The README names what the project covers and where it runs
A reader’s first question is whether they are in the audience at all. A README that describes what the project does but never names the forges, registries, runtimes, or platforms it supports makes every reader run the install command to find out, and most of them will not.
Observable check
README.md names the platforms, forges, ecosystems, registries, or runtimes the project supports, and each name it claims appears in the source, the manifest, or the CI configuration.
Where this comes from
No upstream source. This is oss-kit's own position, and the argument for it is below.
Upstream good-readme asks the opening block what the project does and never asks for its boundary, and no README specification asks either. Observed while writing facts lists: the scope bullet is the one most often missing, because a boundary lives in configuration and reference files rather than in the code an author is proud of, and it is the bullet that lets a reader rule themselves out before installing anything. Retire this rule if the supported-platforms question is ever answered by a manifest field that forges render.