diff --git a/agent/anthropic_adapter.py b/agent/anthropic_adapter.py
index e7e1a8acb6..469b0fc9bb 100644
--- a/agent/anthropic_adapter.py
+++ b/agent/anthropic_adapter.py
@@ -471,14 +471,18 @@ def _requires_bearer_auth(base_url: str | None) -> bool:
     """Return True for Anthropic-compatible providers that require Bearer auth.
 
     Some third-party /anthropic endpoints implement Anthropic's Messages API but
-    require Authorization: Bearer *** of Anthropic's native x-api-key header.
-    MiniMax's global and China Anthropic-compatible endpoints follow this pattern.
+    require Authorization: Bearer instead of Anthropic's native x-api-key header.
+    MiniMax's global and China Anthropic-compatible endpoints, and Azure AI
+    Foundry's Anthropic-style endpoint follow this pattern.
     """
     normalized = _normalize_base_url_text(base_url)
     if not normalized:
         return False
     normalized = normalized.rstrip("/").lower()
-    return normalized.startswith(("https://api.minimax.io/anthropic", "https://api.minimaxi.com/anthropic"))
+    return (
+        normalized.startswith(("https://api.minimax.io/anthropic", "https://api.minimaxi.com/anthropic"))
+        or "azure.com" in normalized
+    )
 
 
 def _base_url_needs_context_1m_beta(base_url: str | None) -> bool: