diff --git a/agent/auxiliary_client.py b/agent/auxiliary_client.py
index 1884369c28b..23d29493a84 100644
--- a/agent/auxiliary_client.py
+++ b/agent/auxiliary_client.py
@@ -4307,6 +4307,8 @@ def resolve_provider_client(
 
     # ── Custom endpoint (OPENAI_BASE_URL + OPENAI_API_KEY) ───────────
     if provider == "custom":
+        custom_base = ""
+        custom_key = ""
         if explicit_base_url:
             custom_base = _to_openai_base_url(explicit_base_url).strip()
             custom_key = (
@@ -4321,6 +4323,19 @@ def resolve_provider_client(
                     "but base_url is empty"
                 )
                 return None, None
+        elif main_runtime:
+            # When main_runtime carries a concrete base_url + api_key for a
+            # named custom provider (custom:<name>), use it directly instead
+            # of re-resolving from the bare "custom" provider name.
+            # Re-resolution loses the provider name and falls back to
+            # OpenRouter or a wrong API-key provider — the main agent already
+            # solved this, we just need to reuse its answer. (#45472)
+            _main_base = str(main_runtime.get("base_url") or "").strip().rstrip("/")
+            _main_key = str(main_runtime.get("api_key") or "").strip()
+            if _main_base and _main_key:
+                custom_base = _main_base
+                custom_key = _main_key
+        if custom_base and custom_key:
             final_model = _normalize_resolved_model(
                 model or (main_runtime.get("model") if main_runtime else None) or "gpt-4o-mini",
                 provider,
@@ -4357,49 +4372,6 @@ def resolve_provider_client(
                     else (client, final_model))
         # Try custom first, then API-key providers (Codex excluded here:
         # falling through to Codex with no model is a stale-constant trap).
-        #
-        # When main_runtime carries a concrete base_url + api_key for a
-        # named custom provider (custom:<name>), use it directly instead of
-        # re-resolving from the bare "custom" provider name.  Re-resolution
-        # loses the provider name and falls back to OpenRouter or a wrong
-        # API-key provider — the main agent already solved this, we just
-        # need to reuse its answer. (#45472)
-        if main_runtime:
-            main_base = str(main_runtime.get("base_url") or "").strip().rstrip("/")
-            main_key = str(main_runtime.get("api_key") or "").strip()
-            if main_base and main_key:
-                final_model = _normalize_resolved_model(
-                    model or main_runtime.get("model") or "gpt-4o-mini",
-                    provider,
-                )
-                extra = {}
-                _clean_base, _dq = _extract_url_query_params(main_base)
-                if _dq:
-                    extra["default_query"] = _dq
-                if base_url_host_matches(main_base, "api.kimi.com"):
-                    extra["default_headers"] = {"User-Agent": "claude-code/0.1.0"}
-                elif base_url_host_matches(main_base, "api.githubcopilot.com"):
-                    from hermes_cli.copilot_auth import copilot_request_headers
-                    extra["default_headers"] = copilot_request_headers(
-                        is_agent_turn=True, is_vision=is_vision
-                    )
-                elif base_url_host_matches(main_base, "integrate.api.nvidia.com"):
-                    extra["default_headers"] = build_nvidia_nim_headers(main_base)
-                else:
-                    try:
-                        from providers import get_provider_profile as _gpf_main
-                        _ph_main = _gpf_main(provider)
-                        if _ph_main and _ph_main.default_headers:
-                            extra["default_headers"] = dict(_ph_main.default_headers)
-                    except Exception:
-                        pass
-                _merged_main = _apply_user_default_headers(extra.get("default_headers"))
-                if _merged_main:
-                    extra["default_headers"] = _merged_main
-                client = OpenAI(api_key=main_key, base_url=_clean_base, **extra)
-                client = _wrap_if_needed(client, final_model, main_base, main_key)
-                return (_to_async_client(client, final_model, is_vision=is_vision) if async_mode
-                        else (client, final_model))
         for try_fn in (_try_custom_endpoint, _resolve_api_key_provider):
             client, default = try_fn()
             if client is not None: