diff --git a/src/agents/sessions-spawn-hooks.test.ts b/src/agents/sessions-spawn-hooks.test.ts
index 88d514de2ed..f8dc07ed3f6 100644
--- a/src/agents/sessions-spawn-hooks.test.ts
+++ b/src/agents/sessions-spawn-hooks.test.ts
@@ -54,6 +54,19 @@ function findGatewayRequest(method: string): GatewayRequest | undefined {
   return getGatewayRequests().find((request) => request.method === method);
 }
 
+function requireRecord(value: unknown, label: string): Record<string, unknown> {
+  expect(value, label).toBeTypeOf("object");
+  expect(value, label).not.toBeNull();
+  return value as Record<string, unknown>;
+}
+
+function expectFields(value: unknown, expected: Record<string, unknown>, label = "object"): void {
+  const record = requireRecord(value, label);
+  for (const [key, expectedValue] of Object.entries(expected)) {
+    expect(record[key], `${label}.${key}`).toEqual(expectedValue);
+  }
+}
+
 function setConfig(next: Record<string, unknown>) {
   hoisted.configOverride = createSubagentSpawnTestConfig(undefined, next);
 }
@@ -132,10 +145,14 @@ function expectThreadBindFailureCleanup(
   expect(hookRunnerMocks.runSubagentSpawned).not.toHaveBeenCalled();
   expectSessionsDeleteWithoutAgentStart();
   const deleteCall = findGatewayRequest("sessions.delete");
-  expect(deleteCall?.params).toMatchObject({
-    key: result.childSessionKey,
-    emitLifecycleHooks: false,
-  });
+  expectFields(
+    deleteCall?.params,
+    {
+      key: result.childSessionKey,
+      emitLifecycleHooks: false,
+    },
+    "delete params",
+  );
 }
 
 beforeAll(async () => {
@@ -215,7 +232,7 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       context: "isolated",
     });
 
-    expect(result).toMatchObject({ status: "accepted", runId: "run-1" });
+    expectFields(result, { status: "accepted", runId: "run-1" }, "spawn result");
     expect(hookRunnerMocks.runSubagentSpawning).toHaveBeenCalledTimes(1);
     expect(hookRunnerMocks.runSubagentSpawning).toHaveBeenCalledWith(
       {
@@ -242,25 +259,37 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       Record<string, unknown>,
       Record<string, unknown>,
     ];
-    expect(event).toMatchObject({
-      runId: "run-1",
-      agentId: "main",
-      label: "research",
-      mode: "session",
-      requester: {
+    expectFields(
+      event,
+      {
+        runId: "run-1",
+        agentId: "main",
+        label: "research",
+        mode: "session",
+        threadRequested: true,
+      },
+      "spawned event",
+    );
+    expectFields(
+      event.requester,
+      {
         channel: "discord",
         accountId: "work",
         to: "channel:123",
         threadId: 456,
       },
-      threadRequested: true,
-    });
+      "spawned requester",
+    );
     expect(event.childSessionKey).toEqual(expect.stringMatching(/^agent:main:subagent:/));
-    expect(ctx).toMatchObject({
-      runId: "run-1",
-      requesterSessionKey: "main",
-      childSessionKey: event.childSessionKey,
-    });
+    expectFields(
+      ctx,
+      {
+        runId: "run-1",
+        requesterSessionKey: "main",
+        childSessionKey: event.childSessionKey,
+      },
+      "spawned context",
+    );
   });
 
   it("emits subagent_spawned with threadRequested=false when not requested", async () => {
@@ -269,20 +298,28 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       agentTo: "channel:123",
     });
 
-    expect(result).toMatchObject({ status: "accepted", runId: "run-1" });
+    expectFields(result, { status: "accepted", runId: "run-1" }, "spawn result");
     expect(hookRunnerMocks.runSubagentSpawning).not.toHaveBeenCalled();
     expect(hookRunnerMocks.runSubagentSpawned).toHaveBeenCalledTimes(1);
     const [event] = (hookRunnerMocks.runSubagentSpawned.mock.calls[0] ?? []) as unknown as [
       Record<string, unknown>,
     ];
-    expect(event).toMatchObject({
-      mode: "run",
-      threadRequested: false,
-      requester: {
+    expectFields(
+      event,
+      {
+        mode: "run",
+        threadRequested: false,
+      },
+      "spawned event",
+    );
+    expectFields(
+      event.requester,
+      {
         channel: "discord",
         to: "channel:123",
       },
-    });
+      "spawned requester",
+    );
   });
 
   it("respects explicit mode=run when thread binding is requested", async () => {
@@ -294,13 +331,17 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       context: "isolated",
     });
 
