diff --git a/packages/agent-core-v2/docs/state-manifest.d.ts b/packages/agent-core-v2/docs/state-manifest.d.ts
index c8924cd53cb..0f3da92eff2 100644
--- a/packages/agent-core-v2/docs/state-manifest.d.ts
+++ b/packages/agent-core-v2/docs/state-manifest.d.ts
@@ -1137,6 +1137,7 @@ export interface AgentStateSnapshot {
     readonly kind: 'agent';
     readonly agentId?: string;
     readonly subagentType?: string;
+    readonly parentToolCallId?: string;
     readonly model?: string;
     readonly thinkingEffort?: string;
     readonly taskId: string;
diff --git a/packages/agent-core-v2/src/agent/tools/agent/agentTool.ts b/packages/agent-core-v2/src/agent/tools/agent/agentTool.ts
index 7401a36283d..fd8c4d625de 100644
--- a/packages/agent-core-v2/src/agent/tools/agent/agentTool.ts
+++ b/packages/agent-core-v2/src/agent/tools/agent/agentTool.ts
@@ -374,6 +374,7 @@ export class SubagentTool implements ISubagentTool {
     return {
       agentId,
       profileName,
+      parentToolCallId: toolCallId,
       model: displayModel,
       thinkingEffort: this.lifecycle
         .get(agentId)
diff --git a/packages/agent-core-v2/src/agent/tools/agent/subagent-task.ts b/packages/agent-core-v2/src/agent/tools/agent/subagent-task.ts
index 38cb41e0fa0..79a10ce1bb8 100644
--- a/packages/agent-core-v2/src/agent/tools/agent/subagent-task.ts
+++ b/packages/agent-core-v2/src/agent/tools/agent/subagent-task.ts
@@ -27,6 +27,7 @@ type SubagentCompletion = {
 export type SubagentHandle = {
   readonly agentId: string;
   readonly profileName: string;
+  readonly parentToolCallId?: string;
   readonly model?: string;
   readonly thinkingEffort?: string;
   readonly completion: Promise<SubagentCompletion>;
@@ -36,6 +37,7 @@ export interface SubagentTaskInfo extends AgentTaskInfoBase {
   readonly kind: 'agent';
   readonly agentId?: string;
   readonly subagentType?: string;
+  readonly parentToolCallId?: string;
   readonly model?: string;
   readonly thinkingEffort?: string;
 }
@@ -84,6 +86,7 @@ export class SubagentTask implements AgentTask {
   readonly idPrefix: string = 'agent';
   readonly agentId: string;
   readonly subagentType: string;
+  readonly parentToolCallId?: string;
   readonly model?: string;
   readonly thinkingEffort?: string;
 
@@ -94,6 +97,7 @@ export class SubagentTask implements AgentTask {
   ) {
     this.agentId = handle.agentId;
     this.subagentType = handle.profileName;
+    this.parentToolCallId = handle.parentToolCallId;
     this.model = handle.model;
     this.thinkingEffort = handle.thinkingEffort;
   }
@@ -129,6 +133,7 @@ export class SubagentTask implements AgentTask {
       kind: 'agent',
       agentId: this.agentId,
       subagentType: this.subagentType,
+      parentToolCallId: this.parentToolCallId,
       model: this.model,
       thinkingEffort: this.thinkingEffort,
     };
diff --git a/packages/agent-core-v2/test/agent/task/taskManager.test.ts b/packages/agent-core-v2/test/agent/task/taskManager.test.ts
index 3107a361371..4d12abd434c 100644
--- a/packages/agent-core-v2/test/agent/task/taskManager.test.ts
+++ b/packages/agent-core-v2/test/agent/task/taskManager.test.ts
@@ -85,6 +85,7 @@ function agentTask(
   options: {
     readonly agentId?: string;
     readonly subagentType?: string;
+    readonly parentToolCallId?: string;
     readonly abortController?: AbortController;
     readonly timeoutMs?: number;
   } = {},
@@ -92,6 +93,7 @@ function agentTask(
   const handle: SubagentHandle = {
     agentId: options.agentId ?? 'agent-child',
     profileName: options.subagentType ?? 'coder',
+    parentToolCallId: options.parentToolCallId,
     completion,
   };
   const task = new SubagentTask(
@@ -410,6 +412,7 @@ describe('AgentTaskService', () => {
       agentTask(new Promise(() => {}), 'investigate bug', {
         agentId: 'agent-child',
         subagentType: 'coder',
+        parentToolCallId: 'call-parent-1',
       }),
     );
 
