open-pstack — one skill tree, two parent harnesses, a runner for every other provider Diagram

One shared skill tree

Claude Code and Codex read the same plugins/pstack/skills
harness names resolve through codex-tools.md; models through provider-dispatch.md

The parent routes, children never do

same provider: the parent's own subagent primitive
every other provider: pstack-runner, one model call, a receipt

A dropout is not a fallback

missing CLI, login, model or proof ends the lane with a named status
no weaker model, no other provider, no implicit timeout