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ADR-0018 — Zed editor: investigated, rejected for now

  • Status: Rejected (for now, 2026-06) — design shovel-ready if revisited
  • Sources: docs/history/agent-editor-plugins-plan.md Item 4a

Context

The editor plugins needed a second editor beside VS Code, and Zed was the obvious candidate. The question was the remote transport: how does a Mac-side editor reach a dev box that, by design, holds no ~/.ssh and accepts no inbound credential?

VS Code answers it without SSH: the Remote-Containers extension talks to the container engine API over the mounted socket (DOCKER_HOST), execs into the running box, runs the VS Code Server there, and streams over the exec stdio — no sshd, no network port, no inbound credential. That is exactly why fy code is a Mac-side verb that only needs the socket env, and why VS Code rides the same rootless-socket trust boundary as everything else.

Zed was investigated against its official docs and source. Zed remote development is SSH-only: the local Zed shells out to the system ssh binary, establishes a ControlMaster, and uploads and runs a zed-remote-server binary in ~/.zed_server on the remote (upload_binary_over_ssh: true for restricted-internet remotes — which the box is). There is no container-engine-exec transport.

Decision

Skip Zed for now. Supporting it means running sshd inside the box — host keys, authorized_keys, an inbound auth surface — on a box whose design deliberately keeps no ~/.ssh and no inbound credential. That inversion of the box's credential posture is not worth a second editor while VS Code covers the need over the engine socket.

The least-bad design was worked out and recorded as shovel-ready, should demand return: sshd -i (inetd mode, one session on stdin/stdout, no listener, no published port) behind an ~/.ssh/config ProxyCommand podman exec -i <box> … — Zed honours ssh_config since it shells out to ssh. That reuses the same engine-socket trust boundary as VS Code, mounts only the Mac's public key, and puts nothing on the VM's network. It is strictly better than publishing port 22, but still adds the sshd surface and stayed unbuilt.

Consequences

  • VS Code is the supported attach editor (server volume + engine-exec attach, fy code); the vscode plugin ships in core, inert until [vscode] is declared (ADR-0015).
  • No [zed] plugin, no sshd, no host keys in the box image or bootstrap — the no-inbound-creds property stays absolute rather than "except for the editor".
  • What would change the call: Zed shipping a non-SSH remote transport (a container/engine-exec mode, or any stdio transport foldyard can supply without sshd). Short of that, a recurring user need would revive the ProxyCommand + sshd -i design above, gated behind an opt-in [zed] table with the key material kept to the public half.