diff --git a/docs/xacml/decision-api.rst b/docs/xacml/decision-api.rst
index 7d068c1..8f6a993 100644
--- a/docs/xacml/decision-api.rst
+++ b/docs/xacml/decision-api.rst
@@ -9,6 +9,10 @@
 specific situation. The Decision API mimics closely the XACML request standard in that it supports a subject, action
 and resource.
 
+When the PAP activates an xacml-pdp, the decision API becomes available. Conversely, when the PAP deactivates an xacml-pdp, the
+decision API is disabled. The decision API is enabled/disabled by the PDP-STATE-CHANGE messages from PAP. If a request is made
+to the decision API while it is deactivated, a "404 - Not Found" error will be returned.
+
 .. csv-table::
    :header: "Field", "Required", "XACML equivalent", "Description"