@@ -420,6 +423,7 @@ describe('AgentTaskService', () => {
       description: 'investigate bug',
       agentId: 'agent-child',
       subagentType: 'coder',
+      parentToolCallId: 'call-parent-1',
       status: 'running',
     });
   });
diff --git a/packages/kap-server/src/protocol/task.ts b/packages/kap-server/src/protocol/task.ts
index e3e64681208..8e7bfd737d5 100644
--- a/packages/kap-server/src/protocol/task.ts
+++ b/packages/kap-server/src/protocol/task.ts
@@ -31,5 +31,7 @@ export const taskSchema = z.object({
   /** Subagent tasks only: the child's effective thinking effort at spawn. */
   thinking_effort: z.string().optional(),
   agent_id: z.string().optional(),
+  subagent_type: z.string().optional(),
+  parent_tool_call_id: z.string().optional(),
 });
 export type Task = z.infer<typeof taskSchema>;
diff --git a/packages/kap-server/src/routes/tasks.ts b/packages/kap-server/src/routes/tasks.ts
index dd22740f0e9..744b54e90e4 100644
--- a/packages/kap-server/src/routes/tasks.ts
+++ b/packages/kap-server/src/routes/tasks.ts
@@ -378,6 +378,12 @@ function toWireTask(
   if (info.kind === 'agent' && info.agentId !== undefined) {
     base.agent_id = info.agentId;
   }
+  if (info.kind === 'agent' && info.subagentType !== undefined) {
+    base.subagent_type = info.subagentType;
+  }
+  if (info.kind === 'agent' && info.parentToolCallId !== undefined) {
+    base.parent_tool_call_id = info.parentToolCallId;
+  }
   if (output !== undefined) {
     base.output_preview = output.preview;
     base.output_bytes = output.bytes;
diff --git a/packages/kap-server/test/tasks.test.ts b/packages/kap-server/test/tasks.test.ts
index 791b70cd07e..cd686ab87b4 100644
--- a/packages/kap-server/test/tasks.test.ts
+++ b/packages/kap-server/test/tasks.test.ts
@@ -36,6 +36,8 @@ interface TaskWire {
   output_preview?: string;
   output_bytes?: number;
   agent_id?: string;
+  subagent_type?: string;
+  parent_tool_call_id?: string;
 }
 
 interface ListWire {
@@ -159,6 +161,7 @@ describe('server-v2 /api/v1/sessions/{sid}/tasks', () => {
               kind: 'agent',
               agentId: 'sub-1',
               subagentType: 'explore',
+              parentToolCallId: 'call-parent-1',
               model: 'provider/secondary',
               thinkingEffort: 'low',
             };
@@ -216,6 +219,8 @@ describe('server-v2 /api/v1/sessions/{sid}/tasks', () => {
       model: 'provider/secondary', // subagent tasks expose the bound display model
       thinking_effort: 'low', // …and its effective thinking effort
       agent_id: 'sub-1',
+      subagent_type: 'explore',
+      parent_tool_call_id: 'call-parent-1',
     });
     expect(byId.get(agentId)?.command).toBeUndefined();
 
@@ -227,6 +232,10 @@ describe('server-v2 /api/v1/sessions/{sid}/tasks', () => {
     });
     expect(byId.get(processId)?.agent_id).toBeUndefined();
     expect(byId.get(questionId)?.agent_id).toBeUndefined();
+    expect(byId.get(processId)?.subagent_type).toBeUndefined();
+    expect(byId.get(questionId)?.subagent_type).toBeUndefined();
+    expect(byId.get(processId)?.parent_tool_call_id).toBeUndefined();
+    expect(byId.get(questionId)?.parent_tool_call_id).toBeUndefined();
   });
 
   it('filters the list by wire status', async () => {
@@ -264,6 +273,8 @@ describe('server-v2 /api/v1/sessions/{sid}/tasks', () => {
       session_id: id,
       kind: 'subagent',
       agent_id: 'sub-1',
+      subagent_type: 'explore',
+      parent_tool_call_id: 'call-parent-1',
     });
 
     const missing = await getJson<null>(`/api/v1/sessions/${id}/tasks/nope`);