diff --git a/dev-docs/platforms/http-bot.md b/dev-docs/platforms/http-bot.md
index aa07e162f..1016fca9f 100644
--- a/dev-docs/platforms/http-bot.md
+++ b/dev-docs/platforms/http-bot.md
@@ -172,7 +172,9 @@ Stitch by `session_id` + `sequence`; the turn is complete when
 
 ## 7. Reset a session
 
-Start a fresh conversation for a `session_id` (drops history):
+Start a fresh conversation for a `session_id`. This resets Runner conversation
+state and hides prior history from future model calls, while retaining monitoring
+records. Other sessions are unaffected; an active task must finish before reset.
 
 ```
 POST /bots/{bot_uuid}/reset
diff --git a/src/langbot/pkg/platform/sources/http_bot.py b/src/langbot/pkg/platform/sources/http_bot.py
index 72c99d1c8..0aa8ac950 100644
--- a/src/langbot/pkg/platform/sources/http_bot.py
+++ b/src/langbot/pkg/platform/sources/http_bot.py
@@ -99,6 +99,7 @@ class _SyncCollector:
 class HttpBotAdapter(abstract_platform_adapter.AbstractMessagePlatformAdapter):
     """Standalone HTTP adapter (inbound webhook + outbound callbacks)."""
 
+    ap: typing.Any = pydantic.Field(default=None, exclude=True)
     bot_uuid: str = pydantic.Field(default='', exclude=True)
 
     listeners: dict[
@@ -377,7 +378,7 @@ class HttpBotAdapter(abstract_platform_adapter.AbstractMessagePlatformAdapter):
         return quart.jsonify({'code': 0, 'msg': 'reset', 'data': {'session_id': session_id, 'removed': removed}}), 200
 
     async def _reset_session(self, launcher_type: str, launcher_id: str) -> bool:
-        """Drop the matching session so the next message starts a fresh conversation."""
+        """Reset scoped Runner state and history through the shared context service."""
         execution_context = getattr(self.logger, 'execution_context', None)
         if (
             execution_context is None
@@ -387,30 +388,13 @@ class HttpBotAdapter(abstract_platform_adapter.AbstractMessagePlatformAdapter):
             or not self.bot_uuid
         ):
             raise RuntimeError('http_bot reset requires a trusted execution scope')
-        expected_prefix = (
-            execution_context.instance_uuid,
-            execution_context.workspace_uuid,
-            execution_context.placement_generation,
-            self.bot_uuid,
-            launcher_type,
-        )
-
-        sess_mgr = self.ap.sess_mgr
-        before = len(sess_mgr.session_list)
-        sess_mgr.session_list = [
-            s for s in sess_mgr.session_list if not self._matches_session_scope(s, expected_prefix, launcher_id)
-        ]
-        return len(sess_mgr.session_list) < before
-
-    @staticmethod
-    def _matches_session_scope(session, expected_prefix: tuple[str, str, int, str, str], launcher_id: str) -> bool:
-        session_key = getattr(session, '_langbot_session_key', None)
-        return (
-            isinstance(session_key, tuple)
-            and len(session_key) == 6
-            and session_key[:5] == expected_prefix
-            and str(session_key[5]) == launcher_id
-        )
+        try:
+            await self.ap.monitoring_service.reset_session_context(
+                execution_context, self.bot_uuid, f'{launcher_type}_{launcher_id}'
+            )
+        except LookupError:
+            return False
+        return True
 
     # -- outbound -------------------------------------------------------------
 
diff --git a/tests/unit_tests/api/service/test_session_context_reset.py b/tests/unit_tests/api/service/test_session_context_reset.py
index 43effa679..70989432f 100644
--- a/tests/unit_tests/api/service/test_session_context_reset.py
+++ b/tests/unit_tests/api/service/test_session_context_reset.py
@@ -154,3 +154,44 @@ async def test_reset_starts_new_external_runner_conversation(context_service):
     generation = await get_reset_generation(engine, 'w', 'b', 'person_u')
     assert isinstance(generation, str) and generation and generation not in {'remote-old', 'person_u'}
     assert snapshot['conversation']['external.conversation_id'] == generation
+
+
+@pytest.mark.asyncio
+async def test_signed_http_reset_uses_normal_adapter_wiring_and_clears_persisted_history(context_service):
+    import quart
+
+    from langbot.pkg.api.http.context import ExecutionContext
+    from langbot.pkg.platform.logger import EventLogger
+    from langbot.pkg.platform.sources.http_bot import HttpBotAdapter
+    from langbot.pkg.platform.sources import http_bot_signing as signing
+
+    service, engine = context_service
+    app = SimpleNamespace(monitoring_service=service)
+    context = ExecutionContext(instance_uuid='instance', workspace_uuid='w', placement_generation=1, bot_uuid='b')
+    adapter = HttpBotAdapter(
+        config={'inbound_secret': 'test-secret', 'signature_required': True},
+        logger=EventLogger('test', app, context, 'b'),
+    )
+    # Match BotManager's injection path; no synthetic attributes or model_construct.
