Closing stdin alone only suppresses the prompt branch; a saved
`plan_tune_hooks: yes` or exported GSTACK_PLAN_TUNE_HOOKS=yes would still
resolve to "install" and rewrite the user's global ~/.claude/settings.json to
point at THIS ephemeral worktree — which breaks once the workspace is deleted.
Pass --plan-tune-hooks=prompt (highest precedence) so dev-setup pins resolution
to prompt-mode; with stdin closed that is a guaranteed no-op skip (no install,
no decline marker). To install the hooks, run ./setup --plan-tune-hooks directly.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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