references: chat reference resolver

surfsense_backend/app/agents/chat/runtime/references/chat/resolver.py

@@ -0,0 +1,41 @@
+"""Resolve ``@chat`` mentions into pointer references.
+
+Chats are not KB-indexed, so a chat reference is a pointer only; its turns are
+read on demand via the chat read tool, not injected here. Only the title is
+needed, so this takes the cheap access-checked path and never loads transcripts.
+"""
+
+from __future__ import annotations
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from ..models import ChatReference
+from .access import accessible_threads
+
+
+async def resolve_chat_references(
+    session: AsyncSession,
+    *,
+    search_space_id: int,
+    requesting_user_id: str | None,
+    current_chat_id: int,
+    thread_ids: list[int],
+) -> list[ChatReference]:
+    """Map ``@chat`` thread ids to access-checked pointers (titles only)."""
+    if not thread_ids:
+        return []
+
+    threads = await accessible_threads(
+        session,
+        search_space_id=search_space_id,
+        requesting_user_id=requesting_user_id,
+        thread_ids=thread_ids,
+        exclude_thread_id=current_chat_id,
+    )
+    return [
+        ChatReference(entity_id=thread.id, label=str(thread.title or "Untitled chat"))
+        for thread in threads
+    ]
+
+
+__all__ = ["resolve_chat_references"]