BerriAI/litellm · error · ValueError

No router config provided

Error message

No router config provided

What it means

Guard in AutoRouter init/_load_semantic_routing_routes: neither auto_router_config_path nor auto_router_config was supplied, so no semantic routes can be loaded and the router cannot classify requests.

Source

Thrown at litellm/router_strategy/auto_router/auto_router.py:71

        self.auto_router_config_path: str | None = auto_router_config_path
        self.auto_router_config: str | None = auto_router_config
        self.auto_sync_value = self.DEFAULT_AUTO_SYNC_VALUE
        self.loaded_routes: list[Route] = self._load_semantic_routing_routes()
        self.routelayer: SemanticRouter | None = None
        self.default_model = default_model
        self.embedding_model: str = embedding_model
        self.max_input_chars: int = max_input_chars
        self.litellm_router_instance: Router = litellm_router_instance

    def _load_semantic_routing_routes(self) -> list[Route]:
        from semantic_router.routers import SemanticRouter

        if self.auto_router_config_path:
            return SemanticRouter.from_json(self.auto_router_config_path).routes
        elif self.auto_router_config:
            return self._load_auto_router_routes_from_config_json()
        else:
            raise ValueError("No router config provided")

    def _load_auto_router_routes_from_config_json(self) -> list[Route]:
        import json

        from semantic_router.routers.base import Route

        if self.auto_router_config is None:
            raise ValueError("No auto router config provided")
        auto_router_routes: Final[list[Route]] = []
        loaded_config: Final = json.loads(self.auto_router_config)
        for route in loaded_config.get("routes", []):
            auto_router_routes.append(
                Route(
                    name=route.get("name"),
                    description=route.get("description"),
                    utterances=route.get("utterances", []),
                    score_threshold=route.get("score_threshold"),
                )

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Provide a router config to the auto router constructor.

When it happens

Trigger: Thrown at litellm/router_strategy/auto_router/auto_router.py:71 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/c7bcf37ba4e5a415. Report an issue: GitHub.