diff --git a/docs/google/devices.md b/docs/google/devices.md
index 4784dc65cc5..d1a237424e8 100644
--- a/docs/google/devices.md
+++ b/docs/google/devices.md
@@ -231,9 +231,13 @@ Circuits with a repetitive structure can benefit from using
 Using this type condenses the serialized representation of the circuit, which
 may help for circuits that would otherwise run into size limitations.
 
+### Parameterized Gates
 
-## Specific Device Layouts
+Circuits for Google devices could contain gates parameterized by Sympy
+expressions, but only a subset of Sympy expression types are supported:
+`sympy.Symbol`, `sympy.Add`, `sympy.Mul`, and `sympy.Pow`.
 
+## Specific Device Layouts
 The following devices are provided as part of cirq and can help you get your
 circuit ready for running on hardware by verifying that you are using
 appropriate qubits.