diff --git a/api/core/app/workflow/node_factory.py b/api/core/app/workflow/node_factory.py
index 970b0c4c3d..3a82f0a45e 100644
--- a/api/core/app/workflow/node_factory.py
+++ b/api/core/app/workflow/node_factory.py
@@ -16,6 +16,7 @@ from core.helper.ssrf_proxy import ssrf_proxy
 from core.memory.token_buffer_memory import TokenBufferMemory
 from core.model_manager import ModelInstance
 from core.model_runtime.entities.model_entities import ModelType
+from core.model_runtime.memory import PromptMessageMemory
 from core.model_runtime.model_providers.__base.large_language_model import LargeLanguageModel
 from core.prompt.entities.advanced_prompt_entities import MemoryConfig
 from core.rag.retrieval.dataset_retrieval import DatasetRetrieval
@@ -35,7 +36,6 @@ from core.workflow.nodes.knowledge_retrieval.knowledge_retrieval_node import Kno
 from core.workflow.nodes.llm.entities import ModelConfig
 from core.workflow.nodes.llm.exc import LLMModeRequiredError, ModelNotExistError
 from core.workflow.nodes.llm.node import LLMNode
-from core.workflow.nodes.llm.protocols import PromptMessageMemory
 from core.workflow.nodes.node_mapping import LATEST_VERSION, NODE_TYPE_CLASSES_MAPPING
 from core.workflow.nodes.parameter_extractor.parameter_extractor_node import ParameterExtractorNode
 from core.workflow.nodes.question_classifier.question_classifier_node import QuestionClassifierNode
diff --git a/api/core/model_runtime/memory/__init__.py b/api/core/model_runtime/memory/__init__.py
new file mode 100644
index 0000000000..2d954486c3
--- /dev/null
+++ b/api/core/model_runtime/memory/__init__.py
@@ -0,0 +1,3 @@
+from .prompt_message_memory import DEFAULT_MEMORY_MAX_TOKEN_LIMIT, PromptMessageMemory
+
+__all__ = ["DEFAULT_MEMORY_MAX_TOKEN_LIMIT", "PromptMessageMemory"]
diff --git a/api/core/model_runtime/memory/prompt_message_memory.py b/api/core/model_runtime/memory/prompt_message_memory.py
new file mode 100644
index 0000000000..4491ddfd05
--- /dev/null
+++ b/api/core/model_runtime/memory/prompt_message_memory.py
@@ -0,0 +1,18 @@
+from __future__ import annotations
+
+from collections.abc import Sequence
+from typing import Protocol
+
+from core.model_runtime.entities import PromptMessage
+
+DEFAULT_MEMORY_MAX_TOKEN_LIMIT = 2000
+
+
+class PromptMessageMemory(Protocol):
+    """Port for loading memory as prompt messages."""
+
+    def get_history_prompt_messages(
+        self, max_token_limit: int = DEFAULT_MEMORY_MAX_TOKEN_LIMIT, message_limit: int | None = None
+    ) -> Sequence[PromptMessage]:
+        """Return historical prompt messages constrained by token/message limits."""
+        ...
diff --git a/api/core/workflow/nodes/llm/node.py b/api/core/workflow/nodes/llm/node.py
index 475a904d1c..c06db0dc16 100644
--- a/api/core/workflow/nodes/llm/node.py
+++ b/api/core/workflow/nodes/llm/node.py
@@ -37,6 +37,7 @@ from core.model_runtime.entities.message_entities import (
     UserPromptMessage,
 )
 from core.model_runtime.entities.model_entities import ModelFeature, ModelPropertyKey
+from core.model_runtime.memory import PromptMessageMemory
 from core.model_runtime.utils.encoders import jsonable_encoder
 from core.prompt.entities.advanced_prompt_entities import CompletionModelPromptTemplate, MemoryConfig
 from core.prompt.utils.prompt_message_util import PromptMessageUtil
@@ -62,7 +63,7 @@ from core.workflow.node_events import (
 from core.workflow.nodes.base.entities import VariableSelector
 from core.workflow.nodes.base.node import Node
 from core.workflow.nodes.base.variable_template_parser import VariableTemplateParser
-from core.workflow.nodes.llm.protocols import CredentialsProvider, ModelFactory, PromptMessageMemory
+from core.workflow.nodes.llm.protocols import CredentialsProvider, ModelFactory
 from core.workflow.runtime import VariablePool
 from core.workflow.variables import (
     ArrayFileSegment,
diff --git a/api/core/workflow/nodes/llm/protocols.py b/api/core/workflow/nodes/llm/protocols.py
index 5bca04165a..8e0365299d 100644
--- a/api/core/workflow/nodes/llm/protocols.py
+++ b/api/core/workflow/nodes/llm/protocols.py
@@ -1,10 +1,8 @@
 from __future__ import annotations
 
-from collections.abc import Sequence
 from typing import Any, Protocol
 
 from core.model_manager import ModelInstance
-from core.model_runtime.entities import PromptMessage
 
 
 class CredentialsProvider(Protocol):
@@ -21,13 +19,3 @@ class ModelFactory(Protocol):
     def init_model_instance(self, provider_name: str, model_name: str) -> ModelInstance:
         """Create a model instance that is ready for schema lookup and invocation."""
         ...
-
-
-class PromptMessageMemory(Protocol):
-    """Port for loading memory as prompt messages for LLM nodes."""
-
-    def get_history_prompt_messages(
-        self, max_token_limit: int = 2000, message_limit: int | None = None
-    ) -> Sequence[PromptMessage]:
-        """Return historical prompt messages constrained by token/message limits."""
-        ...