diff --git a/docs/design/openapi-client-contract.md b/docs/design/openapi-client-contract.md
index 0f3567607..1dd53ede3 100644
--- a/docs/design/openapi-client-contract.md
+++ b/docs/design/openapi-client-contract.md
@@ -130,7 +130,7 @@ global code that is not referenced by any operation is staleness only.
 Provider-readiness/runtime reason registries are separate string registries:
 `READINESS_REASON_CODES` and `REASON_CODES` live at
 `solstone/think/providers/state.py:33-47`, runtime codes live at
-`solstone/think/providers/shared.py:213-225`, and readiness presentation lives
+`solstone/think/providers/shared.py:250-269`, and readiness presentation lives
 at `solstone/convey/provider_readiness.py:83-299`. None of the 14 fragments
 should import those registries.
 
diff --git a/solstone/think/providers/shared.py b/solstone/think/providers/shared.py
index ac0bf4986..a9aed7e88 100644
--- a/solstone/think/providers/shared.py
+++ b/solstone/think/providers/shared.py
@@ -210,6 +210,8 @@ def _chain_has_status_code(exc: BaseException, code: int) -> bool:
 
 
 def mark_cloud_model_request(exc: BaseException) -> None:
+    # OpenHands may classify __cause__/__context__ via _unwrap_provider_exception,
+    # so marking only the caught wrapper would lose transport provenance.
     for item in exception_chain(exc):
         try:
             setattr(item, _CLOUD_MODEL_REQUEST_ATTR, True)
@@ -724,7 +726,6 @@ __all__ = [
     "classify_canned_generate",
     "classify_provider_error",
     "exception_chain",
-    "has_cloud_model_request_mark",
     "is_cloud_model_not_found",
     "mark_cloud_model_request",
     "safe_raw",