This gets back to our age-old yakking about how to define net worth. Under the standard definition of net worth (assets-liabilities), you would calculate the net present value of the annuity and add that to your other assets.
But, from previous discussions, we have learned that many among us are actually interested in something else. They come up with some new compilation, maybe subtracting house value, and they call this their definition of net worth. Often this is synonymous with the illusive portfolio "number" that everyone seeks to define for calculating how long they can survive. From OP's use of the 4% rule, I suspect he may be trying to figure out a pension's value in calculating this number.
Others have pointed out that the 4% rule is OK if you are single or have a 100% survivor continuation if married. I would add that is only useful to the extent the pension will keep up with inflation, like Social Security does. If not, you need some adjustments.
Edit: At the top I said you could add the net present value, but I don't think that is correct. For a traditional net worth valuation, only what you would have if you made a final reconning today (i.e., died) would figure into net worth. So, if the annuity had a 10 year guarantee you could add that, but the amount would decline every year.