From 828228e0d2894d2b3f2091dc00d9aab9cf9fe9ee Mon Sep 17 00:00:00 2001
From: Tanishq <74068132+tanishqbaweja@users.noreply.github.com>
Date: Mon, 26 Oct 2026 00:45:06 +0530
Subject: [PATCH] fix(router): normalize numeric deployment weights

---
 litellm/types/router.py                       |  1 +
 tests/unit/types/test_router.py               | 38 ++++++++++++++++++-
 ui/litellm-dashboard/src/lib/http/schema.d.ts |  4 ++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/litellm/types/router.py b/litellm/types/router.py
index cd1389aea9d..8599feb5731 100644
--- a/litellm/types/router.py
+++ b/litellm/types/router.py
@@ -533,6 +533,7 @@ class GenericLiteLLMParams(CredentialLiteLLMParams, CustomPricingLiteLLMParams):
     rpm: int | None = None
     itpm: int | None = None
     otpm: int | None = None
+    weight: float | None = None
     timeout: float | str | httpx.Timeout | SDKTimeout | None = None  # if str, pass in as os.environ/
     # read timeout of a live stream, a faked stream takes the longer of this and timeout. If str, pass in as os.environ/
     stream_timeout: float | str | None = None
diff --git a/tests/unit/types/test_router.py b/tests/unit/types/test_router.py
index 2892a829eab..ea481768626 100644
--- a/tests/unit/types/test_router.py
+++ b/tests/unit/types/test_router.py
@@ -1,11 +1,12 @@
 import logging
-from typing import Final
+from typing import Final, Literal
 
 import httpx
 import pytest
 from openai import Timeout as SDKTimeout
 from pydantic import ValidationError
 
+from litellm.router_strategy.simple_shuffle import simple_shuffle
 from litellm.types.router import (
     SPECIAL_MODEL_INFO_PARAMS,
     CredentialLiteLLMParams,
@@ -37,6 +38,41 @@ def test_sdk_timeout_is_normalized_for_provider_clients() -> None:
     assert params.timeout.as_dict() == timeout.as_dict()
 
 
+@pytest.mark.parametrize(
+    "parameter, preferred, zero",
+    [
+        ("weight", "1.5", "0"),
+        ("weight", "100", 0),
+        ("weight", 100, "0"),
+        ("weight", 1.5, 0),
+        ("rpm", "100", "0"),
+        ("tpm", "100", "0"),
+    ],
+)
+def test_numeric_string_routing_params_select_the_nonzero_deployment(
+    parameter: Literal["weight", "rpm", "tpm"], preferred: str | float, zero: str | int
+) -> None:
+    deployments: Final = tuple(
+        {"litellm_params": GenericLiteLLMParams(**{parameter: value}).model_dump(exclude_none=True)}
+        for value in (preferred, zero)
+    )
+
+    assert simple_shuffle(lambda _: None, deployments, "weighted-model", None) is deployments[0]
+
+
+def test_none_weight_keeps_rate_based_routing() -> None:
+    deployments: Final = tuple(
+        {"litellm_params": GenericLiteLLMParams(weight=None, rpm=rpm).model_dump(exclude_none=True)} for rpm in (100, 0)
+    )
+
+    assert simple_shuffle(lambda _: None, deployments, "weighted-model", None) is deployments[0]
+
+
+def test_invalid_deployment_weight_is_rejected_before_routing() -> None:
+    with pytest.raises(ValidationError, match="weight"):
+        GenericLiteLLMParams(weight="heavy")
+
+
 def test_model_info_declares_mirrored_pricing_fields():
     """The pricing keys Deployment mirrors onto model_info must be declared fields, not
     extras that only survive because ModelInfo sets extra="allow"."""
diff --git a/ui/litellm-dashboard/src/lib/http/schema.d.ts b/ui/litellm-dashboard/src/lib/http/schema.d.ts
index 262e8b6deae..366176a1e0d 100644
--- a/ui/litellm-dashboard/src/lib/http/schema.d.ts
+++ b/ui/litellm-dashboard/src/lib/http/schema.d.ts
@@ -35673,6 +35673,8 @@ export interface components {
             vertex_project?: string | null;
             /** Watsonx Region Name */
             watsonx_region_name?: string | null;
+            /** Weight */
+            weight?: number | null;
         } & {
             [key: string]: unknown;
         };
@@ -51024,6 +51026,8 @@ export interface components {
             vertex_project?: string | null;
             /** Watsonx Region Name */
             watsonx_region_name?: string | null;
+            /** Weight */
+            weight?: number | null;
         } & {
             [key: string]: unknown;
         };