diff --git a/mjx/mujoco/mjx/_src/types.py b/mjx/mujoco/mjx/_src/types.py
index b0be4743..961f32a2 100644
--- a/mjx/mujoco/mjx/_src/types.py
+++ b/mjx/mujoco/mjx/_src/types.py
@@ -170,6 +170,7 @@ class SolverType(enum.IntEnum):
 
   Members:
     CG: Conjugate gradient (primal)
+    NEWTON: Newton (primal)
   """
   # unsupported: PGS
   CG = mujoco.mjtSolver.mjSOL_CG