diff --git a/extensions/codex/src/app-server/approval-bridge.test.ts b/extensions/codex/src/app-server/approval-bridge.test.ts
index 4742d227ce0..9efcffac8d4 100644
--- a/extensions/codex/src/app-server/approval-bridge.test.ts
+++ b/extensions/codex/src/app-server/approval-bridge.test.ts
@@ -107,12 +107,8 @@ describe("Codex app-server approval bridge", () => {
     expect(requestPayload.turnSourceChannel).toBe("telegram");
     expect(requestPayload.turnSourceTo).toBe("chat-1");
     expect(gatewayCallOptions()).toEqual({ expectFinal: false });
-    expect(
-      findApprovalEvent(params, { status: "pending", approvalId: "plugin:approval-1" }),
-    ).toBeDefined();
-    expect(
-      findApprovalEvent(params, { status: "approved", approvalId: "plugin:approval-1" }),
-    ).toBeDefined();
+    findApprovalEvent(params, { status: "pending", approvalId: "plugin:approval-1" });
+    findApprovalEvent(params, { status: "approved", approvalId: "plugin:approval-1" });
   });
 
   it("describes command approvals from parsed command actions when available", async () => {
@@ -240,12 +236,10 @@ describe("Codex app-server approval bridge", () => {
     expect(gatewayRequestPayload().description).toBe(
       "Command: pnpm test --watch extensions/codex/src/app-server\nSession: agent:main:session-1",
     );
-    expect(
-      findApprovalEvent(params, {
-        status: "pending",
-        command: "pnpm test --watch extensions/codex/src/app-server",
-      }),
-    ).toBeDefined();
+    findApprovalEvent(params, {
+      status: "pending",
+      command: "pnpm test --watch extensions/codex/src/app-server",
+    });
   });
 
   it("escapes command approval previews before forwarding approval text and events", async () => {
@@ -275,12 +269,9 @@ describe("Codex app-server approval bridge", () => {
     expect(description).not.toContain("<@U123>");
     expect(description).not.toContain("[trusted](https://evil)");
     expect(description).not.toContain("@here");
-    expect(
-      findApprovalEvent(params, {
-        command:
-          "printf '&lt;\uff20U123&gt; \uff3btrusted\uff3d\uff08https://evil\uff09 \uff20here'",
-      }),
-    ).toBeDefined();
+    findApprovalEvent(params, {
+      command: "printf '&lt;\uff20U123&gt; \uff3btrusted\uff3d\uff08https://evil\uff09 \uff20here'",
+    });
   });
 
   it("preserves visible OSC-8 link labels in command previews", async () => {
@@ -416,12 +407,10 @@ describe("Codex app-server approval bridge", () => {
       "plugin.approval.request",
       "plugin.approval.waitDecision",
     ]);
-    expect(
-      findApprovalEvent(params, {
-        status: "denied",
-        approvalId: "plugin:approval-untrusted",
-      }),
-    ).toBeDefined();
+    findApprovalEvent(params, {
+      status: "denied",
+      approvalId: "plugin:approval-untrusted",
+    });
   });
 
   it("only treats own null data-property request decisions as no-route", async () => {
@@ -538,9 +527,7 @@ describe("Codex app-server approval bridge", () => {
 
     expect(result).toEqual({ decision: "decline" });
     expect(mockCallGatewayTool).toHaveBeenCalledTimes(1);
-    expect(
-      findApprovalEvent(params, { status: "unavailable", reason: "needs write access" }),
-    ).toBeDefined();
+    findApprovalEvent(params, { status: "unavailable", reason: "needs write access" });
   });
 
   it("sanitizes reason previews before forwarding approval text and events", async () => {
@@ -566,12 +553,10 @@ describe("Codex app-server approval bridge", () => {
     expect(gatewayRequestPayload().description).toBe(
       "Reason: needs write access for /tmp please\nSession: agent:main:session-1",
     );
-    expect(
-      findApprovalEvent(params, {
-        status: "unavailable",
-        reason: "needs write access for /tmp please",
-      }),
-    ).toBeDefined();
+    findApprovalEvent(params, {
+      status: "unavailable",
+      reason: "needs write access for /tmp please",
+    });
   });
 
   it("fails closed for unsupported native approval methods without requesting plugin approval", async () => {
diff --git a/extensions/diffs/src/tool.test.ts b/extensions/diffs/src/tool.test.ts
index e778c73128b..42a07417c6b 100644
--- a/extensions/diffs/src/tool.test.ts
+++ b/extensions/diffs/src/tool.test.ts
@@ -236,7 +236,8 @@ describe("diffs tool", () => {
         mode: "file",
       });
       const filePath = (result?.details as Record<string, unknown>).filePath as string;
-      await expect(fs.stat(filePath)).resolves.toBeDefined();
+      const stat = await fs.stat(filePath);
+      expect(stat.isFile()).toBe(true);
 
