fix(ai): ignore placeholder vertex api keys closes #2335

packages/ai/CHANGELOG.md

@@ -6,6 +6,10 @@
 
 - Added `gpt-5.4-mini` model support for the `openai-codex` provider with Codex pricing metadata and unit coverage.
 
+### Fixed
+
+- Fixed `google-vertex` API key resolution to ignore placeholder auth markers like `<authenticated>` and fall back to ADC instead of sending them as literal API keys ([#2335](https://github.com/badlogic/pi-mono/issues/2335))
+
 ## [0.60.0] - 2026-03-18
 
 ### Fixed

packages/ai/src/providers/google-vertex.ts

@@ -368,7 +368,15 @@ function createClientWithApiKey(
 }
 
 function resolveApiKey(options?: GoogleVertexOptions): string | undefined {
-	return options?.apiKey || process.env.GOOGLE_CLOUD_API_KEY;
+	const apiKey = options?.apiKey?.trim() || process.env.GOOGLE_CLOUD_API_KEY?.trim();
+	if (!apiKey || isPlaceholderApiKey(apiKey)) {
+		return undefined;
+	}
+	return apiKey;
+}
+
+function isPlaceholderApiKey(apiKey: string): boolean {
+	return /^<[^>]+>$/.test(apiKey);
 }
 
 function resolveProject(options?: GoogleVertexOptions): string {

packages/ai/test/google-vertex-api-key-resolution.test.ts

@@ -0,0 +1,125 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+const googleGenAiMock = vi.hoisted(() => ({
+	constructorCalls: [] as Array<Record<string, unknown>>,
+}));
+
+vi.mock("@google/genai", () => {
+	class GoogleGenAI {
+		models = {
+			generateContentStream: async function* () {
+				yield {
+					responseId: "vertex-response-id",
+					candidates: [
+						{
+							content: { parts: [{ text: "ok" }] },
+							finishReason: "STOP",
+						},
+					],
+					usageMetadata: {
+						promptTokenCount: 1,
+						candidatesTokenCount: 1,
+						totalTokenCount: 2,
+					},
+				};
+			},
+		};
+
+		constructor(config: Record<string, unknown>) {
+			googleGenAiMock.constructorCalls.push(config);
+		}
+	}
+
+	return {
+		GoogleGenAI,
+		ThinkingLevel: {
+			THINKING_LEVEL_UNSPECIFIED: "THINKING_LEVEL_UNSPECIFIED",
+			MINIMAL: "MINIMAL",
+			LOW: "LOW",
+			MEDIUM: "MEDIUM",
+			HIGH: "HIGH",
+		},
+	};
+});
+
+import { getModel } from "../src/models.js";
+import { streamGoogleVertex } from "../src/providers/google-vertex.js";
+import type { Context } from "../src/types.js";
+
+const model = getModel("google-vertex", "gemini-3-flash-preview");
+const context: Context = {
+	messages: [{ role: "user", content: "hello", timestamp: Date.now() }],
+};
+
+const originalGoogleCloudApiKey = process.env.GOOGLE_CLOUD_API_KEY;
+
+beforeEach(() => {
+	googleGenAiMock.constructorCalls.length = 0;
+	delete process.env.GOOGLE_CLOUD_API_KEY;
+});
+
+afterEach(() => {
+	if (originalGoogleCloudApiKey === undefined) {
+		delete process.env.GOOGLE_CLOUD_API_KEY;
+	} else {
+		process.env.GOOGLE_CLOUD_API_KEY = originalGoogleCloudApiKey;
+	}
+});
+
+describe("google-vertex api key resolution", () => {
+	it("falls back to ADC when options.apiKey is a placeholder marker", async () => {
+		const stream = streamGoogleVertex(model, context, {
+			apiKey: "<authenticated>",
+			project: "test-project",
+			location: "us-central1",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]).toMatchObject({
+			vertexai: true,
+			project: "test-project",
+			location: "us-central1",
+			apiVersion: "v1",
+		});
+		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("apiKey");
+	});
+
+	it("falls back to ADC when GOOGLE_CLOUD_API_KEY is a placeholder marker", async () => {
+		process.env.GOOGLE_CLOUD_API_KEY = "<authenticated>";
+
+		const stream = streamGoogleVertex(model, context, {
+			project: "test-project",
+			location: "us-central1",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]).toMatchObject({
+			vertexai: true,
+			project: "test-project",
+			location: "us-central1",
+			apiVersion: "v1",
+		});
+		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("apiKey");
+	});
+
+	it("still uses the API key client for real API keys", async () => {
+		const stream = streamGoogleVertex(model, context, {
+			apiKey: "AIzaSyExampleRealisticLookingApiKey123456",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]).toMatchObject({
+			vertexai: true,
+			apiKey: "AIzaSyExampleRealisticLookingApiKey123456",
+			apiVersion: "v1",
+		});
+		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("project");
+		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("location");
+	});
+});