diff --git a/hermes_cli/doctor.py b/hermes_cli/doctor.py
index 9d3b6e3c01a..07aaa2e38bc 100644
--- a/hermes_cli/doctor.py
+++ b/hermes_cli/doctor.py
@@ -1474,6 +1474,15 @@ def run_doctor(args):
             }
             if base_url_host_matches(base, "api.kimi.com"):
                 headers["User-Agent"] = "claude-code/0.1.0"
+            # Google's Generative Language API (generativelanguage.googleapis.com)
+            # rejects ``Authorization: Bearer <api-key>`` with 401
+            # ``ACCESS_TOKEN_TYPE_UNSUPPORTED`` — that header is reserved for
+            # OAuth 2 access tokens, not plain API keys. Plain keys use
+            # ``x-goog-api-key`` (or ``?key=``). Without this, a perfectly valid
+            # GOOGLE_API_KEY/GEMINI_API_KEY always shows red in ``hermes doctor``.
+            if url and base_url_host_matches(url, "generativelanguage.googleapis.com"):
+                headers.pop("Authorization", None)
+                headers["x-goog-api-key"] = key
             r = httpx.get(url, headers=headers, timeout=10)
             if (
                 pname == "Alibaba/DashScope"