var lineage = WorkflowRunGAgent.BuildExecutionStartLineage(
+            forkSeed: null,
+            currentLineage: null,
+            runId: "run-standalone-beta");
+
+        lineage.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+        lineage.RetryFork.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+        lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+        lineage.UnavailableReason.Should().Contain("unavailable");
+    }
+
+    [Fact]
+    public async Task HandleBindWorkflowRunDefinition_WithInitialSubWorkflowLineage_ShouldCommitAndApplyChildLineage()
+    {
+        const string childRunId = "run-child-beta";
+        const string parentRunId = "run-parent-alpha";
+        const string rootRunId = "run-root-omega";
+        var harness = await CreateUnboundRunAsync(childRunId);
+
+        var initialLineage = new WorkflowRunLineage
+        {
+            Availability = WorkflowRunLineageAvailability.Available,
+            RetryFork = new WorkflowRunRetryForkLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Unavailable,
+            },
+            SubWorkflow = new WorkflowRunSubWorkflowLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                ParentRunId = parentRunId,
+                ParentActorId = "actor-parent-gamma",
+                ParentStepId = "step-call-child",
+                RootRunId = rootRunId,
+                Depth = 2,
+            },
+        };
+
+        await harness.Agent.HandleBindWorkflowRunDefinition(new BindWorkflowRunDefinitionEvent
+        {
+            DefinitionActorId = "definition-child-delta",
+            WorkflowName = "wf_child_beta",
+            WorkflowYaml = WorkflowYaml(onFailure: false),
+            RunId = childRunId,
+            ScopeId = "scope-child",
+            ExpectedExecutionMode = ExternalCapabilityExecutionMode.Interactive,
+            InitialLineage = initialLineage,
+        });
+
+        var committed = CommittedEvents<BindWorkflowRunDefinitionEvent>(harness.CommittedPublisher)
+            .Should()
+            .ContainSingle()
+            .Subject;
+        committed.RunId.Should().Be(childRunId);
+        committed.InitialLineage.SubWorkflow.ParentRunId.Should().Be(parentRunId);
+        committed.InitialLineage.SubWorkflow.RootRunId.Should().Be(rootRunId);
+        committed.InitialLineage.SubWorkflow.ParentStepId.Should().Be("step-call-child");
+
+        harness.Agent.State.RunId.Should().Be(childRunId);
+        harness.Agent.State.Lineage.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        harness.Agent.State.Lineage.RetryFork.Availability.Should().Be(WorkflowRunLineageAvailability.Unavailable);
+        harness.Agent.State.Lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        harness.Agent.State.Lineage.SubWorkflow.ParentRunId.Should().Be(parentRunId);
+        harness.Agent.State.Lineage.SubWorkflow.ParentActorId.Should().Be("actor-parent-gamma");
+        harness.Agent.State.Lineage.SubWorkflow.ParentStepId.Should().Be("step-call-child");
+        harness.Agent.State.Lineage.SubWorkflow.RootRunId.Should().Be(rootRunId);
+        harness.Agent.State.Lineage.SubWorkflow.Depth.Should().Be(2);
+    }
+
     [Fact]
     public async Task TerminalFailedRun_WithForkPolicy_ShouldCommitForkRequestedEvent()
     {
@@ -386,6 +480,28 @@ private static async Task<RunHarness> CreateStartedRunAsync(string workflowYaml,
         return harness with { StepExecutionId = stepRequest.ExecutionId };
     }
 
+    private static async Task<RunHarness> CreateUnboundRunAsync(string runId)
+    {
+        var eventStore = new RecordingEventStore();
+        var committedHook = new RecordingCommittedStatePublicationHook();
+        var topologyPublisher = new RecordingEventPublisher(runId);
+        var agent = new WorkflowRunGAgent(
+            new UnsupportedActorRuntime(),
+            new UnsupportedActorRuntime(),
+            new EmptyEventModuleFactory(),
+            [new EmptyWorkflowModulePack()])
+        {
+            EventSourcingBehaviorFactory = new DefaultEventSourcingBehaviorFactory<WorkflowRunState>(eventStore),
+            EventPublisher = topologyPublisher,
+            Services = new TestServiceProvider(new NoopRuntimeCallbackScheduler(), committedHook),
