--- agent/azure_identity_adapter.py.orig	2026-09-24 10:08:47 UTC
+++ agent/azure_identity_adapter.py
@@ -304,14 +304,21 @@ def _strip_auth_headers(request: Any) -> None:
         request.headers.pop(header_name, None)
 
 
-def build_bearer_http_client(token_provider: Callable[[], str], **httpx_kwargs: Any) -> Any:
+def build_bearer_http_client(token_provider: Callable[[], str], *, httpx_mod: Any = None,
+                             **httpx_kwargs: Any) -> Any:
     """``httpx.Client`` minting a fresh Entra bearer JWT per outbound request. The Anthropic SDK computes
     ``Authorization`` once at construction, so per-request refresh needs a ``request`` hook: mint (cheap —
     azure-identity caches), strip pre-set auth headers, set ``Authorization: Bearer``. ``httpx_kwargs`` are
-    forwarded verbatim (``timeout``, ``transport``...)."""
+    forwarded verbatim (``timeout``, ``transport``...).
+
+    ``httpx_mod`` lets the caller pass the httpx flavour its SDK is built against (anthropic 1.x
+    vendors ``httpx2``); the client object must come from that same module or the SDK rejects it.
+    Defaults to plain ``httpx``."""
     if not is_token_provider(token_provider):
         raise ValueError("build_bearer_http_client requires a zero-arg callable token provider")
-    import httpx
+    if httpx_mod is None:
+        import httpx as httpx_mod  # type: ignore[no-redef]
+    httpx = httpx_mod
 
     def _inject_bearer(request: "httpx.Request") -> None:
         try: