feat(proxy): add GET /version endpoint

Per review:

- Read the version directly from litellm._version instead of importing
  proxy_server (which re-exports it); the fallback test now patches
  _version accordingly.
- Tag the route with ["public", "version"] so it groups with the other
  public endpoints in the OpenAPI docs.

litellm/proxy/_types.py

@@ -655,6 +655,7 @@ class LiteLLMRoutes(enum.Enum):
             "/public/mcp_hub",
             "/public/skill_hub",
             "/public/litellm_model_cost_map",
+            "/version",
         ]
     )
 

litellm/proxy/public_endpoints/public_endpoints.py

@@ -29,6 +29,7 @@ from litellm.types.proxy.public_endpoints.public_endpoints import (
     ProviderCreateInfo,
     PublicModelHubInfo,
     SupportedEndpointsResponse,
+    VersionResponse,
 )
 from litellm.types.utils import LlmProviders
 
@@ -287,6 +288,13 @@ async def public_skill_hub():
         raise HTTPException(status_code=500, detail=str(e))
 
 
+@router.get("/version", tags=["public", "version"], response_model=VersionResponse)
+async def version_info() -> VersionResponse:
+    from litellm._version import version
+
+    return VersionResponse(version=version)
+
+
 @router.get(
     "/public/model_hub/info",
     tags=["public", "model management"],

litellm/types/proxy/public_endpoints/public_endpoints.py

@@ -68,3 +68,7 @@ class SupportedEndpoint(BaseModel):
 
 class SupportedEndpointsResponse(BaseModel):
     endpoints: List[SupportedEndpoint]
+
+
+class VersionResponse(BaseModel):
+    version: str

tests/test_litellm/proxy/auth/test_user_api_key_auth.py

@@ -86,6 +86,7 @@ def test_public_ai_hub_routes_remain_public():
         "/public/agent_hub",
         "/public/mcp_hub",
         "/public/skill_hub",
+        "/version",
     ):
         assert route in LiteLLMRoutes.public_routes.value
         assert _route_requires_auth_despite_public(route, {}) is False

tests/test_litellm/proxy/public_endpoints/test_public_endpoints.py

@@ -91,6 +91,40 @@ def test_get_litellm_model_cost_map_returns_cost_map():
     )
 
 
+def test_version_endpoint():
+    import litellm._version as _ver
+
+    app = FastAPI()
+    app.include_router(router)
+    client = TestClient(app)
+
+    response = client.get("/version")
+
+    assert response.status_code == 200
+    body = response.json()
+    assert isinstance(body, dict)
+    assert "version" in body
+    assert isinstance(body["version"], str)
+    assert body["version"] == _ver.version
+
+
+@pytest.mark.parametrize("fake_version", ["unknown", "0.0.0"])
+def test_version_endpoint_fallback_strings_still_return_200(fake_version: str):
+    import litellm._version as _ver
+
+    app = FastAPI()
+    app.include_router(router)
+    client = TestClient(app)
+
+    with patch.object(_ver, "version", fake_version):
+        response = client.get("/version")
+
+    assert response.status_code == 200
+    body = response.json()
+    assert body["version"] == fake_version
+    assert isinstance(body["version"], str)
+
+
 def test_public_ai_hub_info_is_public_by_default(monkeypatch):
     app = FastAPI()
     app.include_router(router)