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Update docstrings for store classes (#2616)
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# How to add semantic search to your LangGraph deployment
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This guide explains how to add semantic search to your LangGraph deployment's cross-thread [store](../../concepts/persistence.md#memory-store), so that your agent can search for memories and other documents by semantic similarity.
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## Prerequisites
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- A LangGraph deployment (see [how to deploy](setup_pyproject.md))
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- API keys for your embedding provider (in this case, OpenAI)
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- `langchain >= 0.3.8` (if you specify using the string format below)
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## Steps
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1. Update your `langgraph.json` configuration file to include the store configuration:
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```json
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{
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...
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"store": {
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"index": {
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"embed": "openai:text-embeddings-3-small",
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"dims": 1536,
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"fields": ["$"]
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}
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}
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}
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```
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This configuration:
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- Uses OpenAI's text-embeddings-3-small model for generating embeddings
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- Sets the embedding dimension to 1536 (matching the model's output)
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- Indexes all fields in your stored data (`["$"]` means index everything, or specify specific fields like `["text", "metadata.title"]`)
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2. To use the string embedding format above, make sure your dependencies include `langchain >= 0.3.8`:
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```toml
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# In pyproject.toml
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[project]
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dependencies = [
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"langchain>=0.3.8"
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]
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```
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Or if using requirements.txt:
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```
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langchain>=0.3.8
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```
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## Usage
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Once configured, you can use semantic search in your LangGraph nodes. The store requires a namespace tuple to organize memories:
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```python
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def search_memory(state: State, *, store: BaseStore):
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# Search the store using semantic similarity
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# The namespace tuple helps organize different types of memories
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# e.g., ("user_facts", "preferences") or ("conversation", "summaries")
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results = store.search(
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namespace=("memory", "facts"), # Organize memories by type
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query="your search query",
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k=3 # number of results to return
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)
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return results
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```
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## Custom Embeddings
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If you want to use custom embeddings, you can pass a path to a custom embedding function:
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```json
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{
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...
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"store": {
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"index": {
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"embed": "path/to/embedding_function.py:embed",
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"dims": 1536,
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"fields": ["$"]
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}
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}
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}
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```
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The deployment will look for the function in the specified path. The function must be async and accept a list of strings:
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```python
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# path/to/embedding_function.py
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from openai import AsyncOpenAI
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client = AsyncOpenAI()
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async def aembed_texts(texts: list[str]) -> list[list[float]]:
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"""Custom embedding function that must:
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1. Be async
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2. Accept a list of strings
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3. Return a list of float arrays (embeddings)
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"""
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response = await client.embeddings.create(
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model="text-embedding-3-small",
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input=texts
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)
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return [e.embedding for e in response.data]
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```
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## Querying via the API
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You can also query the store using the LangGraph SDK. Since the SDK uses async operations:
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```python
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from langgraph_sdk import get_client
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async def search_store():
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client = get_client()
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results = await client.store.search(
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namespace=("memory", "facts"),
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query="your search query",
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limit=3 # number of results to return
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)
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return results
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# Use in an async context
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results = await search_store()
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```
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@@ -171,7 +171,7 @@ trim_messages(
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## Long-term memory
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Long-term memory in LangGraph allows systems to retain information across different conversations or sessions. Unlike short-term memory, which is thread-scoped, long-term memory is saved within custom "namespaces."
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Long-term memory in LangGraph allows systems to retain information across different conversations or sessions. Unlike short-term memory, which is **thread-scoped**, long-term memory is saved within custom "namespaces."
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### Storing memories
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@@ -180,16 +180,34 @@ LangGraph stores long-term memories as JSON documents in a [store](persistence.m
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```python
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from langgraph.store.memory import InMemoryStore
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def embed(texts: list[str]) -> list[list[float]]:
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# Replace with an actual embedding function or LangChain embeddings object
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return [[1.0, 2.0] * len(texts)]
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# InMemoryStore saves data to an in-memory dictionary. Use a DB-backed store in production use.
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store = InMemoryStore()
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store = InMemoryStore(index={"embed": embed, "dims": 2})
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user_id = "my-user"
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application_context = "chitchat"
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namespace = (user_id, application_context)
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store.put(namespace, "a-memory", {"rules": ["User likes short, direct language", "User only speaks English & python"], "my-key": "my-value"})
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store.put(
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namespace,
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"a-memory",
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{
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"rules": [
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"User likes short, direct language",
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"User only speaks English & python",
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],
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"my-key": "my-value",
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},
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)
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# get the "memory" by ID
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item = store.get(namespace, "a-memory")
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# list "memories" within this namespace, filtering on content equivalence
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items = store.search(namespace, filter={"my-key": "my-value"})
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# search for "memories" within this namespace, filtering on content equivalence, sorted by vector similarity
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items = store.search(
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namespace, filter={"my-key": "my-value"}, query="language preferences"
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)
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```
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### Framework for thinking about long-term memory
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@@ -232,7 +250,7 @@ Alternatively, memories can be a collection of documents that are continuously u
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However, this shifts some complexity memory updating. The model must now _delete_ or _update_ existing items in the list, which can be tricky. In addition, some models may default to over-inserting and others may default to over-updating. See the [Trustcall](https://github.com/hinthornw/trustcall) package for one way to manage this and consider evaluation (e.g., with a tool like [LangSmith](https://docs.smith.langchain.com/tutorials/Developers/evaluation)) to help you tune the behavior.
