fix(delegate): inherit subagent endpoint from parent active client

When parent_agent.base_url still carries a stale OpenRouter URL but the
live OpenAI client already points at local Ollama, subagents were routing
API calls to OpenRouter and failing with HTTP 401. Prefer _client_kwargs
and the mounted client base_url when they disagree with the surface field.

tools/delegate_tool.py

@@ -988,6 +988,44 @@ def _build_child_progress_callback(
     return _callback
 
 
+def _normalized_runtime_url(value: Any) -> str:
+    return str(value or "").strip().rstrip("/")
+
+
+def _inherit_parent_base_url(parent_agent, fallback_base_url: Optional[str]) -> Optional[str]:
+    """Return the base URL the parent is actually calling, not a stale attribute.
+
+    ``parent_agent.base_url`` can still carry a leftover OpenRouter URL from an
+    old config while the live OpenAI client in ``_client_kwargs`` already points
+    at local Ollama. Subagents must inherit the active endpoint or they 401
+    against OpenRouter with a dummy/local key.
+    """
+    surface_url = _normalized_runtime_url(fallback_base_url)
+    client_kwargs = getattr(parent_agent, "_client_kwargs", None)
+    if isinstance(client_kwargs, dict):
+        kwargs_url = _normalized_runtime_url(client_kwargs.get("base_url"))
+        if (
+            kwargs_url
+            and kwargs_url != surface_url
+            and kwargs_url.startswith(("http://", "https://"))
+        ):
+            return kwargs_url
+
+    client = getattr(parent_agent, "client", None)
+    if client is not None:
+        live_raw = getattr(client, "base_url", "")
+        if isinstance(live_raw, str):
+            live_url = _normalized_runtime_url(live_raw)
+            if (
+                live_url
+                and live_url != surface_url
+                and live_url.startswith(("http://", "https://"))
+            ):
+                return live_url
+
+    return fallback_base_url or None
+
+
 def _build_child_agent(
     task_index: int,
     goal: str,
@@ -1144,6 +1182,8 @@ def _build_child_agent(
     effective_model = model or parent_agent.model
     effective_provider = override_provider or getattr(parent_agent, "provider", None)
     effective_base_url = override_base_url or parent_agent.base_url
+    if not override_base_url:
+        effective_base_url = _inherit_parent_base_url(parent_agent, effective_base_url)
     effective_api_key = override_api_key or parent_api_key
     # Bug #20558 / PR #20563: api_mode must NOT be inherited when the child uses a
     # different provider than the parent — each provider has its own API surface