{"record":{"id":"7d680a209564cb55","repo":"mem0ai/mem0","slug":"the-langchain-community-library-is-required-ple-7d680a","errorCode":null,"errorMessage":"The 'langchain_community' library is required. Please install it using 'pip install langchain_community'.","messagePattern":"The 'langchain_community' library is required\\. Please install it using 'pip install langchain_community'\\.","errorType":"exception","errorClass":"ImportError","httpStatus":null,"severity":"error","filePath":"mem0/vector_stores/langchain.py","lineNumber":9,"sourceCode":"import logging\nfrom typing import Dict, List, Optional\n\nfrom pydantic import BaseModel\n\ntry:\n    from langchain_community.vectorstores import VectorStore\nexcept ImportError:\n    raise ImportError(\n        \"The 'langchain_community' library is required. Please install it using 'pip install langchain_community'.\"\n    )\n\nfrom mem0.vector_stores.base import VectorStoreBase\n\nlogger = logging.getLogger(__name__)\n\n\nclass OutputData(BaseModel):\n    id: Optional[str]  # memory id\n    score: Optional[float]  # distance\n    payload: Optional[Dict]  # metadata\n\n\n# Methods that accept a pre-computed embedding and return (Document, float) pairs.\n# Tried in order; first match wins. Not part of the base VectorStore contract,\n# but exposed by several concrete implementations.\n_SCORED_BY_VECTOR_METHODS = [","sourceCodeStart":1,"sourceCodeEnd":27,"githubUrl":"https://github.com/mem0ai/mem0/blob/001c235229be8795e3834520467bd0d661ed8f34/mem0/vector_stores/langchain.py#L1-L27","documentation":"Module-level ImportError raised when mem0.vector_stores.langchain is imported but langchain_community is not installed. The module hard-depends on langchain_community.vectorstores.VectorStore at import time, so merely importing the module without the package fails.","triggerScenarios":"Selecting vector_store provider 'langchain' in MemoryConfig, or importing mem0.vector_stores.langchain, in an environment where pip install langchain_community was never run.","commonSituations":"Fresh installs using only 'pip install mem0ai' (langchain is an optional extra); deploying to slim Docker images; adding the langchain provider to an existing app without updating requirements.","solutions":["pip install langchain_community (or add it to requirements.txt / the Docker image)","Use a dedicated extra if provided (e.g. mem0ai[lc] style extras) so the dependency is declared","If langchain was unintended, switch the provider back to faiss/qdrant/chroma etc."],"exampleFix":"# before\n# provider='langchain' without the package -> ImportError at import time\n\n# after\n# shell: pip install langchain_community\nfrom mem0.vector_stores.langchain import LCVectorStore","handlingStrategy":"fallback","validationCode":"try:\n    import langchain_community  # noqa\n    HAVE_LC = True\nexcept ImportError:\n    HAVE_LC = False\n\nprovider = 'langchain' if HAVE_LC else 'faiss'","typeGuard":null,"tryCatchPattern":"try:\n    from mem0.vector_stores.langchain import LCVectorStore\nexcept ImportError as e:\n    raise RuntimeError('Run: pip install langchain_community') from e","preventionTips":["Declare langchain_community in requirements when using the langchain provider","Smoke-test provider imports in CI for every configured vector store"],"tags":["langchain","vector-store","import-error","dependencies"],"backgroundTag":null,"analyzedSha":"001c235229be8795e3834520467bd0d661ed8f34","analyzedAt":"2026-08-15T01:55:42.685Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}