GJ 229 is a cool M-dwarf (about 0.51 solar masses, 3,564 K), 5.8 light-years from Earth. GJ 229 A c is a 8.6-Earth-mass planet, with an orbital period of 122 days, at 0.384 AU from its star, on an eccentric orbit (e ≈ 0.37), discovered in 2020 via radial velocity. GJ 229 b is a 14.9-Earth-mass planet, with an orbital period of 1.59 years, at 1.086 AU from its star, on an eccentric orbit (e ≈ 0.40), discovered in 2014 via radial velocity. Mutual gravitational tugs between the planets can slowly reshape their orbits, preserving clues to the system's assembly.