fix: keep CLI prepare credentials private

src/agents/cli-runner/prepare.test.ts

@@ -412,6 +412,70 @@ describe("shouldSkipLocalCliCredentialEpoch", () => {
     }
   });
 
+  it("does not expose auth profile credentials to non-Gemini CLI prepare hooks", async () => {
+    const { dir, sessionFile } = createSessionFile();
+    const agentDir = path.join(dir, "agents", "main", "agent");
+    const authProfileId = "test-cli:secret";
+    const prepareExecution = vi.fn(async () => undefined);
+    fs.mkdirSync(agentDir, { recursive: true });
+    saveAuthProfileStore(
+      {
+        version: 1,
+        profiles: {
+          [authProfileId]: {
+            type: "api_key",
+            provider: "test-cli",
+            key: "secret-key",
+          },
+        },
+      },
+      agentDir,
+    );
+    cliBackendsTesting.setDepsForTest({
+      resolvePluginSetupCliBackend: () => undefined,
+      resolveRuntimeCliBackends: () => [
+        {
+          id: "test-cli",
+          pluginId: "test-plugin",
+          bundleMcp: false,
+          prepareExecution,
+          config: {
+            command: "test-cli",
+            args: ["--prompt", "{prompt}"],
+            output: "json",
+            input: "arg",
+            sessionMode: "existing",
+          },
+        },
+      ],
+    });
+
+    try {
+      await prepareCliRunContext({
+        sessionId: "session-test",
+        sessionKey: "agent:main:main",
+        sessionFile,
+        workspaceDir: dir,
+        prompt: "latest ask",
+        provider: "test-cli",
+        model: "test-model",
+        timeoutMs: 1_000,
+        runId: "run-test-non-gemini-credential-boundary",
+        authProfileId,
+        config: {},
+      });
+
+      expect(prepareExecution).toHaveBeenCalledWith(
+        expect.objectContaining({
+          authProfileId,
+        }),
+      );
+      expect(prepareExecution.mock.calls[0]?.[0]).not.toHaveProperty("authCredential");
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
   it("prepares side questions without agent-turn context, tools, hooks, or reusable sessions", async () => {
     const { dir, sessionFile } = createSessionFile();
     appendTranscriptEntry(sessionFile, {

src/agents/cli-runner/prepare.ts

@@ -463,20 +463,28 @@ export async function prepareCliRunContext(
       : undefined,
     warn: (message) => cliBackendLog.warn(message),
   });
-  const preparedExecution = await backendResolved.prepareExecution?.({
+  const prepareExecutionContext = {
     config: params.config,
     workspaceDir,
     agentDir,
     provider: params.provider,
     modelId,
     authProfileId: effectiveAuthProfileId,
-    // Private bridge for bundled Gemini CLI. This is intentionally not part
-    // of the public Plugin SDK until a credential-forwarding contract exists.
-    authCredential,
     executionMode,
-  } as Parameters<NonNullable<typeof backendResolved.prepareExecution>>[0] & {
-    authCredential?: AuthProfileCredential;
-  });
+  } as Parameters<NonNullable<typeof backendResolved.prepareExecution>>[0];
+  const preparedExecution = await backendResolved.prepareExecution?.(
+    (backendResolved.id === "google-gemini-cli"
+      ? {
+          ...prepareExecutionContext,
+          // Private bridge for bundled Gemini CLI. This is intentionally not
+          // part of the public Plugin SDK until a credential-forwarding
+          // contract exists.
+          authCredential,
+        }
+      : prepareExecutionContext) as typeof prepareExecutionContext & {
+      authCredential?: AuthProfileCredential;
+    },
+  );
   const skipLocalCredentialEpoch = shouldSkipLocalCliCredentialEpoch({
     authEpochMode: backendResolved.authEpochMode,
     authProfileId: effectiveAuthProfileId,