fix: salvage a crashed run's full history into the session so revival loses no context

strix/core/execution.py

@@ -30,6 +30,7 @@ from strix.core.inputs import child_initial_input
 from strix.core.sessions import (
     enforce_image_budget,
     open_agent_session,
+    replace_session_items,
     seed_initial_input,
     strip_all_images_from_session,
 )
@@ -117,6 +118,29 @@ def _transient_model_retry_delay(attempt: int) -> float:
     return min(delay, _TRANSIENT_MODEL_RETRY_MAX_DELAY_S)
 
 
+async def _salvage_stream_to_session(
+    session: Session,
+    pre_run_items: list[Any],
+    stream: Any,
+    agent_id: str,
+) -> None:
+    """Persist a crashed run's full history so a revived agent loses no context."""
+    if stream is None:
+        return
+    try:
+        replay = list(stream.to_input_list())
+    except Exception:
+        logger.exception("could not build salvage history for %s", agent_id)
+        return
+    desired = list(pre_run_items) + replay
+    if len(desired) <= len(pre_run_items):
+        return
+    try:
+        await replace_session_items(session, desired)
+    except Exception:
+        logger.exception("salvaging crashed run history failed for %s", agent_id)
+
+
 async def _seed_and_prepare_first_input(
     session: Session | None, initial_input: Any, *, start_parked: bool
 ) -> Any:
@@ -534,6 +558,8 @@ async def _run_cycle(  # noqa: PLR0912, PLR0915
     compactions = 0
     model_retries = 0
     while True:
+        stream: Any = None
+        pre_run_items: list[Any] = []
         try:
             await coordinator.mark_running(agent_id)
             if session is not None:
@@ -547,6 +573,8 @@ async def _run_cycle(  # noqa: PLR0912, PLR0915
                     await _compact_session(agent, session, run_config, force=False)
                 except Exception:
                     logger.exception("proactive compaction failed for %s", agent_id)
+                with contextlib.suppress(Exception):
+                    pre_run_items = list(await session.get_items())
             stream = Runner.run_streamed(
                 agent,
                 input=input_data,
@@ -657,6 +685,8 @@ async def _run_cycle(  # noqa: PLR0912, PLR0915
                 if session is not None:
                     input_data = []
                 continue
+            if session is not None:
+                await _salvage_stream_to_session(session, pre_run_items, stream, agent_id)
             if not interactive:
                 raise
             if isinstance(exc, MaxTurnsExceeded):
@@ -671,7 +701,7 @@ async def _run_cycle(  # noqa: PLR0912, PLR0915
             return None
         else:
             await _settle_run_result(coordinator, agent_id, interactive)
-            return stream
+            return cast("RunResultBase | None", stream)
 
 
 async def _settle_run_result(

tests/test_execution.py

@@ -595,6 +595,44 @@ async def test_run_cycle_parked_parks_instead_of_raising(
     assert coordinator.errors["root"] == "unexpected explosion"
 
 
+class _SalvageStream:
+    def __init__(self, replay: list[dict[str, Any]]) -> None:
+        self._replay = replay
+
+    def to_input_list(self) -> list[dict[str, Any]]:
+        return self._replay
+
+
+@pytest.mark.asyncio
+async def test_salvage_stream_to_session_preserves_full_history(tmp_path: Any) -> None:
+    session = SQLiteSession("child", tmp_path / "agents.db")
+    await session.add_items([{"role": "user", "content": "identity + task"}])
+    pre_run = list(await session.get_items())
+
+    # A crash mid-run: the stream produced two turns the SDK never committed.
+    stream = _SalvageStream(
+        [
+            {"role": "assistant", "content": "recon turn 1"},
+            {"role": "assistant", "content": "recon turn 2"},
+        ]
+    )
+    await execution._salvage_stream_to_session(session, pre_run, stream, "child")
+
+    stored = [cast("dict[str, Any]", i) for i in await session.get_items()]
+    assert [i["content"] for i in stored] == [
+        "identity + task",
+        "recon turn 1",
+        "recon turn 2",
+    ]
+
+    # A crash with nothing new to salvage leaves the session untouched.
+    await execution._salvage_stream_to_session(
+        session, list(await session.get_items()), _SalvageStream([]), "child"
+    )
+    assert len(await session.get_items()) == 3
+    session.close()
+
+
 @pytest.mark.asyncio
 async def test_seed_initial_input_persists_and_is_idempotent(tmp_path: Any) -> None:
     session = SQLiteSession("child", tmp_path / "agents.db")