refactor(agent): module-level _refund_api_call import; int verdict count (#77305)

turn_context_compaction imports neither conversation_loop nor
turn_empty_response, so the function-local import is not guarding a
cycle. The helper's docstring now also covers the provider-switch
fallback hop that reached the provider.

agent/turn_context_compaction.py

@@ -101,7 +101,8 @@ def _apply_grown_window(agent: Any, compressor: Any, grown: int) -> None:
 
 
 def _refund_api_call(agent: Any, api_call_count: int) -> int:
-    """A pass that never reached the provider refunds the call count and budget."""
+    """Refund the call count and iteration budget for a pass that should not consume it:
+    one that never reached the provider (preflight) or a provider-switch fallback hop."""
     # Host progress-aware timeout (#98722, salvaged from #98741): this preflight iteration never reached the
     # provider. Refund its provisional call/budget exactly like a successful pre-API compaction, then stop
     # before the unchanged oversized request reaches the provider — its overflow error would only invoke

agent/turn_empty_response.py

@@ -16,6 +16,7 @@ from typing import Any, Dict, List, Optional
 
 from agent import empty_response_guard as _empty_guard
 from agent.message_metadata import append_message
+from agent.turn_context_compaction import _refund_api_call
 from agent.turn_failure_copy import site_copy
 from agent.turn_recovery import interruptible_backoff_sleep
 
@@ -283,7 +284,6 @@ def recover_empty_response(
             _preflight_compression_blocked = False
             # The fallback hop is a provider switch, not a model turn: refund the empty
             # call so a mid-turn fallback doesn't eat the iteration budget (#77305).
-            from agent.turn_context_compaction import _refund_api_call
             api_call_count = _refund_api_call(agent, api_call_count)
             return _verdict("continue")
 

agent/turn_final_response.py

@@ -40,7 +40,7 @@ class FinalResponseVerdict:
     length_continue_retries: Any
     _pending_verification_response: Any
     _pending_verification_response_previewed: Any
-    api_call_count: Any
+    api_call_count: int
     result: Optional[Dict[str, Any]] = None