fix(ai): forward google vertex base url

closes #3619

packages/ai/CHANGELOG.md

@@ -5,9 +5,11 @@
 ### Added
 
 - Added GPT-5.5 to OpenAI Codex model generation.
+- Added `findEnvKeys()` so callers can identify configured provider API-key environment variables without exposing credential values while preserving `getEnvApiKey()` as the credential-value API.
 
 ### Fixed
 
+- Fixed `google-vertex` to forward custom `model.baseUrl` values to `@google/genai`, enabling Vertex proxy and gateway endpoints ([#3619](https://github.com/badlogic/pi-mono/issues/3619))
 - Fixed OpenAI-compatible completion usage parsing to stop double-counting reasoning tokens already included in `completion_tokens` ([#3581](https://github.com/badlogic/pi-mono/issues/3581))
 - Fixed long cache retention compatibility by adding `compat.supportsLongCacheRetention`, allowing Anthropic Messages and OpenAI-compatible proxies to explicitly disable long-retention fields while enabling long retention by default when requested ([#3543](https://github.com/badlogic/pi-mono/issues/3543))
 - Fixed `openai-responses` compatibility by adding `compat.sendSessionIdHeader: false`, allowing strict OpenAI-compatible proxies to omit the underscore-containing `session_id` header while still sending other session-affinity headers ([#3579](https://github.com/badlogic/pi-mono/issues/3579))
@@ -16,6 +18,7 @@
 - Fixed `openai-completions` streamed tool-call assembly to coalesce deltas by stable tool index when OpenAI-compatible gateways mutate tool call IDs mid-stream, preventing malformed Kimi K2.6/OpenCode tool streams from splitting one call into multiple bogus tool calls ([#3576](https://github.com/badlogic/pi-mono/issues/3576))
 - Fixed `packages/ai` E2E coverage to use currently supported OpenAI Responses and OpenAI Codex models, and updated the Bedrock adaptive-thinking payload expectation to match the current `display: "summarized"` shape.
 - Fixed built-in `kimi-coding` model generation to attach `User-Agent: KimiCLI/1.5` to all generated Kimi models, overriding the Anthropic SDK default UA so direct Kimi Coding requests use the provider's expected client identity ([#3586](https://github.com/badlogic/pi-mono/issues/3586))
+- Fixed GPT-5.5 Codex capability handling to clamp unsupported minimal reasoning to `low` and apply the model's 2.5x priority service-tier pricing multiplier ([#3618](https://github.com/badlogic/pi-mono/pull/3618) by [@markusylisiurunen](https://github.com/markusylisiurunen))
 
 ## [0.69.0] - 2026-04-22
 

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

@@ -2,6 +2,8 @@ import {
 	type GenerateContentConfig,
 	type GenerateContentParameters,
 	GoogleGenAI,
+	type HttpOptions,
+	ResourceScope,
 	type ThinkingConfig,
 	ThinkingLevel,
 } from "@google/genai";
@@ -331,20 +333,12 @@ function createClient(
 	location: string,
 	optionsHeaders?: Record<string, string>,
 ): GoogleGenAI {
-	const httpOptions: { headers?: Record<string, string> } = {};
-
-	if (model.headers || optionsHeaders) {
-		httpOptions.headers = { ...model.headers, ...optionsHeaders };
-	}
-
-	const hasHttpOptions = Object.values(httpOptions).some(Boolean);
-
 	return new GoogleGenAI({
 		vertexai: true,
 		project,
 		location,
 		apiVersion: API_VERSION,
-		httpOptions: hasHttpOptions ? httpOptions : undefined,
+		httpOptions: buildHttpOptions(model, optionsHeaders),
 	});
 }
 
@@ -353,20 +347,50 @@ function createClientWithApiKey(
 	apiKey: string,
 	optionsHeaders?: Record<string, string>,
 ): GoogleGenAI {
-	const httpOptions: { headers?: Record<string, string> } = {};
+	return new GoogleGenAI({
+		vertexai: true,
+		apiKey,
+		apiVersion: API_VERSION,
+		httpOptions: buildHttpOptions(model, optionsHeaders),
+	});
+}
+
+function buildHttpOptions(
+	model: Model<"google-vertex">,
+	optionsHeaders?: Record<string, string>,
+): HttpOptions | undefined {
+	const httpOptions: HttpOptions = {};
+	const baseUrl = resolveCustomBaseUrl(model.baseUrl);
+	if (baseUrl) {
+		httpOptions.baseUrl = baseUrl;
+		httpOptions.baseUrlResourceScope = ResourceScope.COLLECTION;
+		if (baseUrlIncludesApiVersion(baseUrl)) {
+			httpOptions.apiVersion = "";
+		}
+	}
 
 	if (model.headers || optionsHeaders) {
 		httpOptions.headers = { ...model.headers, ...optionsHeaders };
 	}
 
