Add createStreamFn for CORS proxy support

- createStreamFn(proxyUrl?) returns a sync streamFn that applies proxy
- Example reads proxy settings once when creating Agent
- Matches old ProviderTransport behavior

packages/web-ui/example/src/main.ts

@@ -8,6 +8,7 @@ import {
 	ChatPanel,
 	CustomProvidersStore,
 	createJavaScriptReplTool,
+	createStreamFn,
 	IndexedDBStorageBackend,
 	// PersistentStorageDialog, // TODO: Fix - currently broken
 	ProviderKeysStore,
@@ -160,6 +161,10 @@ const createAgent = async (initialState?: Partial<AgentState>) => {
 		agentUnsubscribe();
 	}
 
+	// Read proxy settings for streamFn
+	const proxyEnabled = await storage.settings.get<boolean>("proxy.enabled");
+	const proxyUrl = proxyEnabled ? (await storage.settings.get<string>("proxy.url")) || undefined : undefined;
+
 	agent = new Agent({
 		initialState: initialState || {
 			systemPrompt: `You are a helpful AI assistant with access to various tools.
@@ -181,6 +186,8 @@ Feel free to use these tools when needed to provide accurate and helpful respons
 			const key = await storage.providerKeys.get(provider);
 			return key ?? undefined;
 		},
+		// Use streamFn with CORS proxy support
+		streamFn: createStreamFn(proxyUrl),
 	});
 
 	agentUnsubscribe = agent.subscribe((event: any) => {

packages/web-ui/src/index.ts

@@ -112,3 +112,4 @@ export { loadAttachment } from "./utils/attachment-utils.js";
 export { clearAuthToken, getAuthToken } from "./utils/auth-token.js";
 export { formatCost, formatModelCost, formatTokenCount, formatUsage } from "./utils/format.js";
 export { i18n, setLanguage, translations } from "./utils/i18n.js";
+export { applyProxyIfNeeded, createStreamFn, isCorsError, shouldUseProxyForProvider } from "./utils/proxy-utils.js";

packages/web-ui/src/utils/proxy-utils.ts

@@ -1,4 +1,5 @@
-import type { Api, Model } from "@mariozechner/pi-ai";
+import type { Api, Context, Model, SimpleStreamOptions } from "@mariozechner/pi-ai";
+import { streamSimple } from "@mariozechner/pi-ai";
 
 /**
  * Centralized proxy decision logic.
@@ -110,3 +111,21 @@ export function isCorsError(error: unknown): boolean {
 
 	return false;
 }
+
+/**
+ * Create a streamFn that applies CORS proxy when needed.
+ *
+ * @param proxyUrl - CORS proxy URL, or undefined to disable
+ * @returns A streamFn compatible with Agent's streamFn option
+ */
+export function createStreamFn(proxyUrl?: string) {
+	return (model: Model<any>, context: Context, options?: SimpleStreamOptions) => {
+		const apiKey = options?.apiKey;
+		if (!apiKey || !proxyUrl) {
+			return streamSimple(model, context, options);
+		}
+
+		const proxiedModel = applyProxyIfNeeded(model, apiKey, proxyUrl);
+		return streamSimple(proxiedModel, context, options);
+	};
+}