+            Logger = NullLogger.Instance,
+        };
+        SetAgentId(agent, runId);
+        topologyPublisher.Agent = agent;
+        await agent.ActivateAsync();
+        return new RunHarness(agent, runId, string.Empty, committedHook, topologyPublisher);
+    }
+
     private static async Task<RunHarness> CreateRunAsync(
         string runId,
         string workflowYaml,
diff --git a/test/Aevatar.Workflow.Host.Api.Tests/WorkflowExecutionQueryPortsCoverageTests.cs b/test/Aevatar.Workflow.Host.Api.Tests/WorkflowExecutionQueryPortsCoverageTests.cs
index 046817e07..3a705ff5c 100644
--- a/test/Aevatar.Workflow.Host.Api.Tests/WorkflowExecutionQueryPortsCoverageTests.cs
+++ b/test/Aevatar.Workflow.Host.Api.Tests/WorkflowExecutionQueryPortsCoverageTests.cs
@@ -48,6 +48,72 @@ public void WorkflowExecutionReadModelMapper_ShouldMapCurrentStateStatuses(
         snapshot.DeadLetterRemainingUncompensated.Should().Be(2); snapshot.DeadLetterError.Should().Be("refund failed");
     }
 
+    [Fact]
+    public void WorkflowExecutionReadModelMapper_ShouldExposeTypedLineage()
+    {
+        var mapper = new WorkflowExecutionReadModelMapper();
+
+        var snapshot = mapper.ToActorSnapshot(new WorkflowExecutionCurrentStateDocument
+        {
+            RootActorId = "actor-child-delta",
+            RunId = "run-child-beta",
+            Status = "running",
+            Lineage = new WorkflowRunLineage
+            {
+                Availability = WorkflowRunLineageAvailability.Available,
+                RetryFork = new WorkflowRunRetryForkLineage
+                {
+                    Availability = WorkflowRunLineageAvailability.Available,
+                    SourceRunId = "run-source-gamma",
+                    OriginalRunId = "run-original-alpha",
+                    Attempt = 2,
+                    StartAtStepId = "step-retry",
+                },
+                SubWorkflow = new WorkflowRunSubWorkflowLineage
+                {
+                    Availability = WorkflowRunLineageAvailability.Available,
+                    ParentRunId = "run-parent-alpha",
+                    ParentActorId = "actor-parent-gamma",
+                    ParentStepId = "step-call-child",
+                    RootRunId = "run-root-omega",
+                    Depth = 2,
+                },
+            },
+        });
+
+        snapshot.RunId.Should().Be("run-child-beta");
+        snapshot.ActorId.Should().Be("actor-child-delta");
+        snapshot.Lineage.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        snapshot.Lineage.RetryFork.SourceRunId.Should().Be("run-source-gamma");
+        snapshot.Lineage.RetryFork.OriginalRunId.Should().Be("run-original-alpha");
+        snapshot.Lineage.RetryFork.StartAtStepId.Should().Be("step-retry");
+        snapshot.Lineage.RetryFork.Attempt.Should().Be(2);
+        snapshot.Lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.Available);
+        snapshot.Lineage.SubWorkflow.ParentRunId.Should().Be("run-parent-alpha");
+        snapshot.Lineage.SubWorkflow.ParentActorId.Should().Be("actor-parent-gamma");
+        snapshot.Lineage.SubWorkflow.ParentStepId.Should().Be("step-call-child");
+        snapshot.Lineage.SubWorkflow.RootRunId.Should().Be("run-root-omega");
+        snapshot.Lineage.SubWorkflow.Depth.Should().Be(2);
+    }
+
+    [Fact]
+    public void WorkflowExecutionReadModelMapper_WhenLineageMissing_ShouldReturnLegacyUnavailable()
+    {
+        var mapper = new WorkflowExecutionReadModelMapper();
+
+        var snapshot = mapper.ToActorSnapshot(new WorkflowExecutionCurrentStateDocument
+        {
+            RootActorId = "actor-legacy-delta",
+            RunId = "run-legacy-beta",
+            Status = "completed",
+        });
+
+        snapshot.Lineage.Availability.Should().Be(WorkflowRunLineageAvailability.LegacyUnavailable);
+        snapshot.Lineage.RetryFork.Availability.Should().Be(WorkflowRunLineageAvailability.LegacyUnavailable);
+        snapshot.Lineage.SubWorkflow.Availability.Should().Be(WorkflowRunLineageAvailability.LegacyUnavailable);
+        snapshot.Lineage.UnavailableReason.Should().Contain("legacy");
+    }
+
     [Fact]
     public void WorkflowExecutionReadModelMapper_ShouldExposeCurrentStateInputFileDescriptors()
     {