+    assert hasattr(adapter, 'ap')
+    adapter.ap = app
+    adapter.set_bot_uuid('b')
+    store = TranscriptStore(engine)
+    for conversation in ('person_u', 'person_peer'):
+        await store.append_transcript(None, 'event', conversation, 'user', bot_id='b', workspace_id='w', content='old')
+    web = quart.Quart(__name__)
+    body = json.dumps({'session_id': 'u', 'session_type': 'person'}).encode()
+    timestamp, signature = signing.sign('test-secret', body)
+    async with web.test_request_context(
+        '/bots/b/reset',
+        method='POST',
+        data=body,
+        headers={signing.HEADER_TIMESTAMP: timestamp, signing.HEADER_SIGNATURE: signature},
+    ):
+        response, status = await adapter.handle_unified_webhook('b', 'reset', quart.request)
+        assert status == 200
+        assert (await response.get_json())['data'] == {'session_id': 'u', 'removed': True}
+    assert not (await store.page_transcript('person_u', bot_id='b', workspace_id='w'))[0]
+    assert (await store.page_transcript('person_peer', bot_id='b', workspace_id='w'))[0]
+    async with engine.connect() as conn:
+        assert (await conn.execute(sa.select(sa.func.count()).select_from(Transcript))).scalar() == 2
diff --git a/tests/unit_tests/platform/test_http_bot_tenancy.py b/tests/unit_tests/platform/test_http_bot_tenancy.py
index 8e19d143c..35fb2ccbe 100644
--- a/tests/unit_tests/platform/test_http_bot_tenancy.py
+++ b/tests/unit_tests/platform/test_http_bot_tenancy.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 import asyncio
 import time
 from types import SimpleNamespace
+from unittest.mock import AsyncMock
 
 import pytest
 
@@ -11,12 +12,6 @@ from langbot.pkg.platform.sources.http_bot import HttpBotAdapter
 from langbot.pkg.platform.sources import http_bot as http_bot_module
 
 
-def _session(key):
-    session = SimpleNamespace()
-    session._langbot_session_key = key
-    return session
-
-
 def _adapter(app, execution_context) -> HttpBotAdapter:
     adapter = HttpBotAdapter.model_construct(
         config={'signature_required': False},
@@ -27,38 +22,28 @@ def _adapter(app, execution_context) -> HttpBotAdapter:
         sync_waiters={},
         inbound_tasks=set(),
     )
-    object.__setattr__(adapter, 'ap', app)
+    assert hasattr(adapter, 'ap')  # BotManager only injects declared application fields.
+    adapter.ap = app
     return adapter
 
 
 @pytest.mark.asyncio
-async def test_http_bot_reset_removes_only_exact_execution_scope():
+@pytest.mark.parametrize('launcher_type', ['person', 'group'])
+async def test_http_bot_reset_uses_trusted_scope_and_persistent_context_service(launcher_type):
     context = ExecutionContext(
-        instance_uuid='instance-a',
-        workspace_uuid='workspace-a',
-        placement_generation=3,
-        bot_uuid='bot-a',
+        instance_uuid='instance-a', workspace_uuid='workspace-a', placement_generation=3, bot_uuid='bot-a'
     )
-    target_key = ('instance-a', 'workspace-a', 3, 'bot-a', 'person', 'shared-session')
-    retained_keys = [
-        ('instance-b', 'workspace-a', 3, 'bot-a', 'person', 'shared-session'),
-        ('instance-a', 'workspace-b', 3, 'bot-a', 'person', 'shared-session'),
-        ('instance-a', 'workspace-a', 4, 'bot-a', 'person', 'shared-session'),
-        ('instance-a', 'workspace-a', 3, 'bot-b', 'person', 'shared-session'),
-        ('instance-a', 'workspace-a', 3, 'bot-a', 'group', 'shared-session'),
-        ('instance-a', 'workspace-a', 3, 'bot-a', 'person', 'other-session'),
-    ]
-    sessions = [_session(target_key), *[_session(key) for key in retained_keys], SimpleNamespace()]
-    app = SimpleNamespace(sess_mgr=SimpleNamespace(session_list=sessions))
+    reset = AsyncMock(return_value={'reset': True})
+    app = SimpleNamespace(monitoring_service=SimpleNamespace(reset_session_context=reset))
     adapter = _adapter(app, context)
 
-    removed = await adapter._reset_session('person', 'shared-session')
-
-    assert removed is True
-    assert [getattr(session, '_langbot_session_key', None) for session in app.sess_mgr.session_list] == [
-        *retained_keys,
-        None,
-    ]
+    assert await adapter._reset_session(launcher_type, 'shared-session') is True
+    reset.assert_awaited_once_with(context, 'bot-a', f'{launcher_type}_shared-session')
+    reset.side_effect = LookupError('Session not found')
+    assert await adapter._reset_session(launcher_type, 'missing') is False
+    reset.side_effect = RuntimeError('Session is processing a task')
+    with pytest.raises(RuntimeError, match='processing'):
+        await adapter._reset_session(launcher_type, 'busy')
 
 
 @pytest.mark.asyncio