When using carbon steel for tool making you are faced with the decision whether to use high carbon steel that can be hardened properly and will keep an edge for a long time, but is quite brittle after hardening, or better use low carbon steel that can't be hardened and will get blunt very soon, but is more flexible so it doesn't break either.
Any compromise in carbon content will be a compromise in performance also, medium carbon steel will be better than high carbon steel re flexibility but worse re edge holding properties.
One way to work around this problem is to compose your tool from different steels, the high carbon steel used for the parts that will provide the cutting edge and low carbon steel to coat it and give it strength and flexibility.
https://www.youtube.com/watch?v=LjlcqQVN6io