The first step for allowing local reasoning is to break your product into independent subdomains that are as independent as possible. For a software company,

The first step for allowing local reasoning is to break your product into independent subdomains that are as independent as possible. For a software company, this means crafting the product ownership of your team such that the teams can act as independently as possible. This is where most companies already fail. Once this has been achieved, you can follow this pattern on smaller and smaller scales down to individual functions in your code.