       vi.setSystemTime(new Date(now.getTime() + 61_000));
       await store.cleanupExpired();
diff --git a/extensions/discord/src/voice/manager.e2e.test.ts b/extensions/discord/src/voice/manager.e2e.test.ts
index 5a8b4d74529..fbf9fada47f 100644
--- a/extensions/discord/src/voice/manager.e2e.test.ts
+++ b/extensions/discord/src/voice/manager.e2e.test.ts
@@ -2783,9 +2783,13 @@ describe("DiscordVoiceManager", () => {
     expect(lastTtsStreamArgs().disableFallback).toBe(true);
     expect(lastTtsStreamArgs().text).toBe("hello back");
     expect(textToSpeechMock).not.toHaveBeenCalled();
-    expect(
-      lastMockCall(createAudioResourceMock as unknown as MockCallSource, "audio resource")[0],
-    ).toBeDefined();
+    const audioResourceInput = lastMockCall(
+      createAudioResourceMock as unknown as MockCallSource,
+      "audio resource",
+    )[0];
+    if (audioResourceInput === undefined) {
+      throw new Error("expected Discord audio resource input");
+    }
     await vi.waitFor(() => expect(release).toHaveBeenCalledTimes(1));
   });
 
diff --git a/extensions/qa-lab/src/live-transports/telegram/telegram-live.runtime.test.ts b/extensions/qa-lab/src/live-transports/telegram/telegram-live.runtime.test.ts
index 67408949230..bafaa948078 100644
--- a/extensions/qa-lab/src/live-transports/telegram/telegram-live.runtime.test.ts
+++ b/extensions/qa-lab/src/live-transports/telegram/telegram-live.runtime.test.ts
@@ -413,11 +413,6 @@ describe("telegram live qa runtime", () => {
         .find((scenario) => scenario.id === "telegram-mentioned-message-reply")
         ?.buildRun("sut_bot").steps[0].replyToLatestSutMessage,
     ).toBe(true);
-    expect(
-      scenarios
-        .find((scenario) => scenario.id === "telegram-reply-chain-exact-marker")
-        ?.buildRun("sut_bot").steps[0],
-    ).toBeDefined();
     const replyChainStep = requireScenario(scenarios, "telegram-reply-chain-exact-marker").buildRun(
       "sut_bot",
     ).steps[0];
diff --git a/extensions/whatsapp/src/auto-reply/deliver-reply.test.ts b/extensions/whatsapp/src/auto-reply/deliver-reply.test.ts
index c703d291bdf..2533eec893b 100644
--- a/extensions/whatsapp/src/auto-reply/deliver-reply.test.ts
+++ b/extensions/whatsapp/src/auto-reply/deliver-reply.test.ts
@@ -458,9 +458,7 @@ describe("deliverWebReply", () => {
     expect(mediaPayload.mimetype).toBe("image/jpeg");
     expect(mockCallArg(msg.sendMedia, 0, 1, "sendMedia")).toBeUndefined();
     expect(msg.reply).toHaveBeenCalledWith("aaa", undefined);
-    expect(
-      findLoggerContext(replyLogger.info, "auto-reply sent (media)", "replyLogger.info"),
-    ).toBeDefined();
+    findLoggerContext(replyLogger.info, "auto-reply sent (media)", "replyLogger.info");
     expect(logVerbose).toHaveBeenCalled();
   });
 
diff --git a/src/acp/translator.stop-reason.test.ts b/src/acp/translator.stop-reason.test.ts
index e224614305b..59392a73909 100644
--- a/src/acp/translator.stop-reason.test.ts
+++ b/src/acp/translator.stop-reason.test.ts
@@ -331,7 +331,11 @@ describe("acp translator stop reason mapping", () => {
       await Promise.resolve();
       agent.handleGatewayDisconnect("1006: first disconnect");
       agent.handleGatewayReconnect();
-      await vi.waitFor(() => expect(resolveAgentWait).toBeDefined());
+      await vi.waitFor(() => {
+        if (resolveAgentWait === undefined) {
+          throw new Error("expected agent.wait resolver");
+        }
+      });
       const resolveWait = requireValue(resolveAgentWait, "agent.wait resolver");
 
       agent.handleGatewayDisconnect("1006: second disconnect");
diff --git a/src/plugins/loader.test.ts b/src/plugins/loader.test.ts
index 25446ae4a24..c39ed0726b1 100644
--- a/src/plugins/loader.test.ts
+++ b/src/plugins/loader.test.ts
@@ -5433,11 +5433,11 @@ module.exports = {
       },
     });
 
-    expect(
-      registry.channels.find((entry) => entry.plugin.id === "healthy-chat")?.plugin.meta,
-    ).toBeDefined();
     const healthyMeta = registry.channels.find((entry) => entry.plugin.id === "healthy-chat")
       ?.plugin.meta;
+    if (!healthyMeta) {
+      throw new Error("expected healthy chat plugin metadata");
+    }
     expect(healthyMeta?.label).toBe("Healthy Chat");
     expect(healthyMeta?.docsPath).toBe("/channels/healthy-chat");
     expect(registry.plugins.find((entry) => entry.id === "healthy-channel")?.status).toBe("loaded");