{"record":{"id":"7ac878a8f475b3d6","repo":"langchain-ai/langgraph","slug":"unknown-operation-type-type-op","errorCode":null,"errorMessage":"Unknown operation type: {type(op)}","messagePattern":"Unknown operation type: (.+?)","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"libs/checkpoint/langgraph/checkpoint/store/memory/__init__.py","lineNumber":400,"sourceCode":"            elif isinstance(op, ListNamespacesOp):\n                results.append(self._handle_list_namespaces(op))\n            elif isinstance(op, PutOp):\n                put_ops[(op.namespace, op.key)] = op\n                results.append(None)\n            else:\n                raise ValueError(f\"Unknown operation type: {type(op)}\")\n\n        return results, put_ops, search_ops","sourceCodeStart":null,"sourceCodeEnd":null,"githubUrl":"https://github.com/langchain-ai/langgraph/blob/38031739e551638e373fb553453256c23feeb41f/libs/checkpoint/langgraph/checkpoint/store/memory/__init__.py#L400","documentation":"Dispatch guard in InMemoryStore.batch: while sorting queued Ops, an object that is not one of the known operation types (GetOp, SearchOp, ListNamespacesOp, PutOp) reached the router. Ops are typed dataclasses; passing a raw tuple, a string, or a custom op class (e.g. from a mismatched langgraph-checkpoint version) triggers this error.","triggerScenarios":"Thrown at libs/checkpoint/langgraph/checkpoint/store/memory/__init__.py:400 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Use the typed Op dataclasses (PutOp, GetOp, SearchOp, ListNamespacesOp) from langgraph.store.base when calling batch directly","Prefer the high-level put/get/search methods which construct ops for you","Ensure all packages import Ops from the same installed langgraph-checkpoint version"],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"38031739e551638e373fb553453256c23feeb41f","analyzedAt":"2026-08-26T18:02:49.312Z","contentChangedAt":"2026-08-26T18:02:49.312Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}