{"record":{"id":"7fff861e2afe2573","repo":"BerriAI/litellm","slug":"adaptive-true-requires-at-least-one-non-empty-tier","errorCode":null,"errorMessage":"adaptive=True requires at least one non-empty tier pool","messagePattern":"adaptive=True requires at least one non-empty tier pool","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"litellm/router_strategy/complexity_router/config.py","lineNumber":642,"sourceCode":"    @classmethod\n    def _normalize_escalation_keywords(cls, value: list[str] | None) -> list[str] | None:\n        if value is None:\n            return None\n        return [stripped for keyword in value if (stripped := keyword.strip())]\n\n    @model_validator(mode=\"after\")\n    def _validate_llm_classifier_config(self) -> \"ComplexityRouterConfig\":\n        if self.classifier_type == \"llm\" and self.classifier_llm_config is None:\n            raise ValueError(\"classifier_llm_config is required when classifier_type is 'llm'\")\n        return self\n\n    @model_validator(mode=\"after\")\n    def _validate_adaptive_pools(self) -> \"ComplexityRouterConfig\":\n        if not self.adaptive:\n            return self\n        normalized = {tier: (models if isinstance(models, list) else [models]) for tier, models in self.tiers.items()}\n        if not any(normalized.values()):\n            raise ValueError(\"adaptive=True requires at least one non-empty tier pool\")\n        empty: Final = [tier for tier, models in normalized.items() if not models]\n        if empty:\n            raise ValueError(f\"adaptive=True tier pools must be non-empty; empty tiers: {empty}\")\n        self.tiers = normalized\n        return self\n\n    @model_validator(mode=\"after\")\n    def _validate_semantic_matching(self) -> \"ComplexityRouterConfig\":\n        if not self.semantic_keyword_matching:\n            return self\n        if not self.embedding_model:\n            raise ValueError(\"embedding_model is required when semantic_keyword_matching is enabled\")\n        if not self.keyword_tier_rules:\n            raise ValueError(\"keyword_tier_rules must be non-empty when semantic_keyword_matching is enabled\")\n        return self\n\n    @model_validator(mode=\"after\")\n    def _validate_tier_labels(self) -> \"ComplexityRouterConfig\":","sourceCodeStart":624,"sourceCodeEnd":660,"githubUrl":"https://github.com/BerriAI/litellm/blob/77b7c6c40c0c5aa5fbcb1d6a1825ac39ca8829b8/litellm/router_strategy/complexity_router/config.py#L624-L660","documentation":"Config validator on ComplexityRouterConfig: adaptive mode is enabled, but after normalizing tier pools every tier is empty — the bandit has no models to sample, so the config is rejected.","triggerScenarios":"Thrown at litellm/router_strategy/complexity_router/config.py:642 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Provide at least one non-empty tier pool, or disable adaptive."],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"77b7c6c40c0c5aa5fbcb1d6a1825ac39ca8829b8","analyzedAt":"2026-08-18T11:44:31.656Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}