Facets can't @Inject Project, otherwise the following exception is thrown, which is not clear in a first moment:

Exception encountered: WELD-001303 No active contexts for scope type org.jboss.forge.shell.project.ProjectScoped (type "set VERBOSE true" to enable stack traces)

lincolnthree suggested that it might be worth adding a check for this in a validation step of the Forge 1 weld extension