diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index 0529635e0a..d964469e19 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -128,6 +128,7 @@ from open_webui.utils.task import (
 )
 from open_webui.utils.tools import (
     build_tool_server_headers,
+    get_attached_knowledge,
     get_builtin_tools,
     get_terminal_tools,
     get_tools,
@@ -2828,6 +2829,31 @@ async def process_chat_payload(request, form_data, user, metadata, model):
             # Add file context to user messages
             chat_id = metadata.get('chat_id')
             form_data['messages'] = await add_file_context(form_data.get('messages', []), chat_id, user)
+
+            if (model.get('info', {}).get('meta', {}).get('builtinTools') or {}).get('knowledge', True):
+                from html import escape
+
+                knowledge_tags = []
+                for item in get_attached_knowledge(model, metadata):
+                    if not item.get('id') or not item.get('type'):
+                        continue
+                    attrs = (
+                        f'type="{escape(str(item["type"]), quote=True)}" '
+                        f'id="{escape(str(item["id"]), quote=True)}"'
+                    )
+                    if item.get('name'):
+                        attrs += f' name="{escape(str(item["name"]), quote=True)}"'
+                    if item.get('source'):
+                        attrs += f' source="{escape(str(item["source"]), quote=True)}"'
+                    knowledge_tags.append(f'<knowledge {attrs}/>')
+
+                if knowledge_tags:
+                    form_data['messages'] = add_or_update_system_message(
+                        '<attached_knowledge>\n' + '\n'.join(knowledge_tags) + '\n</attached_knowledge>',
+                        form_data['messages'],
+                        append=True,
+                    )
+
             builtin_tools = await get_builtin_tools(
                 request,
                 {
diff --git a/backend/open_webui/utils/tools.py b/backend/open_webui/utils/tools.py
index ec372e78ce..1930837af8 100644
--- a/backend/open_webui/utils/tools.py
+++ b/backend/open_webui/utils/tools.py
@@ -475,6 +475,45 @@ async def get_tools(request: Request, tool_ids: list[str], user: UserModel, extr
     return tools_dict
 
 
+def get_attached_knowledge(model: dict, metadata: dict) -> list[dict]:
+    model_meta = model.get('info', {}).get('meta', {})
+    knowledge = []
+    seen = set()
+
+    for source, items in (
+        ('model', model_meta.get('knowledge') or []),
+        ('folder', metadata.get('folder_knowledge') or []),
+    ):
+        for item in items:
+            if not isinstance(item, dict):
+                continue
+            key = (item.get('type'), item.get('id'))
+            if not all(key) or key in seen:
+                continue
+            knowledge.append({**item, 'source': source})
+            seen.add(key)
+
+    file_context_enabled = (model_meta.get('capabilities') or {}).get('file_context', True)
+    if not file_context_enabled:
+        for item in metadata.get('files') or []:
+            if not isinstance(item, dict) or item.get('type') not in ('collection', 'note'):
+                continue
+            key = (item.get('type'), item.get('id'))
+            if not all(key) or key in seen:
+                continue
+            knowledge.append(
+                {
+                    'type': item.get('type'),
+                    'id': item.get('id'),
+                    'name': item.get('name'),
+                    'source': 'chat',
+                }
+            )
+            seen.add(key)
+
+    return knowledge
+
+
 async def get_builtin_tools(
     request: Request, extra_params: dict, features: dict = None, model: dict = None
 ) -> dict[str, dict]:
@@ -557,11 +596,7 @@ async def get_builtin_tools(
     # Knowledge base tools - conditional injection based on model knowledge
     # If model has attached knowledge (any type), only provide query_knowledge_files
     # Otherwise, provide all KB browsing tools
-    model_knowledge = model.get('info', {}).get('meta', {}).get('knowledge', [])
-    # Merge folder-attached knowledge so builtin tools can search it
-    folder_knowledge = extra_params.get('__metadata__', {}).get('folder_knowledge')
-    if folder_knowledge:
-        model_knowledge = list(model_knowledge or []) + list(folder_knowledge)
+    model_knowledge = get_attached_knowledge(model, metadata)
     if is_builtin_tool_enabled('knowledge'):
         from open_webui.env import ENABLE_KB_EXEC