-	const hasHttpOptions = Object.values(httpOptions).some(Boolean);
+	return Object.keys(httpOptions).length > 0 ? httpOptions : undefined;
+}
 
-	return new GoogleGenAI({
-		vertexai: true,
-		apiKey,
-		apiVersion: API_VERSION,
-		httpOptions: hasHttpOptions ? httpOptions : undefined,
-	});
+function resolveCustomBaseUrl(baseUrl: string): string | undefined {
+	const trimmed = baseUrl.trim();
+	if (!trimmed || trimmed.includes("{location}")) {
+		return undefined;
+	}
+	return trimmed;
+}
+
+function baseUrlIncludesApiVersion(baseUrl: string): boolean {
+	try {
+		const url = new URL(baseUrl);
+		return url.pathname.split("/").some((part) => /^v\d+(?:beta\d*)?$/.test(part));
+	} catch {
+		return /(?:^|\/)v\d+(?:beta\d*)?(?:\/|$)/.test(baseUrl);
+	}
 }
 
 function resolveApiKey(options?: GoogleVertexOptions): string | undefined {

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

@@ -32,6 +32,9 @@ vi.mock("@google/genai", () => {
 
 	return {
 		GoogleGenAI,
+		ResourceScope: {
+			COLLECTION: "COLLECTION",
+		},
 		ThinkingLevel: {
 			THINKING_LEVEL_UNSPECIFIED: "THINKING_LEVEL_UNSPECIFIED",
 			MINIMAL: "MINIMAL",
@@ -44,7 +47,7 @@ vi.mock("@google/genai", () => {
 
 import { getModel } from "../src/models.js";
 import { streamGoogleVertex } from "../src/providers/google-vertex.js";
-import type { Context } from "../src/types.js";
+import type { Context, Model } from "../src/types.js";
 
 const model = getModel("google-vertex", "gemini-3-flash-preview");
 const context: Context = {
@@ -141,4 +144,80 @@ describe("google-vertex api key resolution", () => {
 		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("project");
 		expect(googleGenAiMock.constructorCalls[0]).not.toHaveProperty("location");
 	});
+
+	it("does not forward generated Vertex base URL placeholders", async () => {
+		const stream = streamGoogleVertex(model, context, {
+			project: "test-project",
+			location: "us-central1",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]?.httpOptions).toBeUndefined();
+	});
+
+	it("forwards custom baseUrl to the ADC client", async () => {
+		const customModel: Model<"google-vertex"> = { ...model, baseUrl: "https://proxy.example.com" };
+		const stream = streamGoogleVertex(customModel, 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",
+			httpOptions: {
+				baseUrl: "https://proxy.example.com",
+				baseUrlResourceScope: "COLLECTION",
+			},
+		});
+	});
+
+	it("forwards custom baseUrl to the API key client", async () => {
+		const customModel: Model<"google-vertex"> = { ...model, baseUrl: "https://proxy.example.com" };
+		const stream = streamGoogleVertex(customModel, context, {
+			apiKey: "AIzaSyExampleRealisticLookingApiKey123456",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]).toMatchObject({
+			vertexai: true,
+			apiKey: "AIzaSyExampleRealisticLookingApiKey123456",
+			apiVersion: "v1",
+			httpOptions: {
+				baseUrl: "https://proxy.example.com",
+				baseUrlResourceScope: "COLLECTION",
+			},
+		});
+	});
+
+	it("does not append apiVersion when custom baseUrl already includes one", async () => {
+		const customModel: Model<"google-vertex"> = {
+			...model,
+			baseUrl: "https://proxy.example.com/v1/projects/test-project/locations/global",
+		};
+		const stream = streamGoogleVertex(customModel, context, {
+			project: "test-project",
+			location: "us-central1",
+		});
+
+		await stream.result();
+
+		expect(googleGenAiMock.constructorCalls).toHaveLength(1);
+		expect(googleGenAiMock.constructorCalls[0]).toMatchObject({
+			httpOptions: {
+				baseUrl: "https://proxy.example.com/v1/projects/test-project/locations/global",
+				baseUrlResourceScope: "COLLECTION",
+				apiVersion: "",
+			},
+		});
+	});
 });