fix(browser): prevent fetch proxy fallback

Author: MagMueller

packages/bcode-browser/src/fetch-use.ts

@@ -1,8 +1,8 @@
 // FetchUse — Effect service that proxies HTTP through Browser Use's fetch-use
 // cloud (Chrome JA4, HTTP/2 header order, session cookies). Decisions §3.3.
-// `enabled` is true when either a direct Browser Use API key or a scoped proxy
-// token is set; webfetch.ts combines this with the user's
-// `experimental.fetch_use` opencode.json setting.
+// `enabled` selects this route when direct credentials are complete or any
+// scoped-proxy setting is present. Partial proxy config stays selected and
+// errors instead of silently falling back to native HTTP.
 
 import { Context, Effect, Layer } from "effect"
 import { HttpClient, HttpClientRequest } from "effect/unstable/http"
@@ -37,7 +37,7 @@ export const makeLayer = (options: { proxyUrl: string; apiKey: string; proxyToke
       const proxyEnabled = options.proxyUrl.length > 0 && options.proxyToken.length > 0
       const directEnabled = !hasProxySetting && options.apiKey.length > 0
       return Service.of({
-        enabled: proxyEnabled || directEnabled,
+        enabled: hasProxySetting || directEnabled,
         fetch: (url, { timeoutMs }) =>
           Effect.gen(function* () {
             if (!proxyEnabled && !directEnabled) {

packages/bcode-browser/test/fetch-use.test.ts

@@ -12,15 +12,13 @@ import { FetchHttpClient } from "effect/unstable/http"
 import { FetchUse } from "../src/fetch-use"
 
 const haveProxySetting = !!process.env.BROWSER_USE_FETCH_URL || !!process.env.BROWSER_USE_FETCH_TOKEN
-const haveCredential =
-  (!!process.env.BROWSER_USE_FETCH_URL && !!process.env.BROWSER_USE_FETCH_TOKEN) ||
-  (!haveProxySetting && !!process.env.BROWSER_USE_API_KEY)
+const fetchUseSelected = haveProxySetting || !!process.env.BROWSER_USE_API_KEY
 
-test("layer constructs and exposes `enabled` reflecting env", async () => {
+test("layer selects fetch-use for direct or scoped-proxy configuration", async () => {
   const enabled = await Effect.gen(function* () {
     return (yield* FetchUse.Service).enabled
   }).pipe(Effect.provide(FetchUse.layer.pipe(Layer.provide(FetchHttpClient.layer))), Effect.runPromise)
-  expect(enabled).toBe(haveCredential)
+  expect(enabled).toBe(fetchUseSelected)
 })
 
 test.skipIf(!process.env.BROWSER_USE_API_KEY)("live: fetches httpbin and returns body + content-type", async () => {
@@ -79,7 +77,8 @@ test.each([
 ])("partial proxy configuration fails closed", async (options) => {
   const result = await Effect.gen(function* () {
     const service = yield* FetchUse.Service
-    expect(service.enabled).toBe(false)
+    // Keep this route selected so webfetch cannot silently use native HTTP.
+    expect(service.enabled).toBe(true)
     return yield* Effect.flip(service.fetch("https://example.com", { timeoutMs: 1_000 }))
   }).pipe(
     Effect.provide(FetchUse.makeLayer(options).pipe(Layer.provide(FetchHttpClient.layer))),