fix: surface llm workflow errors

src/lib/llm/__tests__/client.test.ts

@@ -16,16 +16,16 @@ describe("generateValidatedJson", () => {
     vi.restoreAllMocks();
   });
 
-  it("returns null when no provider key is configured", async () => {
+  it("throws clearly when no provider key is configured", async () => {
     process.env.LLM_PROVIDER = "deepseek";
     delete process.env.DEEPSEEK_API_KEY;
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      prompt: "Return JSON.",
-    });
-
-    expect(result).toBeNull();
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        prompt: "Return JSON.",
+      }),
+    ).rejects.toThrow("DEEPSEEK_API_KEY is missing");
   });
 
   it("returns parsed data when the model response matches the schema", async () => {
@@ -41,32 +41,32 @@ describe("generateValidatedJson", () => {
     expect(result).toEqual({ value: "from-llm" });
   });
 
-  it("returns null when the model response fails schema validation", async () => {
+  it("throws clearly when the model response fails schema validation", async () => {
     process.env.LLM_PROVIDER = "deepseek";
     process.env.DEEPSEEK_API_KEY = "test-key";
     client.setGenerateJsonForValidation(async () => ({ value: 42 }));
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      prompt: "Return JSON.",
-    });
-
-    expect(result).toBeNull();
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        prompt: "Return JSON.",
+      }),
+    ).rejects.toThrow("LLM response failed schema validation");
   });
 
-  it("returns null when the provider call rejects", async () => {
+  it("throws clearly when the provider call rejects", async () => {
     process.env.LLM_PROVIDER = "deepseek";
     process.env.DEEPSEEK_API_KEY = "test-key";
     client.setGenerateJsonForValidation(async () => {
       throw new Error("provider down");
     });
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      prompt: "Return JSON.",
-    });
-
-    expect(result).toBeNull();
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        prompt: "Return JSON.",
+      }),
+    ).rejects.toThrow("provider down");
   });
 
   it("logs validation success with the supplied task label", async () => {
@@ -93,13 +93,13 @@ describe("generateValidatedJson", () => {
     process.env.DEEPSEEK_API_KEY = "test-key";
     client.setGenerateJsonForValidation(async () => ({ value: 42 }));
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      prompt: "Return JSON.",
-      task: "fact_extractor",
-    });
-
-    expect(result).toBeNull();
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        prompt: "Return JSON.",
+        task: "fact_extractor",
+      }),
+    ).rejects.toThrow("LLM response failed schema validation");
     expect(warnSpy).toHaveBeenCalledWith(
       expect.stringContaining("[llm:validated] task=fact_extractor ok=false"),
     );
@@ -150,16 +150,16 @@ describe("generateValidatedJson", () => {
     const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
     client.setGenerateJsonForValidation(async () => ({ value: 42 }));
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      task: "fact_extractor",
-      prompt: "Return JSON.",
-    });
-
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        task: "fact_extractor",
+        prompt: "Return JSON.",
+      }),
+    ).rejects.toThrow("LLM response failed schema validation");
     const allLogs = [...infoSpy.mock.calls, ...warnSpy.mock.calls]
       .flat()
       .join("\n");
-    expect(result).toBeNull();
     expect(allLogs).toContain("[llm:validated] task=fact_extractor ok=false");
     expect(allLogs).toContain("zod_error=");
     expect(allLogs).not.toContain("super-secret-key");
@@ -173,13 +173,13 @@ describe("generateValidatedJson", () => {
       throw new Error("provider unavailable");
     });
 
-    const result = await client.generateValidatedJson({
-      schema: z.object({ value: z.string() }),
-      task: "quality_inspector",
-      prompt: "Return JSON.",
-    });
-
-    expect(result).toBeNull();
+    await expect(
+      client.generateValidatedJson({
+        schema: z.object({ value: z.string() }),
+        task: "quality_inspector",
+        prompt: "Return JSON.",
+      }),
+    ).rejects.toThrow("provider unavailable");
     expect(warnSpy).toHaveBeenCalledWith(
       expect.stringContaining("[llm:error] task=quality_inspector"),
     );