[Rachael]

That code won't work

pawn Код:

result = strtok(cmdtext, idx);

strtok will return the next word separated by a space ( not the whole line )

pawn Код:

if(!strlen(strval(result)))

is incorrect, strval returns an integer

also, you have %s in the format, and you are formatting an integer.
you have defined str[128] and then used string
try this

pawn Код:

if(!strcmp(cmd, "/admin", true) || !strcmp(cmd, "/a", true))
{
    if(PlayerInfo[playerid][pAdmin] >= 1)
    {
        new result[128], str[128], sendername[MAX_PLAYER_NAME];
        strmid(result,cmdtext,idx,strlen(cmdtext),sizeof(result));
        if(!strlen(result)) return SendClientMessage(playerid, COLOR_GRAD2, "USAGE: (/a)dmin [admin chat]");
    
        GetPlayerName(playerid,sendername,sizeof(sendername));
        format(str, sizeof(str), "*%d Admin %s: %s", PlayerInfo[playerid][pAdmin], sendername, result);
        SendAdminMessage(COLOR_YELLOW, str);
        return 1;
    }
    SendClientMessage(playerid,COLOR_GRAD2,"Unauthorized command");
    return 1;
}

In this instance, idx will already hold the reference for the start of the 'chat' portion of cmdtext