19548 jenkins: add user agent to session headers

Adding a user agent header enables administrators to easily identify
requests originating from Checkmk in Jenkins access logs or network
monitoring tools. This will hopefully simplify monitoring and
troubleshooting.

The content of the user agent was intentionally done in this way so that
it will pass the plugin consistency tests.

CMK-32813

Change-Id: Ief3ebf00b9549aab0770142cf308883cd8c23c45

Author: logan-connolly

.werks/19548.md

@@ -0,0 +1,22 @@
+[//]: # (werk v3)
+# Jenkins: add User-Agent HTTP header to special agent
+
+key        | value
+---------- | ---
+date       | 2026-03-24T12:32:16.794953+00:00
+version    | 2.5.0b5
+class      | feature
+edition    | community
+component  | checks
+level      | 1
+compatible | yes
+
+The Jenkins special agent now specifies the HTTP "User-Agent" header as
+`User-Agent: checkmk-special-jenkins-{version}`. The `version` variable here
+denotes which version of Checkmk is running.
+
+This allows administrators to easily identify the agent in their access logs or
+network monitoring tools, simplifying the monitoring and troubleshooting of
+these inbound requests.
+
+No user configuration is required for this change.

cmk/plugins/jenkins/special_agent/agent_jenkins.py

@@ -24,7 +24,7 @@
 __version__ = "2.5.0b5"
 
 AGENT = "jenkins"
-
+USER_AGENT = f"checkmk-special-{AGENT}-{__version__}"
 PASSWORD_OPTION = "secret"
 
 
@@ -143,6 +143,7 @@ def handle_request(args, sections):
     # labels = {}
 
     session = requests.Session()
+    session.headers.update({"User-Agent": USER_AGENT})
     session.auth = (args.user, resolve_secret_option(args, PASSWORD_OPTION).reveal())
 
     for section in sections: