diff --git a/tasks.md b/tasks.md
index 77dd415..861a726 100644
--- a/tasks.md
+++ b/tasks.md
@@ -341,7 +341,7 @@
 ### M28. Регрессии на rollback и startup failure observability
 
 - Субагент: `test-engineer`
-- Статус: pending
+- Статус: completed
 - Зависимости: `M27`
 - Commit required: yes
 - Commit message: `add sandbox rollback regression tests`
diff --git a/test/test_create_http.py b/test/test_create_http.py
index e8686c4..ae302c2 100644
--- a/test/test_create_http.py
+++ b/test/test_create_http.py
@@ -3,6 +3,7 @@ import json
 from datetime import UTC, datetime, timedelta
 from uuid import UUID
 
+import pytest
 from docker import DockerClient
 from fastapi import FastAPI
 from starlette.types import Message, Scope
@@ -226,6 +227,16 @@ class FixedSandboxState:
         return list(self._sessions)
 
 
+class FailingSandboxState:
+    def __init__(self, error: Exception) -> None:
+        self._error = error
+        self.calls = 0
+
+    def list_active_sessions(self) -> list[SandboxSession]:
+        self.calls += 1
+        raise self._error
+
+
 class CountingRegistry:
     def __init__(self, count_active_result: int) -> None:
         self._count_active_result = count_active_result
@@ -238,6 +249,25 @@ class CountingRegistry:
         return self._count_active_result
 
 
+class FailingRegistry:
+    def __init__(self, error: Exception, *, fail_on: str = 'replace_all') -> None:
+        self._error = error
+        self._fail_on = fail_on
+        self.replaced_sessions: list[SandboxSession] = []
+        self.count_calls = 0
+
+    def replace_all(self, sessions: list[SandboxSession]) -> None:
+        self.replaced_sessions = list(sessions)
+        if self._fail_on == 'replace_all':
+            raise self._error
+
+    def count_active(self) -> int:
+        self.count_calls += 1
+        if self._fail_on == 'count_active':
+            raise self._error
+        return 0
+
+
 def build_config() -> AppConfig:
     return AppConfig(
         app=AppSectionConfig(name='master', env='test'),
@@ -719,6 +749,124 @@ def test_reconciliation_uses_registry_backed_active_count_metric() -> None:
     assert tracer.spans[0][2].attrs['sandbox.active_count'] == 7
 
 
+def test_reconciliation_records_error_when_state_source_fails() -> None:
+    logger = FakeLogger()
+    metrics = RecordingMetrics()
+    tracer = RecordingTracer()
+    state_error = RuntimeError('state_failed')
+    state_source = FailingSandboxState(state_error)
+    reconciler = SandboxSessionReconciler(
+        state_source=state_source,
+        registry=CountingRegistry(count_active_result=7),
+        logger=logger,
+        metrics=metrics,
+        tracer=tracer,
+    )
+
+    with pytest.raises(RuntimeError, match='state_failed') as excinfo:
+        reconciler.execute()
+
+    assert state_source.calls == 1
+    assert metrics.set_calls == []
+    spans = [
+        span
+        for name, _, span in tracer.spans
+        if name == 'adapter.sandbox.reconcile_sessions'
+    ]
+    assert spans
+    span = spans[0]
+    assert span.attrs['sandbox.result'] == 'error'
+    assert 'sandbox.discovered_count' not in span.attrs
+    assert 'sandbox.active_count' not in span.attrs
+    assert excinfo.value in span.errors
+
+
+def test_reconciliation_records_error_without_active_count_metric_on_registry_failure() -> (
+    None
+):
+    logger = FakeLogger()
+    metrics = RecordingMetrics()
+    tracer = RecordingTracer()
+    created_at = datetime(2026, 4, 2, 12, 0, tzinfo=UTC)
+    session = SandboxSession(
+        session_id=SESSION_ID,
+        chat_id=CHAT_ID,
+        container_id='container-123',
+        status=SandboxStatus.RUNNING,
+        created_at=created_at,
+        expires_at=created_at + timedelta(minutes=5),
+    )
+    registry_error = RuntimeError('replace_failed')
+    registry = FailingRegistry(registry_error)
+    reconciler = SandboxSessionReconciler(
+        state_source=FixedSandboxState([session]),
+        registry=registry,
+        logger=logger,
+        metrics=metrics,
+        tracer=tracer,
+    )
+
+    with pytest.raises(RuntimeError, match='replace_failed') as excinfo:
+        reconciler.execute()
+
+    assert registry.replaced_sessions == [session]
+    assert registry.count_calls == 0
+    assert metrics.set_calls == []
+    spans = [
+        span
+        for name, _, span in tracer.spans
+        if name == 'adapter.sandbox.reconcile_sessions'
+    ]
+    assert spans
+    span = spans[0]
+    assert span.attrs['sandbox.discovered_count'] == 1
+    assert span.attrs['sandbox.result'] == 'error'
+    assert 'sandbox.active_count' not in span.attrs
+    assert excinfo.value in span.errors
+
+
+def test_reconciliation_records_error_when_registry_count_active_fails() -> None:
+    logger = FakeLogger()
+    metrics = RecordingMetrics()
+    tracer = RecordingTracer()
+    created_at = datetime(2026, 4, 2, 12, 0, tzinfo=UTC)
+    session = SandboxSession(
+        session_id=SESSION_ID,
+        chat_id=CHAT_ID,
+        container_id='container-123',
+        status=SandboxStatus.RUNNING,
+        created_at=created_at,
+        expires_at=created_at + timedelta(minutes=5),
+    )
+    registry_error = RuntimeError('count_failed')
+    registry = FailingRegistry(registry_error, fail_on='count_active')
+    reconciler = SandboxSessionReconciler(
+        state_source=FixedSandboxState([session]),
+        registry=registry,
+        logger=logger,
+        metrics=metrics,
+        tracer=tracer,
+    )
+
+    with pytest.raises(RuntimeError, match='count_failed') as excinfo:
+        reconciler.execute()
+
+    assert registry.replaced_sessions == [session]
+    assert registry.count_calls == 1
+    assert metrics.set_calls == []
+    spans = [
+        span
+        for name, _, span in tracer.spans
+        if name == 'adapter.sandbox.reconcile_sessions'
+    ]
+    assert spans
+    span = spans[0]
+    assert span.attrs['sandbox.discovered_count'] == 1
+    assert 'sandbox.active_count' not in span.attrs
+    assert span.attrs['sandbox.result'] == 'error'
+    assert excinfo.value in span.errors
+
+
 def test_build_container_wires_observability_into_runtime_and_reconciler(
     monkeypatch,
 ) -> None:
diff --git a/test/test_docker_runtime.py b/test/test_docker_runtime.py
index 352adad..267d177 100644
--- a/test/test_docker_runtime.py
+++ b/test/test_docker_runtime.py
@@ -83,6 +83,7 @@ class FakeContainers:
         self.run_result = run_result or FakeContainer('container-123')
         self.get_result: FakeContainer | Exception | None = None
         self.list_result: list[object] = []
+        self.list_error: Exception | None = None
 
     def run(
         self,
@@ -114,6 +115,8 @@ class FakeContainers:
 
     def list(self, *, filters: dict[str, list[str]]) -> list[object]:
         self.list_calls.append({'filters': filters})
+        if self.list_error is not None:
+            raise self.list_error
         return self.list_result
 
 
@@ -690,3 +693,40 @@ def test_runtime_list_active_records_observability(tmp_path: Path) -> None:
         },
     )
     assert not span.errors
+
+
+def test_runtime_list_active_error_records_observability(tmp_path: Path) -> None:
+    config = build_config(tmp_path)
+    containers = FakeContainers()
+    containers.list_error = DockerException('boom')
+    metrics = RecordingMetrics()
+    tracer = RecordingTracer()
+    runtime = DockerSandboxRuntime(
+        config,
+        FakeDockerClient(containers),
+        metrics,
+        tracer,
+    )
+
+    with pytest.raises(SandboxError) as excinfo:
+        runtime.list_active_sessions()
+
+    assert str(excinfo.value) == 'sandbox_list_failed'
+    _find_increment_call(
+        metrics,
+        'sandbox.runtime.error.total',
+        attrs={'operation': 'list_active', 'error.type': 'DockerException'},
+    )
+    duration_call = _find_record_call(
+        metrics,
+        'sandbox.runtime.list_active.duration_ms',
+        attrs={'operation': 'list_active', 'result': 'error'},
+    )
+    assert duration_call[1] >= 0
+    span = _find_span(
+        tracer,
+        'adapter.docker.list_active_sandboxes',
+        span_attrs={'sandbox.result': 'error'},
+    )
+    assert isinstance(excinfo.value.__cause__, DockerException)
+    assert excinfo.value in span.errors