I provided this link previously:

https://dor.wa.gov/taxes-rates/other-taxes/capital-gains-tax/do-you-owe-capital-gains-tax

Did you report LTCG to the Feds? If so, the type of asset and your status for being a WA resident are taken into consideration; then the amount after evaluating for the exemptions, would be analyzed.

Then, if you, the individual, owes, you would file. If you, the individual, do not owe, you don't need to file. There is no generic reporting requirement. Only a filing requirement, if you owe.