diff --git a/README.md b/README.md
index de66089b2c9903e1302f52b01d580506647e111f..13b2a443f8ba30456b50152419deac9410b33ebb 100644
--- a/README.md
+++ b/README.md
@@ -94,6 +94,45 @@ The plugin creates the service **_RADIUS_** with an optional item.
 
 </details>
 
+<details><summary>Active check CLI usage</summary>
+
+```
+OMD[build]:~$ ~/local/lib/nagios/plugins/check_radius -h
+usage: check_radius [-h] -H HOST --secret SECRET [--username USERNAME] [--password PASSWORD] [--auth-port AUTH_PORT] [--timeout TIMEOUT] [--request-attribute [REQUEST_ATTRIBUTE ...]] [--expected-response {2,3}] [--state-not-expected-response {0,1,2,3}] [--num-resp-attributes NUM_RESP_ATTRIBUTES]
+                    [--state-wrong-num-resp-attributes {0,1,2,3}] [--max-response-time MAX_RESPONSE_TIME]
+
+This is a (very) basic active RADIUS check for Check_mk. 
+Tests if a RADIUS server is responsive (accept/reject/timeout). There is (limited) support to add AV-pairs to the RADIUS request.
+
+options:
+  -h, --help            show this help message and exit
+  -H HOST, --host HOST  Host/IP-Address of RADIUS server to query (required) (default: None)
+  --secret SECRET       secret RADIUS key (default: None)
+  --username USERNAME   user name to test with (default: dummyuser)
+  --password PASSWORD   user password to test with (default: dummypassword)
+  --auth-port AUTH_PORT
+                        RADIUS authentication port to use. (default: 1812)
+  --timeout TIMEOUT     RADIUS server timeout (default: 1)
+  --request-attribute [REQUEST_ATTRIBUTE ...]
+                        add request attribute in the form of "attribute-name:attribute-value" ie: "Called-Station-Id:AA-BB-CC-DD-EE-FF".
+                        Repeat to add more attributes. For valid attributes the dictionary file. (default: [])
+  --expected-response {2,3}
+                        2 -> Accepted, 3 -> Rejected (default: None)
+  --state-not-expected-response {0,1,2,3}
+                        Monitoring state: 0 -> OK, 1 -> WARN, 2 -> CRIT, 3 -> UNKNOWN (default: 1)
+  --num-resp-attributes NUM_RESP_ATTRIBUTES
+                        Expected number of response attributes (default: None)
+  --state-wrong-num-resp-attributes {0,1,2,3}
+                        Monitoring state: 0 -> OK, 1 -> WARN, 2 -> CRIT, 3 -> UNKNOWN (default: 1)
+  --max-response-time MAX_RESPONSE_TIME
+                        Upper levels for response time in ms in the format WARN,CRIT time. ie: 10,50 (default: None)
+
+(c) thl-cmk[at]outlook[dot], Version: 0.1.1-20240428, For more information see: https://thl-cmk.hopto.org
+
+
+```
+</details>
+
 ---
 ### Sample Output