Returns true when a user message explicitly @-mentions the given agent (by JSON mention token @{..."id":"<agentId>"...}, JSON token @{..."name":"<agentName>"...}, or plain @<agentName>).
@
@{..."id":"<agentId>"...}
@{..."name":"<agentName>"...}
@<agentName>
Optional
Returns true when a user message explicitly
@-mentions the given agent (by JSON mention token@{..."id":"<agentId>"...}, JSON token@{..."name":"<agentName>"...}, or plain@<agentName>).