Quick addition to that - that's very true if you're working with the GPLv3 and putting your code back into the public domain, but bear in mind that it's not true if you want to subsequently sell the Agent under any other license. Sorry to be a license bore, just don't want anyone to make that mistake and live to regret it, it's easily done and very tedious in the event (re-implementing a pile of code from scratch when one has already used a perfectly good GPL version of the same code is one of life's less inspiring activities).
With that proviso, go ahead and copy them to your hearts content. No point in reinventing the wheel.
John