diff --git a/FORK.md b/FORK.md
index 23a0c6bb147..49fc922ee21 100644
--- a/FORK.md
+++ b/FORK.md
@@ -59,6 +59,11 @@ This repository is a fork of `pingdotgg/t3code`. Keep this file focused on fork
 
 - The fork adds thread goal support, goal activity rendering, and goal sidebar/panel UI.
 
+### Subagent Activity
+
+- Parent timelines keep subagent commands, file changes, tool calls, web searches, image views, and diffs.
+- Subagent messages, reasoning, goals, plans, token usage, and thread/turn state stay out of the parent timeline. Codex child relationships are recognized from both `collabAgentToolCall` and `subAgentActivity` items.
+
 ### Provider Launch Environment
 
 - Provider sessions use a shared launch environment pipeline instead of ad hoc environment assembly.
diff --git a/apps/server/src/provider/Layers/CodexSessionRuntime.ts b/apps/server/src/provider/Layers/CodexSessionRuntime.ts
index 20c918ca967..a80ab40d937 100644
--- a/apps/server/src/provider/Layers/CodexSessionRuntime.ts
+++ b/apps/server/src/provider/Layers/CodexSessionRuntime.ts
@@ -615,12 +615,12 @@ function readRouteFields(notification: CodexServerNotification): {
   }
 }
 
-function rememberCollabReceiverTurns(
-  collabReceiverTurns: Map<string, TurnId>,
+function rememberChildThreadTurns(
+  childThreadTurns: Map<string, TurnId>,
   notification: CodexServerNotification,
   parentTurnId: TurnId | undefined,
 ): void {
-  if (!parentTurnId) {
+  if (parentTurnId === undefined) {
     return;
   }
 
@@ -628,34 +628,47 @@ function rememberCollabReceiverTurns(
     return;
   }
 
-  if (notification.params.item.type !== "collabAgentToolCall") {
+  const item = notification.params.item;
+
+  if (item.type === "collabAgentToolCall") {
+    for (const receiverThreadId of item.receiverThreadIds) {
+      childThreadTurns.set(receiverThreadId, parentTurnId);
+    }
     return;
   }
 
-  for (const receiverThreadId of notification.params.item.receiverThreadIds) {
-    collabReceiverTurns.set(receiverThreadId, parentTurnId);
+  if (item.type === "subAgentActivity") {
+    childThreadTurns.set(item.agentThreadId, parentTurnId);
   }
 }
 
-function shouldSuppressChildConversationNotification(
-  method: CodexRpc.ServerNotificationMethod,
-): boolean {
-  return (
-    method === "thread/started" ||
-    method === "thread/status/changed" ||
-    method === "thread/archived" ||
-    method === "thread/unarchived" ||
-    method === "thread/closed" ||
-    method === "thread/compacted" ||
-    method === "thread/name/updated" ||
-    method === "thread/tokenUsage/updated" ||
-    method === "thread/goal/updated" ||
-    method === "thread/goal/cleared" ||
-    method === "turn/started" ||
-    method === "turn/completed" ||
-    method === "turn/plan/updated" ||
-    method === "item/plan/delta"
-  );
+function shouldKeepChildNotification(notification: CodexServerNotification): boolean {
+  switch (notification.method) {
+    case "item/started":
+    case "item/completed":
+      switch (notification.params.item.type) {
+        case "commandExecution":
+        case "fileChange":
+        case "mcpToolCall":
+        case "dynamicToolCall":
+        case "collabAgentToolCall":
+        case "webSearch":
+        case "imageView":
+          return true;
+        default:
+          return false;
+      }
+    case "item/commandExecution/outputDelta":
+    case "item/commandExecution/terminalInteraction":
+    case "item/fileChange/outputDelta":
+    case "item/fileChange/patchUpdated":
+    case "item/mcpToolCall/progress":
+    case "serverRequest/resolved":
+    case "turn/diff/updated":
+      return true;
+    default:
+      return false;
+  }
 }
 
 function toCodexUserInputAnswer(
@@ -739,7 +752,7 @@ export const makeCodexSessionRuntime = (
     const pendingApprovalsRef = yield* Ref.make(new Map<ApprovalRequestId, PendingApproval>());
     const approvalCorrelationsRef = yield* Ref.make(new Map<string, ApprovalCorrelation>());
     const pendingUserInputsRef = yield* Ref.make(new Map<ApprovalRequestId, PendingUserInput>());
-    const collabReceiverTurnsRef = yield* Ref.make(new Map<string, TurnId>());
+    const childThreadTurnsRef = yield* Ref.make(new Map<string, TurnId>());
     const closedRef = yield* Ref.make(false);
 
     // `~` is not shell-expanded when env vars are set via
@@ -856,27 +869,35 @@ export const makeCodexSessionRuntime = (
         ),
       );
 
+    const currentSessionProviderThreadId = Effect.map(Ref.get(sessionRef), currentProviderThreadId);
+
     const handleRawNotification = (notification: CodexServerNotification) =>
       Effect.gen(function* () {
         const payload = notification.params;
         const route = readRouteFields(notification);
-        const collabReceiverTurns = yield* Ref.get(collabReceiverTurnsRef);
-        const childParentTurnId = (() => {
-          const providerConversationId = readNotificationThreadId(notification);
-          return providerConversationId
-            ? collabReceiverTurns.get(providerConversationId)
-            : undefined;
-        })();
-
-        rememberCollabReceiverTurns(collabReceiverTurns, notification, route.turnId);
-        if (childParentTurnId && shouldSuppressChildConversationNotification(notification.method)) {
-          yield* Ref.set(collabReceiverTurnsRef, collabReceiverTurns);
+        const providerThreadId = readNotificationThreadId(notification);
+        const rootProviderThreadId = yield* currentSessionProviderThreadId;
+        const childThreadTurns = yield* Ref.get(childThreadTurnsRef);
+        const childParentTurnId =
+          providerThreadId === undefined ? undefined : childThreadTurns.get(providerThreadId);
+        const parentTurnId = childParentTurnId ?? route.turnId;
+
+        rememberChildThreadTurns(childThreadTurns, notification, parentTurnId);
+
+        const belongsToChild =
+          childParentTurnId !== undefined ||
+          (providerThreadId !== undefined &&
+            rootProviderThreadId !== undefined &&
+            providerThreadId !== rootProviderThreadId);
+
+        if (belongsToChild && !shouldKeepChildNotification(notification)) {
+          yield* Ref.set(childThreadTurnsRef, childThreadTurns);
           return;
         }
 
         let requestId: ApprovalRequestId | undefined;
         let requestKind: ProviderRequestKind | undefined;
-        let turnId = childParentTurnId ?? route.turnId;
+        let turnId = parentTurnId;
         let itemId = route.itemId;
 
         if (notification.method === "serverRequest/resolved") {
@@ -900,7 +921,7 @@ export const makeCodexSessionRuntime = (
           }
         }
 
-        yield* Ref.set(collabReceiverTurnsRef, collabReceiverTurns);
+        yield* Ref.set(childThreadTurnsRef, childThreadTurns);
         yield* emitEvent({
           kind: "notification",
           threadId: options.threadId,
@@ -916,8 +937,6 @@ export const makeCodexSessionRuntime = (
         });
       });
 
-    const currentSessionProviderThreadId = Effect.map(Ref.get(sessionRef), currentProviderThreadId);
-
     yield* client.handleServerNotification("thread/started", (payload) =>
       currentSessionProviderThreadId.pipe(
         Effect.flatMap((providerThreadId) => {