fix(compaction): chain any input filter already set on the run config

The image scrub for text-only models also sets call_model_input_filter; replacing it dropped the scrub.

strix/core/execution.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import asyncio
 import contextlib
+import inspect
 import logging
 import uuid
 from collections.abc import Callable
@@ -147,22 +148,27 @@ def _with_compaction_check(run_config: RunConfig) -> RunConfig:
     model = _run_config_model(run_config)
     if model is None:
         return run_config
+    inner = run_config.call_model_input_filter
     first_call = True
 
     async def _check(data: CallModelData[Any]) -> ModelInputData:
         nonlocal first_call
+        model_data = data.model_data
+        if inner is not None:
+            result = inner(data)
+            model_data = await result if inspect.isawaitable(result) else result
         # Skip the first call: the cycle compacts right before the run, and the run's
         # new input is only persisted after this filter, so stopping here would lose it.
         if not first_call and await asyncio.to_thread(
             needs_compaction,
             model,
-            data.model_data.instructions or "",
+            model_data.instructions or "",
             _agent_tools_text(data.agent),
-            data.model_data.input,
+            model_data.input,
         ):
             raise CompactionNeededError(model)
         first_call = False
-        return data.model_data
+        return model_data
 
     return replace(run_config, call_model_input_filter=_check)
 

tests/test_execution.py

@@ -1553,6 +1553,26 @@ async def test_compaction_check_stops_run_after_first_call_when_over_budget(
         await guard(data)
 
 
+@pytest.mark.asyncio
+async def test_compaction_check_chains_an_existing_input_filter(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    seen: list[Any] = []
+    monkeypatch.setattr(execution, "needs_compaction", lambda *args: seen.append(args[3]))
+    filtered = ModelInputData(input=[{"role": "user", "content": "scrubbed"}], instructions="sys")
+    run_config = RunConfig(model="m", call_model_input_filter=lambda _data: filtered)
+    check: Any = execution._with_compaction_check(run_config).call_model_input_filter
+    data = CallModelData(
+        model_data=ModelInputData(input=[], instructions="sys"),
+        agent=MagicMock(tools=[]),
+        context=None,
+    )
+
+    assert await check(data) is filtered
+    assert await check(data) is filtered
+    assert seen == [filtered.input]
+
+
 class _BudgetStream:
     def __init__(self, exc: BaseException | None) -> None:
         self.run_loop_exception = exc