fix(qa): preserve Code Mode reads in model-switch mock (#122935)

extensions/qa-lab/src/providers/mock-openai/mock-openai-events.ts

@@ -1,11 +1,7 @@
 // QA Lab mock provider output event builders.
 
 import type { StreamEvent } from "./mock-openai-contracts.js";
-import {
-  readTargetFromPrompt,
-  buildMockFunctionCall,
-  buildToolCallEventsWithArgs,
-} from "./mock-openai-tooling.js";
+import { buildMockFunctionCall } from "./mock-openai-tooling.js";
 
 export function buildFailedResponseEvents(): StreamEvent[] {
   const responseId = `resp_qa_failed_${Date.now()}`;
@@ -55,11 +51,6 @@ export function buildPartialFailureEvents(partialText: string): StreamEvent[] {
   ];
 }
 
-export function buildToolCallEvents(prompt: string): StreamEvent[] {
-  const targetPath = readTargetFromPrompt(prompt);
-  return buildToolCallEventsWithArgs("read", { path: targetPath });
-}
-
 export function buildReleaseAuditJson() {
   return `${JSON.stringify(
     {

extensions/qa-lab/src/providers/mock-openai/server.test.ts

@@ -6396,6 +6396,49 @@ Update and merge these partial structured summaries.`,
     expect(await response.text()).toContain('"name":"read"');
   });
 
+  it("routes the initial model-switch read through Anthropic guest Code Mode", async () => {
+    const server = await startMockServer();
+    const body = (await expectAnthropicMessagesJson(server, {
+      tools: [
+        {
+          name: "exec",
+          input_schema: {
+            type: "object",
+            properties: { code: { type: "string" } },
+            required: ["code"],
+          },
+        },
+        {
+          name: "wait",
+          input_schema: {
+            type: "object",
+            properties: { runId: { type: "string" } },
+            required: ["runId"],
+          },
+        },
+      ],
+      messages: [
+        makeAnthropicUserText(
+          "Read repo/qa/scenarios/index.yaml and summarize the QA scenario pack mission in one clause before any model switch.",
+        ),
+      ],
+    })) as {
+      stop_reason: string;
+      content: Array<Record<string, unknown>>;
+    };
+
+    expect(body.stop_reason).toBe("tool_use");
+    expect(body.content.find((block) => block.type === "tool_use")?.name).toBe("exec");
+
+    const debug = requireRecord(
+      await getJson(server, "/debug/last-request"),
+      "model switch Code Mode debug request",
+    );
+    expect(debug.plannedToolName).toBe("read");
+    expect(debug.plannedWireToolName).toBe("exec");
+    expect(debug.plannedToolArgs).toEqual({ path: "repo/qa/scenarios/index.yaml" });
+  });
+
   it("returns continuity language after the model-switch reread completes", async () => {
     const server = await startMockServer();
 

extensions/qa-lab/src/providers/mock-openai/server.ts

@@ -134,7 +134,6 @@ import {
   isHeartbeatPrompt,
 } from "./mock-openai-directives.js";
 import {
-  buildToolCallEvents,
   buildReleaseAuditJson,
   buildReleaseHandoffMarkdown,
   extractPlannedToolName,
@@ -2363,7 +2362,7 @@ async function buildResponsesPayload(
     });
   }
   if (!hasCompletedToolOutput && /\b(read|inspect|repo|docs|scenario|kickoff)\b/i.test(prompt)) {
-    return buildToolCallEvents(prompt);
+    return buildToolCallEventsWithArgs("read", { path: readTargetFromPrompt(prompt) });
   }
   if (/visible skill marker/i.test(prompt) && !hasCompletedToolOutput) {
     return buildAssistantEvents("VISIBLE-SKILL-OK");