Work of all kinds increasingly takes place via networked digital environments that support diverse modes of collaboration. Previous work has investigated how collaborative writing takes place in shared and open workspaces. This study investigates how the "fork-and-pull'' model of distributed version management, now widely utilized in software development, supports coordination and public contribution in collaborative writing. We employ a case study approach to understand coordination around written artifacts in an open pull-based environment. Through interviews and archival analysis of two open text projects: a mathematics textbook on homotopy type theory (HoTT) and open source policies by 18F, a branch of federal agency, we reconstruct how text artifacts were created. We find that in both cases an intensive multi-channel communication among a small core preceded an explicit release action in the form of public communication to solicit broader contribution. Our analysis reveals a dichotomy between two modes of collaboration: a perfecting mode of crafting a public written document versus an evolution mode. In perfecting, authors used the fork-and-pull model to manage contributions refining the text to a more correct version. In evolution, authors used the fork-and-pull model to use a written artifact as a template and starting point, customizing it to their relevant scope. Based on our results, we consider how we might design systems and policies to support pull-based coordination around written artifacts and the forms it takes.