refactor(agent): one builder for the interrupted_during_api_call exit reason

The summary-interrupt path added a second copy of the string the loop's
interrupt path builds; turn_explainers matches its prefix, so both now
share interrupted_during_api_call_reason().

agent/interrupt_control.py

@@ -32,6 +32,12 @@ def interrupt_issuer(agent) -> Optional[str]:
     return str(reason).strip().replace(" ", "_")
 
 
+def interrupted_during_api_call_reason(agent) -> str:
+    """Turn exit reason for an API call cut short by an interrupt (``turn_explainers`` matches the prefix)."""
+    issuer = interrupt_issuer(agent)
+    return f"interrupted_during_api_call({issuer})" if issuer else "interrupted_during_api_call"
+
+
 def _fence_cancel_before_commit(fence, *, when_in_flight: bool, failure_log: str) -> None:
     """Call ``type(fence).cancel_before_commit(fence)`` when ``commit_in_flight`` matches.
 

agent/turn_finalizer.py

@@ -14,7 +14,7 @@ from typing import Any, Callable, List, Optional, Tuple
 
 from agent.codex_responses_adapter import _summarize_user_message_for_log
 from agent.delegation_context import is_dispatcher_owned_worker_context
-from agent.interrupt_control import interrupt_issuer
+from agent.interrupt_control import interrupted_during_api_call_reason
 from agent.turn_failure_copy import exit_reason_failure, stamp_failure
 from agent.context_compressor import _DB_PERSISTED_MARKER
 from agent.message_content import flatten_message_text
@@ -160,15 +160,12 @@ def _resolve_budget_fallback(
             try:
                 final_response = agent._handle_max_iterations(messages, api_call_count)
             except InterruptedError:
-                # Same surfacing as an interrupted loop API call (handle_api_interrupt):
-                # the turn is interrupted, so the pending interrupt message is returned
-                # for requeue instead of being cleared behind a fallback summary.
+                # The turn ends interrupted, so the pending interrupt message is returned
+                # for requeue instead of being cleared behind a fallback summary. A redirect
+                # also ends it: the budget is spent, so there is no loop to restart into.
                 from agent.conversation_loop import INTERRUPT_WAITING_FOR_MODEL_PREFIX
                 interrupted = True
-                _issuer = interrupt_issuer(agent)
-                _turn_exit_reason = (
-                    f"interrupted_during_api_call({_issuer})" if _issuer else "interrupted_during_api_call"
-                )
+                _turn_exit_reason = interrupted_during_api_call_reason(agent)
                 final_response = f"{INTERRUPT_WAITING_FOR_MODEL_PREFIX}{time.time() - _summary_start:.1f}s elapsed)."
 
     # A kanban worker must record a terminal outcome whether or not a fallback path

agent/turn_iteration_prep.py

@@ -17,7 +17,7 @@ from dataclasses import dataclass
 from typing import Any, Dict
 
 from agent.display import KawaiiSpinner
-from agent.interrupt_control import interrupt_issuer
+from agent.interrupt_control import interrupt_issuer, interrupted_during_api_call_reason
 from agent.turn_context_compaction import _reanchor
 from agent.turn_truncation import boosted_output_cap
 
@@ -471,10 +471,7 @@ def apply_retry_restarts(
         return _verdict("continue")
 
     if interrupted:
-        _issuer = interrupt_issuer(agent)
-        _turn_exit_reason = (
-            f"interrupted_during_api_call({_issuer})" if _issuer else "interrupted_during_api_call"
-        )
+        _turn_exit_reason = interrupted_during_api_call_reason(agent)
         return _verdict("break")
 
     if _retry.restart_with_compressed_messages: