Fix home message tools calls

app/core/agent_session_buffer.py

@@ -0,0 +1,59 @@
+"""In-process TTL buffer for per-session LangChain message history.
+
+Stores the full message list (including AIMessage with tool_calls and ToolMessage)
+keyed by (user_id, session_id), so agents can reconstruct tool-call context across
+conversation turns without it being lossy through the wire.
+
+Single-process only. For multi-worker deployments, replace the _SessionBuffer
+implementation with one backed by Redis (serialize LangChain messages to dicts via
+message_to_dict / messages_from_dict from langchain_core.messages).
+"""
+from __future__ import annotations
+
+import time
+from threading import Lock
+
+from langchain_core.messages import BaseMessage
+
+SESSION_TTL_SECONDS = 1800  # 30-minute idle expiry
+MAX_MESSAGES_PER_SESSION = 80  # cap to avoid unbounded memory growth
+
+
+class _SessionBuffer:
+    def __init__(self) -> None:
+        self._store: dict[tuple[str, str], tuple[float, list[BaseMessage]]] = {}
+        self._lock = Lock()
+
+    def _evict_stale(self) -> None:
+        now = time.monotonic()
+        stale = [k for k, (ts, _) in self._store.items() if now - ts > SESSION_TTL_SECONDS]
+        for k in stale:
+            del self._store[k]
+
+    def get(self, user_id: str, session_id: str) -> list[BaseMessage] | None:
+        key = (user_id, session_id)
+        with self._lock:
+            entry = self._store.get(key)
+            if entry is None:
+                return None
+            ts, msgs = entry
+            if time.monotonic() - ts > SESSION_TTL_SECONDS:
+                del self._store[key]
+                return None
+            self._store[key] = (time.monotonic(), msgs)
+            return list(msgs)
+
+    def set(self, user_id: str, session_id: str, messages: list[BaseMessage]) -> None:
+        key = (user_id, session_id)
+        capped = messages[-MAX_MESSAGES_PER_SESSION:]
+        with self._lock:
+            self._evict_stale()
+            self._store[key] = (time.monotonic(), capped)
+
+    def clear(self, user_id: str, session_id: str) -> None:
+        with self._lock:
+            self._store.pop((user_id, session_id), None)
+
+
+# Module-level singleton — same pattern as _pending_states in api/app/api/routes/auth.py
+session_buffer = _SessionBuffer()