Stance: Open Shell in D, Nushell as reference

What changed

We do ship a structured shell: Open Shell in Dlang.

We do not claim Nushell is wrong — it proved the model. Upstream Nu remains the reference for nu compatibility mode and for users who want vanilla Nushell.

The old one-liner do not reinvent Nushell meant do not silently duplicate without cause. Cause arrived: context chrome, overlay layers, control plane, and a default syntax mode we can evolve.

What we will do

  • Ship openshellorg/open-shell — default oso mode + compatibility modes (nu, bash, …)

  • Reproduce Nushell behavior in D for nu mode baseline (parity tests), not as the default UX

  • Advocate structured pipelines in docs; credit PowerShell history, Nushell as reference implementation

  • Build companion libraries (nu-require, shell-context, nu-emit, …) — usable from any mode where applicable

  • Contribute upstream when a fix helps everyone and is not OSO-specific chrome

What we will not do

  • Imply prohelp requires Open Shell (see naming note)

  • Pretend bash mode covers zsh/fish/oil on day one — add modes explicitly

  • Shell out to nu binary as the primary execution strategy