{"record":{"id":"27fa46f6a19367c0","repo":"FoundationAgents/MetaGPT","slug":"llama-index-postprocessor-flag-embedding-reranker","errorCode":null,"errorMessage":"`llama-index-postprocessor-flag-embedding-reranker` package not found, please run `pip install llama-index-postprocessor-flag-embedding-reranker`","messagePattern":"`llama-index-postprocessor-flag-embedding-reranker` package not found, please run `pip install llama-index-postprocessor-flag-embedding-reranker`","errorType":"exception","errorClass":"ImportError","httpStatus":null,"severity":"error","filePath":"metagpt/rag/factories/ranker.py","lineNumber":68,"sourceCode":"            )\n        return ColbertRerank(**config.model_dump())\n\n    def _create_cohere_rerank(self, config: CohereRerankConfig, **kwargs) -> LLMRerank:\n        try:\n            from llama_index.postprocessor.cohere_rerank import CohereRerank\n        except ImportError:\n            raise ImportError(\n                \"`llama-index-postprocessor-cohere-rerank` package not found, please run `pip install llama-index-postprocessor-cohere-rerank`\"\n            )\n        return CohereRerank(**config.model_dump())\n\n    def _create_bge_rerank(self, config: BGERerankConfig, **kwargs) -> LLMRerank:\n        try:\n            from llama_index.postprocessor.flag_embedding_reranker import (\n                FlagEmbeddingReranker,\n            )\n        except ImportError:\n            raise ImportError(\n                \"`llama-index-postprocessor-flag-embedding-reranker` package not found, please run `pip install llama-index-postprocessor-flag-embedding-reranker`\"\n            )\n        return FlagEmbeddingReranker(**config.model_dump())\n\n    def _create_object_ranker(self, config: ObjectRankerConfig, **kwargs) -> LLMRerank:\n        return ObjectSortPostprocessor(**config.model_dump())\n\n    def _extract_llm(self, config: BaseRankerConfig = None, **kwargs) -> LLM:\n        return self._val_from_config_or_kwargs(\"llm\", config, **kwargs)\n\n\nget_rankers = RankerFactory().get_rankers\n","sourceCodeStart":50,"sourceCodeEnd":81,"githubUrl":"https://github.com/FoundationAgents/MetaGPT/blob/11cdf466d042aece04fc6cfd13b28e1a70341b1f/metagpt/rag/factories/ranker.py#L50-L81","documentation":"RankerFactory._create_bge_rerank raises this ImportError when llama-index-postprocessor-flag-embedding-reranker is not installed. BGE reranking uses FlagEmbedding's FlagEmbeddingReranker, which llama-index ships as a separate optional distribution that MetaGPT never installs by default.","triggerScenarios":"Requesting a BGERerankConfig through get_rankers or a retriever/ranker config when the flag-embedding-reranker package (and its FlagEmbedding dependency) is missing.","commonSituations":"Opting into BGE reranking for local/CPU pipelines on a minimal install; CI images that install metagpt without rag extras; the additional transitive FlagEmbedding model dependencies (torch, transformers) not being present.","solutions":["pip install llama-index-postprocessor-flag-embedding-reranker","Verify FlagEmbedding itself imports (pip install FlagEmbedding) since the wrapper depends on it","If torch/model downloads are unacceptable in your env, use an API-backed ranker (cohere) or ObjectSortPostprocessor instead"],"exampleFix":"// before\nrankers = get_rankers(configs=[BGERerankConfig(top_n=3, model=\"BAAI/bge-reranker-base\")])  # ImportError\n\n// after\n// pip install llama-index-postprocessor-flag-embedding-reranker FlagEmbedding\nrankers = get_rankers(configs=[BGERerankConfig(top_n=3, model=\"BAAI/bge-reranker-base\")])","handlingStrategy":"validation","validationCode":"import importlib.util\nif importlib.util.find_spec(\"llama_index.postprocessor.flag_embedding_reranker\") is None:\n    raise SystemExit(\"Install first: pip install llama-index-postprocessor-flag-embedding-reranker FlagEmbedding\")","typeGuard":null,"tryCatchPattern":"try:\n    ranker = get_rankers(configs=[bge_cfg])\nexcept ImportError as e:\n    if \"flag-embedding-reranker\" in str(e):\n        raise RuntimeError(\"BGE rerank requires: pip install llama-index-postprocessor-flag-embedding-reranker\") from e\n    raise","preventionTips":["Add the flag-embedding reranker package (plus FlagEmbedding, torch) to environments using BGE rankers","Pre-download the BAAI reranker model in image build so runtime does not fetch multi-GB weights","Verify imports in a preflight check for CPU-only deployments"],"tags":["rag","reranker","dependency","bge","importerror"],"backgroundTag":null,"analyzedSha":"11cdf466d042aece04fc6cfd13b28e1a70341b1f","analyzedAt":"2026-08-14T23:20:02.994Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}