diff --git a/extensions/amazon-bedrock/discovery.test.ts b/extensions/amazon-bedrock/discovery.test.ts
index 5dde8981417..ed10a995654 100644
--- a/extensions/amazon-bedrock/discovery.test.ts
+++ b/extensions/amazon-bedrock/discovery.test.ts
@@ -31,9 +31,9 @@ function mockSingleActiveSummary(overrides: Partial<typeof baseActiveAnthropicSu
 }
 
 function expectModelFields(model: unknown, expected: Record<string, unknown>): void {
-  expect(model).toBeDefined();
-  expect(typeof model).toBe("object");
-  expect(model).not.toBeNull();
+  if (!model || typeof model !== "object") {
+    throw new Error("Expected model record");
+  }
   const actual = model as Record<string, unknown>;
   for (const [key, value] of Object.entries(expected)) {
     expect(actual[key]).toEqual(value);
diff --git a/extensions/google/speech-provider.test.ts b/extensions/google/speech-provider.test.ts
index 3c541ca9499..7a4fc914cd7 100644
--- a/extensions/google/speech-provider.test.ts
+++ b/extensions/google/speech-provider.test.ts
@@ -56,9 +56,9 @@ function installGoogleTtsRequestMock(pcm = Buffer.from([1, 0, 2, 0])) {
 }
 
 function expectRecordFields(value: unknown, expected: Record<string, unknown>) {
-  expect(value).toBeDefined();
-  expect(typeof value).toBe("object");
-  expect(value).not.toBeNull();
+  if (!value || typeof value !== "object") {
+    throw new Error("Expected record");
+  }
   const actual = value as Record<string, unknown>;
   for (const [key, expectedValue] of Object.entries(expected)) {
     expect(actual[key]).toEqual(expectedValue);
diff --git a/extensions/lmstudio/src/stream.test.ts b/extensions/lmstudio/src/stream.test.ts
index bb4a0494e02..8ef2168dc45 100644
--- a/extensions/lmstudio/src/stream.test.ts
+++ b/extensions/lmstudio/src/stream.test.ts
@@ -83,7 +83,9 @@ function expectBaseStreamModelFields(baseStream: StreamFn, fields: Record<string
     "base stream",
   );
   expectRecordFields(requireRecord(call[0], "base stream model"), fields);
-  expect(call[1]).toBeDefined();
+  if (call[1] === undefined) {
+    throw new Error("Expected base stream context");
+  }
   expect(call[2]).toBeUndefined();
 }
 
diff --git a/extensions/zai/index.test.ts b/extensions/zai/index.test.ts
index ff0c8ad1d66..a46760be91c 100644
--- a/extensions/zai/index.test.ts
+++ b/extensions/zai/index.test.ts
@@ -24,9 +24,11 @@ function expectReplayPolicyFields(
   policy: Record<string, unknown> | undefined,
   fields: Record<string, unknown>,
 ): void {
-  expect(policy).toBeDefined();
+  if (!policy) {
+    throw new Error("Expected replay policy");
+  }
   for (const [key, value] of Object.entries(fields)) {
-    expect(policy?.[key]).toEqual(value);
+    expect(policy[key]).toEqual(value);
   }
 }
 
@@ -34,9 +36,11 @@ function expectModelFields(
   model: Record<string, unknown> | undefined,
   fields: Record<string, unknown>,
 ): void {
-  expect(model).toBeDefined();
+  if (!model) {
+    throw new Error("Expected provider model");
+  }
   for (const [key, value] of Object.entries(fields)) {
-    expect(model?.[key]).toEqual(value);
+    expect(model[key]).toEqual(value);
   }
 }