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Working with document collections also shifts complexity to memory **search** over the list. The `Store` currently supports [filtering by metadata](https://langchain-ai.github.io/langgraph/reference/store/#storage) and will soon add [semantic search shortly](https://python.langchain.com/docs/concepts/vectorstores/), but selecting the most relevant documents can be tricky as the list grows.
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Working with document collections also shifts complexity to memory **search** over the list. The `Store` currently supports both [semantic search](https://langchain-ai.github.io/langgraph/reference/store/#langgraph.store.base.SearchOp.query) and [filtering by content](https://langchain-ai.github.io/langgraph/reference/store/#langgraph.store.base.SearchOp.filter).
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Finally, using a collection of memories can make it challenging to provide comprehensive context to the model. While individual memories may follow a specific schema, this structure might not capture the full context or relationships between memories. As a result, when using these memories to generate responses, the model may lack important contextual information that would be more readily available in a unified profile approach.
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@@ -41,6 +41,9 @@
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" <p>\n",
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" Support for the <code><a href=\"https://langchain-ai.github.io/langgraph/reference/store/#langgraph.store.base.BaseStore\">Store</a></code> API that is used in this guide was added in LangGraph <code>v0.2.32</code>.\n",
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" </p>\n",
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" <p>\n",
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" Support for <b>index</b> and <b>query</b> arguments of the <code><a href=\"https://langchain-ai.github.io/langgraph/reference/store/#langgraph.store.base.BaseStore\">Store</a></code> API that is used in this guide was added in LangGraph <code>v0.2.54</code>.\n",
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" </p>\n",
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"</div>\n",
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"\n",
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"## Setup\n",
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@@ -114,7 +117,7 @@
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"\n",
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"Importantly, to determine the user, we will be passing `user_id` via the config keyword argument of the node function.\n",
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"\n",
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"Let's first define an `InMemoryStore` which is already populated with some memories about the users."
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"Let's first define an `InMemoryStore` already populated with some memories about the users."
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]
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},
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{
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@@ -125,8 +128,14 @@
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"outputs": [],
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"source": [
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"from langgraph.store.memory import InMemoryStore\n",
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"from langchain_openai import OpenAIEmbeddings\n",
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"\n",
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"in_memory_store = InMemoryStore()"
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"in_memory_store = InMemoryStore(\n",
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" index={\n",
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" \"embed\": OpenAIEmbeddings(model=\"text-embedding-3-small\"),\n",
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" \"dims\": 1536,\n",
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" }\n",
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")"
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]
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},
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{
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@@ -163,7 +172,7 @@
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"def call_model(state: MessagesState, config: RunnableConfig, *, store: BaseStore):\n",
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" user_id = config[\"configurable\"][\"user_id\"]\n",
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" namespace = (\"memories\", user_id)\n",
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" memories = store.search(namespace)\n",
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" memories = store.search(namespace, query=str(state[\"messages\"][-1].content))\n",
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" info = \"\\n\".join([d.value[\"data\"] for d in memories])\n",
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" system_msg = f\"You are a helpful assistant talking to the user. User info: {info}\"\n",
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"\n",
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@@ -39,6 +39,7 @@ LangGraph makes it easy to manage conversation [memory](../concepts/memory.md) i
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- [How to manage conversation history](memory/manage-conversation-history.ipynb)
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- [How to delete messages](memory/delete-messages.ipynb)
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- [How to add summary conversation memory](memory/add-summary-conversation-history.ipynb)
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- [Add long-term memory (cross-thread)](cross-thread-persistence.ipynb)
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### Human-in-the-loop
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@@ -139,6 +140,7 @@ Learn how to set up your app for deployment to LangGraph Platform:
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- [How to set up app for deployment (requirements.txt)](../cloud/deployment/setup.md)
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- [How to set up app for deployment (pyproject.toml)](../cloud/deployment/setup_pyproject.md)
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- [How to set up app for deployment (JavaScript)](../cloud/deployment/setup_javascript.md)
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- [How to add semantic search](../cloud/deployment/semantic_search.md)
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- [How to customize Dockerfile](../cloud/deployment/custom_docker.md)
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- [How to test locally](../cloud/deployment/test_locally.md)
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- [How to rebuild graph at runtime](../cloud/deployment/graph_rebuild.md)
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