refactor(agent/relay_runtime,transports): inline single-use _push_session_scope; get_transport rediscovery predicate

agent/relay_runtime.py

@@ -385,27 +385,14 @@ class RelayRuntime:
         with self._execution_consumers_lock:
             return bool(self._execution_consumers)
 
-    def _push_session_scope(
-        self, context: contextvars.Context, *, exit_fallback: bool = False, **push_kwargs: Any
-    ) -> Any:
-        """Push a SESSION_SCOPE Agent scope inside ``context``, bounded by ``_SCOPE_OP_TIMEOUT``.
-        ``exit_fallback``: at interpreter shutdown the executor refuses new futures; push
-        synchronously instead (no agent turn waits at exit)."""
-        args = (self.relay.scope.push, SESSION_SCOPE, self.relay.ScopeType.Agent)
-        try:
-            future = _scope_op_executor().submit(context.run, *args, input={}, **push_kwargs)
-            return future.result(timeout=_SCOPE_OP_TIMEOUT)
-        except RuntimeError:
-            if not exit_fallback:
-                raise
-            return context.run(*args, input={}, **push_kwargs)
-
     def _open_session_scope(
-        self, session: RelaySession, scope_metadata: dict[str, Any], *, resolve_parent: bool, **push_kwargs: Any,
+        self, session: RelaySession, scope_metadata: dict[str, Any], *, resolve_parent: bool,
+        exit_fallback: bool = False, **push_kwargs: Any,
     ) -> None:
-        """Push a fresh session scope for ``session`` and record its handle + context.
-        Subagents parent under their spawning turn/session handle; ``resolve_parent``
-        creates the parent session when its handle is unknown."""
+        """Push a fresh SESSION_SCOPE for ``session`` (bounded by ``_SCOPE_OP_TIMEOUT``); record handle + context.
+        Subagents parent under their spawning turn/session handle; ``resolve_parent`` creates the parent
+        session when its handle is unknown. ``exit_fallback``: at interpreter shutdown the executor refuses
+        new futures; push synchronously instead (no agent turn waits at exit)."""
         parent_handle = None
         if session.parent_session_id:
             with self._sessions_lock:
@@ -416,7 +403,15 @@ class RelayRuntime:
                     parent_handle = parent.handle
             scope_metadata["nemo_relay_scope_role"] = "subagent"
         context = contextvars.Context()
-        session.handle = self._push_session_scope(context, handle=parent_handle, metadata=scope_metadata, **push_kwargs)
+        args = (self.relay.scope.push, SESSION_SCOPE, self.relay.ScopeType.Agent)
+        push_kwargs.update(handle=parent_handle, metadata=scope_metadata, input={})
+        try:
+            future = _scope_op_executor().submit(context.run, *args, **push_kwargs)
+            session.handle = future.result(timeout=_SCOPE_OP_TIMEOUT)
+        except RuntimeError:
+            if not exit_fallback:
+                raise
+            session.handle = context.run(*args, **push_kwargs)
         session.context = context
 
     def ensure_session(

agent/transports/__init__.py

@@ -2,6 +2,7 @@
     transport = get_transport("anthropic_messages")
     result = transport.normalize_response(raw_response)"""
 
+import contextlib
 import importlib
 
 from agent.transports.types import (  # noqa: F401
@@ -24,13 +25,10 @@ def register_transport(api_mode: str, transport_cls: type) -> None:
 
 def get_transport(api_mode: str):
     """Return a transport instance for ``api_mode``, or None so callers can fall back to the legacy path."""
-    if not _discovered:
+    # A directly-imported transport leaves the registry partial; (re)discover on first use and on misses.
+    if not _discovered or api_mode not in _REGISTRY:
         _discover_transports()
     cls = _REGISTRY.get(api_mode)
-    if cls is None:
-        # A directly-imported transport leaves the registry partial; rediscover on misses.
-        _discover_transports()
-        cls = _REGISTRY.get(api_mode)
     return None if cls is None else cls()
 
 
@@ -39,7 +37,5 @@ def _discover_transports() -> None:
     global _discovered
     _discovered = True
     for name in _TRANSPORT_MODULES:
-        try:
+        with contextlib.suppress(ImportError):
             importlib.import_module(f"agent.transports.{name}")
-        except ImportError:
-            pass