A simple vscript for finding and editing weapons based on their Item Definition in TF2.

tf2_weaponEdit.nut

function processWeapon( weapon ) {
    //ref: https://wiki.alliedmods.net/Team_fortress_2_item_definition_indexes
    //ref: https://wiki.teamfortress.com/wiki/List_of_item_attributes
    local itemIndex = NetProps.GetPropInt(weapon, "m_AttributeManager.m_Item.m_iItemDefinitionIndex");
    if ( itemIndex == 40 ) {
        weapon.AddAttribute("airblast cost decreased", 0.4, -1)
    }
}

function OnGameEvent_post_inventory_application(p) {
    local ply = GetPlayerFromUserID(p.userid)
    if ( !ply ) { return; }

    for ( local i = 0; i < 7; i++ ) {
        local wep = NetProps.GetPropEntityArray(ply, "m_hMyWeapons", i)
        if ( wep != null ) {
            processWeapon(wep)
        }
    }
}

__CollectGameEventCallbacks(this);