-    expect(result).toMatchObject({ status: "accepted", runId: "run-1", mode: "run" });
+    expectFields(result, { status: "accepted", runId: "run-1", mode: "run" }, "spawn result");
     expect(hookRunnerMocks.runSubagentSpawning).toHaveBeenCalledTimes(1);
     const event = getSpawnedEventCall();
-    expect(event).toMatchObject({
-      mode: "run",
-      threadRequested: true,
-    });
+    expectFields(
+      event,
+      {
+        mode: "run",
+        threadRequested: true,
+      },
+      "spawned event",
+    );
   });
 
   it("returns error when thread binding cannot be created", async () => {
@@ -377,26 +418,34 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       context: "isolated",
     });
 
-    expect(result).toMatchObject({ status: "error" });
+    expect(result.status).toBe("error");
     expect(hookRunnerMocks.runSubagentEnded).toHaveBeenCalledTimes(1);
     const [event] = (hookRunnerMocks.runSubagentEnded.mock.calls[0] ?? []) as unknown as [
       Record<string, unknown>,
     ];
-    expect(event).toMatchObject({
-      targetSessionKey: expect.stringMatching(/^agent:main:subagent:/),
-      accountId: "work",
-      targetKind: "subagent",
-      reason: "spawn-failed",
-      sendFarewell: true,
-      outcome: "error",
-      error: "Session failed to start",
-    });
+    expect(event.targetSessionKey).toEqual(expect.stringMatching(/^agent:main:subagent:/));
+    expectFields(
+      event,
+      {
+        accountId: "work",
+        targetKind: "subagent",
+        reason: "spawn-failed",
+        sendFarewell: true,
+        outcome: "error",
+        error: "Session failed to start",
+      },
+      "ended event",
+    );
     const deleteCall = findGatewayRequest("sessions.delete");
-    expect(deleteCall?.params).toMatchObject({
-      key: event.targetSessionKey,
-      deleteTranscript: true,
-      emitLifecycleHooks: false,
-    });
+    expectFields(
+      deleteCall?.params,
+      {
+        key: event.targetSessionKey,
+        deleteTranscript: true,
+        emitLifecycleHooks: false,
+      },
+      "delete params",
+    );
   });
 
   it("falls back to sessions.delete cleanup when subagent_ended hook is unavailable", async () => {
@@ -411,15 +460,19 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
       context: "isolated",
     });
 
-    expect(result).toMatchObject({ status: "error" });
+    expect(result.status).toBe("error");
     expect(hookRunnerMocks.runSubagentEnded).not.toHaveBeenCalled();
     const methods = getGatewayMethods();
     expect(methods).toContain("sessions.delete");
     const deleteCall = findGatewayRequest("sessions.delete");
-    expect(deleteCall?.params).toMatchObject({
-      deleteTranscript: true,
-      emitLifecycleHooks: true,
-    });
+    expectFields(
+      deleteCall?.params,
+      {
+        deleteTranscript: true,
+        emitLifecycleHooks: true,
+      },
+      "delete params",
+    );
   });
 
   it("cleans up the provisional session when lineage patching fails after thread binding", async () => {
@@ -464,10 +517,14 @@ describe("sessions_spawn subagent lifecycle hooks", () => {
     expect(methods).toContain("sessions.delete");
     expect(methods).not.toContain("agent");
     const deleteCall = findGatewayRequest("sessions.delete");
-    expect(deleteCall?.params).toMatchObject({
-      key: result.childSessionKey,
-      deleteTranscript: true,
-      emitLifecycleHooks: true,
-    });
+    expectFields(
+      deleteCall?.params,
+      {
+        key: result.childSessionKey,
+        deleteTranscript: true,
+        emitLifecycleHooks: true,
+      },
+      "delete params",
+    );
   });
 });