diff --git a/nanobot/agent/autocompact.py b/nanobot/agent/autocompact.py
index 71cf262ff..3181dce74 100644
--- a/nanobot/agent/autocompact.py
+++ b/nanobot/agent/autocompact.py
@@ -102,11 +102,7 @@ class AutoCompact:
         finally:
             self._archiving.discard(key)
 
-    def prepare_session(
-        self,
-        session: Session,
-        key: str,
-    ) -> tuple[Session, SessionSummary | None]:
+    def prepare_session(self, session: Session, key: str) -> tuple[Session, SessionSummary | None]:
         if self._is_internal_session(key):
             self._archiving.discard(key)
             self._summaries.pop(key, None)
diff --git a/tests/agent/test_autocompact_unit.py b/tests/agent/test_autocompact_unit.py
index e33e903d9..7ceefcf7e 100644
--- a/tests/agent/test_autocompact_unit.py
+++ b/tests/agent/test_autocompact_unit.py
@@ -686,10 +686,7 @@ class TestPrepareSession:
         ac.sessions = mock_sm
         key = "dream:20260602-155256"
         ac._archiving.add(key)
-        ac._summaries[key] = SessionSummary(
-            "Hot summary.",
-            datetime(2026, 6, 2, 15, 52, 56),
-        )
+        ac._summaries[key] = SessionSummary("Hot summary.", datetime(2026, 6, 2, 15, 52, 56))
         session = _make_session(
             key=key,
             updated_at=datetime.now() - timedelta(minutes=20),
diff --git a/tests/agent/test_context_builder.py b/tests/agent/test_context_builder.py
index 333f990b5..d30a4941d 100644
--- a/tests/agent/test_context_builder.py
+++ b/tests/agent/test_context_builder.py
@@ -332,24 +332,16 @@ class TestBuildSystemPrompt:
 
     def test_includes_session_summary(self, tmp_path):
         builder = _builder(tmp_path)
-        result = builder.build_system_prompt(
-            session_summary=SessionSummary(
-                text="Previous chat about Python.",
-                last_active=datetime(2026, 8, 19, 10, 0),
-            )
-        )
+        summary = SessionSummary("Previous chat about Python.", datetime(2026, 8, 19, 10, 0))
+        result = builder.build_system_prompt(session_summary=summary)
         assert "Previous chat about Python." in result
         assert "[Archived Context Summary]" in result
 
     def test_sections_separated_by_separator(self, tmp_path):
         (tmp_path / "AGENTS.md").write_text("Rules.", encoding="utf-8")
         builder = _builder(tmp_path)
-        result = builder.build_system_prompt(
-            session_summary=SessionSummary(
-                text="Summary.",
-                last_active=datetime(2026, 8, 19, 10, 0),
-            )
-        )
+        summary = SessionSummary("Summary.", datetime(2026, 8, 19, 10, 0))
+        result = builder.build_system_prompt(session_summary=summary)
         assert "\n\n---\n\n" in result
 
     def test_no_bootstrap_no_summary(self, tmp_path):
diff --git a/tests/agent/test_context_prompt_cache.py b/tests/agent/test_context_prompt_cache.py
index c07f51e84..39dc8fb1b 100644
--- a/tests/agent/test_context_prompt_cache.py
+++ b/tests/agent/test_context_prompt_cache.py
@@ -121,10 +121,7 @@ def test_session_summary_replaces_matching_recent_history_entry(tmp_path) -> Non
 
     builder.memory.append_history("another session event", session_key=session_key)
     summary_cursor = builder.memory.append_history(overview, session_key=session_key)
-    summary = SessionSummary(
-        text=overview,
-        last_active=real_datetime(2026, 8, 19, 10, 0),
-    )
+    summary = SessionSummary(overview, real_datetime(2026, 8, 19, 10, 0))
 
     prompt = builder.build_system_prompt(
         session_key=session_key,
diff --git a/tests/agent/test_loop_consolidation_tokens.py b/tests/agent/test_loop_consolidation_tokens.py
index b5549351d..d0685f83d 100644
--- a/tests/agent/test_loop_consolidation_tokens.py
+++ b/tests/agent/test_loop_consolidation_tokens.py
@@ -213,13 +213,7 @@ async def test_preflight_consolidation_receives_pending_summary(tmp_path) -> Non
     loop = _make_loop(tmp_path, estimated_tokens=100, context_window_tokens=200)
     session = loop.sessions.get_or_create("cli:test")
     loop.auto_compact.prepare_session = MagicMock(
-        return_value=(
-            session,
-            SessionSummary(
-                text="earlier context",
-                last_active=session.updated_at,
-            ),
-        )
+        return_value=(session, SessionSummary("earlier context", session.updated_at))
     )  # type: ignore[method-assign]
     loop.consolidator.maybe_consolidate_by_tokens = AsyncMock(return_value=None)  # type: ignore[method-assign]
     loop.schedule_background = lambda coro: coro.close()  # type: ignore[method-assign]