feat: add central llm runtime logging

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

@@ -7,12 +7,12 @@ describe("generateValidatedJson", () => {
   const originalProvider = process.env.LLM_PROVIDER;
   const originalDeepSeekKey = process.env.DEEPSEEK_API_KEY;
 
-    afterEach(() => {
-      process.env.LLM_PROVIDER = originalProvider;
-      process.env.DEEPSEEK_API_KEY = originalDeepSeekKey;
-      client.setGenerateJsonForValidation(client.generateJson);
-      vi.restoreAllMocks();
-    });
+  afterEach(() => {
+    process.env.LLM_PROVIDER = originalProvider;
+    process.env.DEEPSEEK_API_KEY = originalDeepSeekKey;
+    client.setGenerateJsonForValidation(client.generateJson);
+    vi.restoreAllMocks();
+  });
 
   it("returns null when no provider key is configured", async () => {
     process.env.LLM_PROVIDER = "deepseek";
@@ -26,10 +26,10 @@ describe("generateValidatedJson", () => {
     expect(result).toBeNull();
   });
 
-    it("returns parsed data when the model response matches the schema", async () => {
-      process.env.LLM_PROVIDER = "deepseek";
-      process.env.DEEPSEEK_API_KEY = "test-key";
-      client.setGenerateJsonForValidation(async () => ({ value: "from-llm" }));
+  it("returns parsed data when the model response matches the schema", async () => {
+    process.env.LLM_PROVIDER = "deepseek";
+    process.env.DEEPSEEK_API_KEY = "test-key";
+    client.setGenerateJsonForValidation(async () => ({ value: "from-llm" }));
 
     const result = await client.generateValidatedJson({
       schema: z.object({ value: z.string() }),
@@ -39,10 +39,10 @@ describe("generateValidatedJson", () => {
     expect(result).toEqual({ value: "from-llm" });
   });
 
-    it("returns null 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 }));
+  it("returns null 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() }),
@@ -52,12 +52,12 @@ describe("generateValidatedJson", () => {
     expect(result).toBeNull();
   });
 
-    it("returns null 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");
-      });
+  it("returns null 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() }),
@@ -66,4 +66,104 @@ describe("generateValidatedJson", () => {
 
     expect(result).toBeNull();
   });
+
+  it("logs validation success with the supplied task label", async () => {
+    const infoSpy = vi.spyOn(console, "info").mockImplementation(() => {});
+    process.env.LLM_PROVIDER = "deepseek";
+    process.env.DEEPSEEK_API_KEY = "test-key";
+    client.setGenerateJsonForValidation(async () => ({ value: "from-llm" }));
+
+    const result = await client.generateValidatedJson({
+      schema: z.object({ value: z.string() }),
+      prompt: "Return JSON.",
+      task: "article_optimizer",
+    });
+
+    expect(result).toEqual({ value: "from-llm" });
+    expect(infoSpy).toHaveBeenCalledWith(
+      "[llm:validated] task=article_optimizer ok=true",
+    );
+  });
+
+  it("logs validation failure with a compact Zod summary", async () => {
+    const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+    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.",
+      task: "fact_extractor",
+    });
+
+    expect(result).toBeNull();
+    expect(warnSpy).toHaveBeenCalledWith(
+      expect.stringContaining("[llm:validated] task=fact_extractor ok=false"),
+    );
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("value"));
+  });
+});
+
+describe("generateJson logging", () => {
+  const originalProvider = process.env.LLM_PROVIDER;
+  const originalDeepSeekKey = process.env.DEEPSEEK_API_KEY;
+
+  afterEach(() => {
+    process.env.LLM_PROVIDER = originalProvider;
+    process.env.DEEPSEEK_API_KEY = originalDeepSeekKey;
+    client.setChatCompletionForTesting(null);
+    vi.restoreAllMocks();
+  });
+
+  it("logs provider, model, task, duration, and truncated raw response", async () => {
+    const infoSpy = vi.spyOn(console, "info").mockImplementation(() => {});
+    process.env.LLM_PROVIDER = "deepseek";
+    process.env.DEEPSEEK_API_KEY = "test-key";
+    const longContent = `{"value":"${"x".repeat(4100)}"}`;
+    client.setChatCompletionForTesting(async () => ({
+      choices: [{ message: { content: longContent } }],
+    }));
+
+    const result = await client.generateJson<{ value: string }>({
+      prompt: "Return JSON.",
+      task: "article_optimizer",
+    });
+
+    expect(result.value).toHaveLength(4100);
+    expect(infoSpy).toHaveBeenCalledWith(
+      "[llm:start] provider=deepseek model=deepseek-v4-pro task=article_optimizer",
+    );
+    const responseLog = infoSpy.mock.calls
+      .map((call) => call[0])
+      .find((line) => line.startsWith("[llm:response]"));
+    expect(responseLog).toContain("task=article_optimizer");
+    expect(responseLog).toContain("duration_ms=");
+    expect(responseLog).toContain("raw=");
+    expect(responseLog?.length).toBeLessThan(4200);
+  });
+
+  it("logs provider errors without leaking API keys", async () => {
+    const infoSpy = vi.spyOn(console, "info").mockImplementation(() => {});
+    const errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    process.env.LLM_PROVIDER = "deepseek";
+    process.env.DEEPSEEK_API_KEY = "super-secret-key";
+    client.setChatCompletionForTesting(async () => {
+      throw new Error("upstream unavailable");
+    });
+
+    await expect(
+      client.generateJson({
+        prompt: "Return JSON.",
+        task: "quality_inspector",
+      }),
+    ).rejects.toThrow("LLM provider error: upstream unavailable");
+
+    expect(infoSpy).toHaveBeenCalledWith(
+      "[llm:start] provider=deepseek model=deepseek-v4-pro task=quality_inspector",
+    );
+    const errorLog = errorSpy.mock.calls.map((call) => call[0]).join("\n");
+    expect(errorLog).toContain("[llm:error] task=quality_inspector");
+    expect(errorLog).not.toContain("super-secret-key");
+  });
 });