diff --git a/aip/general/0216.md b/aip/general/0216.md
index 5233dfcacc..1515061ec9 100644
--- a/aip/general/0216.md
+++ b/aip/general/0216.md
@@ -123,6 +123,44 @@ message PublishBookRequest {
 - The comment for the field **should** document the resource pattern.
 - Other fields **may** be included.
 
+### Declarative-friendly state transitions
+
+If a resource's state can be modified by [declarative tooling][aip-128], it
+**should** expose a separate `desired_state` field taking the same enum type.
+
+```proto
+message Book {
+  enum State {
+    STATE_UNSPECIFIED = 0;
+    UNPUBLISHED = 1;
+    PUBLISHING = 2;
+    PUBLISHED = 3;
+  }
+  
+  State state = 1 [(google.api.field_behaviopr = OUTPUT_ONLY)];
+  State desired_state = 2;
+}
+```
+
+- The `state` field's output **may** change to more granular
+  [active states](#common-states) to indicate progress toward the `desired_state`.
+- The `desired_state` field **must** only allow [resting state](#common-states)
+  enum values.
+- Attempting to set `desired_state` to an [active state](#common-states) **must**
+  error with `INVALID_ARGUMENT` (HTTP 400).
+- Attempting to set `desired_state` to a state that cannot be transitioned to
+  from the current state **must** error with `FAILED_PRECONDITION` (HTTP 400).
+- A [long-running][] operation **must not** complete until the `state` has
+  reached the `desired_state` (or **must** error if it cannot).
+- If a resource supports both declarative `desired_state` and imperative
+  [state transition methods](#state-transition-methods), executing a state
+  transition method **should** modify the desired state appropriately.
+- If a resource is created without `desired_state`, the field **must** default
+  to the same resting value as `state`.
+- If an out-of-band event causes the resting `state` of the resource to change,
+  the `desired_state` **must** be changed to match. This does not apply to
+  a temporary condition that will return to the same resting state.
+
 ## Additional Guidance
 
 ### Default value
@@ -239,4 +277,5 @@ necessary.
 - **2019-07-18**: Added explicit guidance on the unspecified value.
 
 [aip-126]: ./0126.md
+[aip-128]: ./0128.md
 [long-running]: ./0151.md