BerriAI/litellm · error · ValueError

LAR-1 thresholds must satisfy 0 < low < medium < high < 1, g

Error message

LAR-1 thresholds must satisfy 0 < low < medium < high < 1, got low={low}, medium={medium}, high={high}

What it means

Config validation in LAR-1 routing: the low/medium/high latency thresholds merged from routing_strategy_args must be strictly increasing within (0,1); the supplied values violate that ordering, so the strategy cannot bucket latencies.

Source

Thrown at litellm/router_strategy/lar1_routing.py:62

def apply_lar1_routing_strategy(
    router: Router,
    routing_strategy_args: Mapping[str, object] | None = None,
) -> None:
    strategy: Final = LAR1RoutingStrategy(
        router_instance=router,
        thresholds=lar1_thresholds_from_args(routing_strategy_args),
    )
    router.routing_strategy = "lar1"
    router.set_custom_routing_strategy(strategy)


def _normalize_thresholds(thresholds: dict[str, float] | None) -> dict[str, float]:
    merged: Final = {**DEFAULT_THRESHOLDS, **(thresholds or {})}
    low: Final = merged["low"]
    medium: Final = merged["medium"]
    high: Final = merged["high"]
    if not (0 < low < medium < high < 1):
        raise ValueError(
            f"LAR-1 thresholds must satisfy 0 < low < medium < high < 1, got low={low}, medium={medium}, high={high}"
        )
    return merged


def _parse_lar1_metadata(request_kwargs: dict) -> LAR1Metadata:
    lar1_raw: Final = request_kwargs.get("metadata", {}).get("lar1", {})
    if not isinstance(lar1_raw, dict):
        verbose_router_logger.warning("[LAR-1] Invalid lar1 metadata type: %s. Using defaults", type(lar1_raw).__name__)
        return LAR1Metadata()
    try:
        return LAR1Metadata.model_validate(lar1_raw)
    except ValidationError as exc:
        verbose_router_logger.warning("[LAR-1] Invalid lar1 metadata: %s. Using defaults", exc)
        return LAR1Metadata()


class LAR1RoutingStrategy(CustomRoutingStrategyBase):

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Adjust LAR-1 thresholds so 0 < low < medium < high < 1.

When it happens

Trigger: Thrown at litellm/router_strategy/lar1_routing.py:62 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/8c2c9c12295c5202. Report an issue: GitHub.