Merge branch 'dev'

copilot/browser.py

@@ -38,6 +38,7 @@ from urllib.parse import parse_qs, urlparse
 from playwright.sync_api import sync_playwright, Error as PlaywrightError
 
 from .auth import DEFAULT_AUTH_FILE, DEFAULT_PROFILE_DIR
+from .useragent import CHROME_UA
 
 COPILOT_URL = "https://copilot.microsoft.com/"
 
@@ -46,17 +47,14 @@ COPILOT_URL = "https://copilot.microsoft.com/"
 # We reach into that frame to click its checkbox — see _click_turnstile.
 _TURNSTILE_IFRAME = "iframe[src*='challenges.cloudflare.com'], iframe[src*='turnstile']"
 
-# A stock desktop Chrome UA used in headless mode. Headless Chromium otherwise
-# advertises "HeadlessChrome/..." in both the request UA header and
-# navigator.userAgent — a blatant bot signal to Cloudflare Turnstile, and a UA
-# that can mismatch the cf_clearance UA-binding the curl_cffi driver relies on
-# (clearance is bound to the UA that earned it). Pinning a normal Chrome UA makes
-# the session look ordinary and keeps the earned clearance reusable. Bump the
-# version occasionally to stay current.
-_STEALTH_UA = (
-    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
-    "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
-)
+# The one UA every browser context advertises — the same string the curl_cffi
+# driver presents (see copilot/useragent.py). Applied to *both* headless and
+# visible launches so clearance earned by either is reusable by the driver:
+# cf_clearance is bound to the earning UA, so they must all match. It also hides
+# the "HeadlessChrome/..." token headless Chromium otherwise leaks (a blatant bot
+# tell). Because CHROME_UA tracks Playwright's bundled Chromium version, the
+# override doesn't contradict the browser's native Sec-CH-UA client hint.
+_STEALTH_UA = CHROME_UA
 
 # Injected into every frame to hide the residual automation tell that survives
 # --disable-blink-features=AutomationControlled in some Chromium builds.
@@ -189,10 +187,11 @@ class BrowserCopilot:
                 # switch; its presence is a cheap bot tell Turnstile reads.
                 ignore_default_args=["--enable-automation"],
             )
-            # Hide the "HeadlessChrome" UA only when actually headless; the visible
-            # window already uses a normal Chrome UA (and that path works today).
-            if self.headless:
-                launch_kwargs["user_agent"] = _STEALTH_UA
+            # Pin the UA on every launch, headless or visible. Both must earn
+            # cf_clearance under the exact string the curl_cffi driver replays;
+            # leaving the visible window on Playwright's native UA would bind the
+            # clearance to a version the driver doesn't present, re-gating chat.
+            launch_kwargs["user_agent"] = _STEALTH_UA
             if self.proxy:
                 launch_kwargs["proxy"] = self._parse_proxy(self.proxy)
             self._context = self._pw.chromium.launch_persistent_context(

copilot/driver.py

@@ -25,6 +25,7 @@ _CURL_SOCKET_BAD = -1
 from .challenges import solve_copilot_challenge, solve_hashcash
 from .models import AbstractProvider, Conversation, ImageResponse, ImageType
 from .protocol import CHAT_WEBSOCKET_URL, CONSENTS_FRAME, SET_OPTIONS_FRAME
+from .useragent import CHROME_CLIENT_HINTS, CHROME_UA, IMPERSONATE_TARGET
 from .utils import drain_json, is_accepted_format, raise_for_status, to_bytes
 
 
@@ -119,7 +120,13 @@ class Copilot(AbstractProvider):
         with Session(
             timeout=timeout,
             proxy=proxy,
-            impersonate="chrome",
+            # Pin the TLS/HTTP2 fingerprint, then override the UA + client hints so
+            # the wire presentation is a fixed Windows Chrome. cf_clearance is bound
+            # to the earning UA; the browsers that earn it present this same string,
+            # so the driver must too — otherwise every turn is gated behind a
+            # Cloudflare Turnstile. See copilot/useragent.py.
+            impersonate=IMPERSONATE_TARGET,
+            headers={"User-Agent": CHROME_UA, **CHROME_CLIENT_HINTS},
             cookies=cookies,
         ) as session:
             # Establish cookies + Cloudflare clearance (anonymous is fine).

copilot/useragent.py

@@ -0,0 +1,48 @@
+"""The single User-Agent the whole bridge presents to Cloudflare.
+
+Cloudflare binds ``cf_clearance`` to the *exact* User-Agent string that earned
+it. The bridge touches that one cookie from three places — the curl_cffi chat
+driver (which *uses* it), the headless refresh, and the interactive login (which
+*earn* it) — so all three must present a byte-identical UA or the clearance is
+distrusted and the chat socket gates every turn behind a Cloudflare Turnstile.
+
+Keeping the string here (imported by both :mod:`copilot.driver` and
+:mod:`copilot.browser`) makes drift impossible.
+
+Why these exact values:
+
+* ``CHROME_UA`` is a real desktop **Windows** Chrome UA. We standardise on the
+  same major version Playwright actually bundles (see the maintenance note), so
+  overriding a launched Chromium's UA to this string does *not* contradict the
+  browser's native ``Sec-CH-UA`` client hint — both say the same version.
+* ``IMPERSONATE_TARGET`` pins curl_cffi to a fixed TLS/HTTP2 fingerprint. Left as
+  the bare ``"chrome"`` alias it tracks curl_cffi's ``DEFAULT_CHROME``, which
+  advances on every upgrade (and ships a *macOS* UA) — a moving target that
+  silently re-breaks the UA match. Pin to the closest stable profile instead; the
+  driver overrides the UA + client hints on top so the wire presentation stays
+  Windows/``CHROME_UA`` regardless of the profile's native UA.
+
+MAINTENANCE: bump ``CHROME_UA``'s major version whenever ``playwright install``
+upgrades the bundled Chromium (check ``chromium.launch().version``). If the
+constant lags the real browser, the browser's native ``Sec-CH-UA`` out-drifts the
+spoofed UA and Turnstile sees the mismatch. One line, one place.
+"""
+
+# Real desktop Windows Chrome. Must match Playwright's bundled Chromium major
+# version (currently 148) so the UA override introduces no client-hint conflict.
+CHROME_UA = (
+    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
+    "(KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36"
+)
+
+# Client hints that must accompany CHROME_UA so the platform/version a server
+# reads from the hints agrees with the UA line. Used by the curl_cffi driver,
+# which otherwise emits the impersonation profile's native (macOS) hints.
+CHROME_CLIENT_HINTS = {
+    "sec-ch-ua-platform": '"Windows"',
+    "sec-ch-ua": '"Google Chrome";v="148", "Chromium";v="148", "Not_A Brand";v="24"',
+}
+
+# Pinned curl_cffi impersonation profile (TLS/HTTP2 fingerprint). Closest stable
+# profile to CHROME_UA's version; the UA itself is overridden on top.
+IMPERSONATE_TARGET = "chrome146"