diff --git a/extensions/voice-call/src/response-generator.test.ts b/extensions/voice-call/src/response-generator.test.ts
index f508297b8a7..83e37dd4936 100644
--- a/extensions/voice-call/src/response-generator.test.ts
+++ b/extensions/voice-call/src/response-generator.test.ts
@@ -3,14 +3,31 @@ import { VoiceCallConfigSchema } from "./config.js";
 import type { CoreAgentDeps, CoreConfig } from "./core-bridge.js";
 import { generateVoiceResponse } from "./response-generator.js";
 
+type TestSessionEntry = {
+  sessionId: string;
+  updatedAt: number;
+  providerOverride?: string;
+  modelOverride?: string;
+  modelOverrideSource?: string;
+};
+
+type EmbeddedAgentArgs = {
+  extraSystemPrompt: string;
+  provider?: string;
+  model?: string;
+  sessionKey?: string;
+  sandboxSessionKey?: string;
+  agentDir?: string;
+  agentId?: string;
+  workspaceDir?: string;
+  sessionFile?: string;
+};
+
 function createAgentRuntime(payloads: Array<Record<string, unknown>>) {
-  const sessionStore: Record<string, { sessionId: string; updatedAt: number }> = {};
+  const sessionStore: Record<string, TestSessionEntry> = {};
   const saveSessionStore = vi.fn(async () => {});
   const updateSessionStore = vi.fn(
-    async (
-      _storePath: string,
-      mutator: (store: Record<string, { sessionId: string; updatedAt: number }>) => unknown,
-    ) => {
+    async (_storePath: string, mutator: (store: Record<string, TestSessionEntry>) => unknown) => {
       return await mutator(sessionStore);
     },
   );
@@ -77,17 +94,11 @@ function requireEmbeddedAgentArgs(runEmbeddedPiAgent: ReturnType<typeof vi.fn>)
   if (!firstCall) {
     throw new Error("voice response generator did not invoke the embedded agent");
   }
-  const args = firstCall[0] as
-    | {
-        extraSystemPrompt?: string;
-        provider?: string;
-        model?: string;
-      }
-    | undefined;
+  const args = firstCall[0] as Partial<EmbeddedAgentArgs> | undefined;
   if (!args?.extraSystemPrompt) {
     throw new Error("voice response generator did not pass the spoken-output contract prompt");
   }
-  return args;
+  return args as EmbeddedAgentArgs;
 }
 
 async function runGenerateVoiceResponse(
@@ -186,21 +197,17 @@ describe("generateVoiceResponse", () => {
     });
 
     expect(result.text).toBe("Pinned model works.");
-    expect(sessionStore["voice:15550001111"]).toMatchObject({
-      providerOverride: "openai",
-      modelOverride: "gpt-4.1-nano",
-      modelOverrideSource: "auto",
-    });
+    const pinnedSessionEntry = sessionStore["voice:15550001111"];
+    expect(pinnedSessionEntry?.providerOverride).toBe("openai");
+    expect(pinnedSessionEntry?.modelOverride).toBe("gpt-4.1-nano");
+    expect(pinnedSessionEntry?.modelOverrideSource).toBe("auto");
     const updateSessionStoreCall = updateSessionStore.mock.calls[0];
     expect(updateSessionStoreCall?.[0]).toBe("/tmp/openclaw/main/sessions.json");
     expect(updateSessionStoreCall?.[1]).toBeTypeOf("function");
-    expect(runEmbeddedPiAgent).toHaveBeenCalledWith(
-      expect.objectContaining({
-        provider: "openai",
-        model: "gpt-4.1-nano",
-        sessionKey: "voice:15550001111",
-      }),
-    );
+    const args = requireEmbeddedAgentArgs(runEmbeddedPiAgent);
+    expect(args.provider).toBe("openai");
+    expect(args.model).toBe("gpt-4.1-nano");
+    expect(args.sessionKey).toBe("voice:15550001111");
   });
 
   it("uses the persisted per-call session key for classic responses", async () => {
@@ -224,16 +231,13 @@ describe("generateVoiceResponse", () => {
     });
 
     expect(result.text).toBe("Fresh call context.");
-    expect(sessionStore["voice:call:call-123"]).toMatchObject({
-      sessionId: expect.stringMatching(/\S/),
-    });
+    const perCallSessionEntry = sessionStore["voice:call:call-123"];
+    expect(perCallSessionEntry?.sessionId).toBeTypeOf("string");
+    expect(perCallSessionEntry?.sessionId).not.toBe("");
     expect(sessionStore["voice:15550001111"]).toBeUndefined();
-    expect(runEmbeddedPiAgent).toHaveBeenCalledWith(
-      expect.objectContaining({
-        sessionKey: "voice:call:call-123",
-        sandboxSessionKey: "agent:main:voice:call:call-123",
-      }),
-    );
+    const args = requireEmbeddedAgentArgs(runEmbeddedPiAgent);
+    expect(args.sessionKey).toBe("voice:call:call-123");
+    expect(args.sandboxSessionKey).toBe("agent:main:voice:call:call-123");
   });
 
   it("uses the main agent workspace when voice config omits agentId", async () => {
@@ -272,15 +276,12 @@ describe("generateVoiceResponse", () => {
         agentId: "main",
       },
     );
-    expect(runEmbeddedPiAgent).toHaveBeenCalledWith(
-      expect.objectContaining({
-        agentDir: "/tmp/openclaw/agents/main",
-        agentId: "main",
-        sandboxSessionKey: "agent:main:voice:15550001111",
-        workspaceDir: "/tmp/openclaw/workspace/main",
-        sessionFile: "/tmp/openclaw/main/sessions/session.jsonl",
-      }),
-    );
+    const args = requireEmbeddedAgentArgs(runEmbeddedPiAgent);
+    expect(args.agentDir).toBe("/tmp/openclaw/agents/main");
+    expect(args.agentId).toBe("main");
+    expect(args.sandboxSessionKey).toBe("agent:main:voice:15550001111");
+    expect(args.workspaceDir).toBe("/tmp/openclaw/workspace/main");
+    expect(args.sessionFile).toBe("/tmp/openclaw/main/sessions/session.jsonl");
   });
 
   it("uses the configured voice response agent workspace", async () => {
@@ -323,14 +324,11 @@ describe("generateVoiceResponse", () => {
         agentId: "voice",
       },
     );
-    expect(runEmbeddedPiAgent).toHaveBeenCalledWith(
-      expect.objectContaining({
-        agentDir: "/tmp/openclaw/agents/voice",
-        agentId: "voice",
-        sandboxSessionKey: "agent:voice:voice:15550001111",
-        workspaceDir: "/tmp/openclaw/workspace/voice",
-        sessionFile: "/tmp/openclaw/voice/sessions/session.jsonl",
-      }),
-    );
+    const args = requireEmbeddedAgentArgs(runEmbeddedPiAgent);
+    expect(args.agentDir).toBe("/tmp/openclaw/agents/voice");
+    expect(args.agentId).toBe("voice");
+    expect(args.sandboxSessionKey).toBe("agent:voice:voice:15550001111");
+    expect(args.workspaceDir).toBe("/tmp/openclaw/workspace/voice");
+    expect(args.sessionFile).toBe("/tmp/openclaw/voice/sessions/session.jsonl");
   });
 });