Fix Responses state after history compaction

Clear the active Responses provider continuation when automatic history compression or manual chat compaction rewrites local history, while preserving stored response IDs for cleanup.

Add focused regressions for both compression paths so compacted chats do not keep stale provider-side context.

helpers/history.py

@@ -723,6 +723,28 @@ def output_text(messages: list[OutputMessage], ai_label="ai", human_label="human
     return "\n".join(_stringify_output(o, ai_label, human_label) for o in messages)
 
 
+def clear_responses_provider_state(agent) -> None:
+    key = getattr(agent, "DATA_NAME_RESPONSES_STATE", "responses_state")
+    get_data = getattr(agent, "get_data", None)
+    set_data = getattr(agent, "set_data", None)
+    if not callable(get_data) or not callable(set_data):
+        return
+
+    state = get_data(key)
+    if not isinstance(state, dict):
+        return
+
+    state = dict(state)
+    removed = False
+    for field in ("response_id", "previous_response_id"):
+        if field in state:
+            state.pop(field, None)
+            removed = True
+
+    if removed:
+        set_data(key, state)
+
+
 def _merge_outputs(a: MessageContent, b: MessageContent) -> MessageContent:
     if isinstance(a, str) and isinstance(b, str):
         return a + "\n" + b

helpers/history.py.dox.md

@@ -65,6 +65,7 @@
 - `group_messages_abab(messages: list[BaseMessage]) -> list[BaseMessage]`
 - `output_langchain(messages: list[OutputMessage])`
 - `output_text(messages: list[OutputMessage], ai_label=..., human_label=...)`
+- `clear_responses_provider_state(agent) -> None`
 - `_merge_outputs(a: MessageContent, b: MessageContent) -> MessageContent`
 - `_merge_properties(a: Dict[str, MessageContent], b: Dict[str, MessageContent]) -> Dict[str, MessageContent]`
 - `_is_raw_message(obj: object) -> bool`
@@ -77,6 +78,7 @@
 
 - Helper modules own reusable framework APIs and must preserve public callers unless all callers, tests, and docs are updated together.
 - Update this file whenever public functions, classes, persistence behavior, path/security assumptions, side effects, or cross-module contracts change.
+- `clear_responses_provider_state(agent)` removes the active provider continuation IDs after local history rewrites while preserving stored response ID lists for later cleanup.
 - Observed side-effect areas: filesystem writes, filesystem deletion, model calls, plugin state, settings/state persistence, secret handling.
 - Imported dependency areas include: `abc`, `asyncio`, `collections`, `collections.abc`, `enum`, `helpers`, `json`, `langchain_core.messages`, `math`, `plugins._model_config.helpers.model_config`, `typing`, `uuid`.