fix: build errors and Copilot round 4 feedback

1. Fix NO_TOOLS type: Object.freeze produces readonly array incompatible
   with ToolUnion[]. Use Readonly<Pick<>> instead; spread in requestConfig
   already creates a fresh mutable copy per call.

2. Fix test missing required 'model' field in ContentGeneratorConfig.

3. Track firstResponseId/firstModelVersion in loggingStreamWrapper so
   _logApiResponse/_logApiError have accurate values even when full
   response collection is skipped for internal prompts.

4. Strengthen OpenAI logger test assertion: assert OpenAILogger was
   constructed (not guarded by if), then assert logInteraction was
   not called.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: wenshao

packages/core/src/core/loggingContentGenerator/loggingContentGenerator.test.ts

@@ -496,6 +496,7 @@ describe('LoggingContentGenerator', () => {
       } as unknown as ContentGenerator;
 
       const gen = new LoggingContentGenerator(mockWrapped, createConfig(), {
+        model: 'test-model',
         enableOpenAILogging: true,
         openAILoggingDir: '/tmp/test-logs',
       });
@@ -511,13 +512,12 @@ describe('LoggingContentGenerator', () => {
       expect(logApiRequest).not.toHaveBeenCalled();
       // logApiResponse SHOULD be called (for /stats token tracking)
       expect(logApiResponse).toHaveBeenCalled();
-      // OpenAI logger should NOT be called
+      // OpenAI logger should be constructed, but no interaction should be logged
+      expect(OpenAILogger).toHaveBeenCalled();
       const loggerInstance = (
         OpenAILogger as unknown as ReturnType<typeof vi.fn>
       ).mock.results[0]?.value;
-      if (loggerInstance) {
-        expect(loggerInstance.logInteraction).not.toHaveBeenCalled();
-      }
+      expect(loggerInstance.logInteraction).not.toHaveBeenCalled();
     },
   );
 });

packages/core/src/core/loggingContentGenerator/loggingContentGenerator.ts

@@ -229,9 +229,19 @@ export class LoggingContentGenerator implements ContentGenerator {
     // skip collecting full responses to avoid unnecessary memory overhead.
     const responses: GenerateContentResponse[] = [];
 
+    // Track first-seen IDs so _logApiResponse/_logApiError have accurate
+    // values even when we skip collecting full responses for internal prompts.
+    let firstResponseId = '';
+    let firstModelVersion = '';
     let lastUsageMetadata: GenerateContentResponseUsageMetadata | undefined;
     try {
       for await (const response of stream) {
+        if (!firstResponseId && response.responseId) {
+          firstResponseId = response.responseId;
+        }
+        if (!firstModelVersion && response.modelVersion) {
+          firstModelVersion = response.modelVersion;
+        }
         if (!isInternal) {
           responses.push(response);
         }
@@ -243,9 +253,9 @@ export class LoggingContentGenerator implements ContentGenerator {
       // Only log successful API response if no error occurred
       const durationMs = Date.now() - startTime;
       this._logApiResponse(
-        responses[0]?.responseId ?? '',
+        firstResponseId,
         durationMs,
-        responses[0]?.modelVersion || model,
+        firstModelVersion || model,
         userPromptId,
         lastUsageMetadata,
       );
@@ -257,10 +267,10 @@ export class LoggingContentGenerator implements ContentGenerator {
     } catch (error) {
       const durationMs = Date.now() - startTime;
       this._logApiError(
-        responses[0]?.responseId ?? '',
+        firstResponseId,
         durationMs,
         error,
-        responses[0]?.modelVersion || model,
+        firstModelVersion || model,
         userPromptId,
       );
       if (!isInternal) {

packages/core/src/followup/forkedQuery.ts

@@ -26,9 +26,7 @@ import { GeminiChat, StreamEventType } from '../core/geminiChat.js';
 import type { Config } from '../config/config.js';
 
 /** Per-request config that strips tools so the model never produces function calls. */
-const NO_TOOLS: GenerateContentConfig = Object.freeze({
-  tools: Object.freeze([]),
-});
+const NO_TOOLS: Readonly<Pick<GenerateContentConfig, 'tools'>> = { tools: [] };
 
 /**
  * Snapshot of the main conversation's cache-critical parameters.