specify init hangs on select_with_arrows prompts in non-interactive environments — no flag reaches them, --force does not bypass them

[victor-bogdan]

Summary

When specify init is run in an environment without an interactive TTY (an AI agent harness, CI, or any piped/captured stdin), initialization can hang indefinitely at an arrow-key selection prompt (select_with_arrows). The prompt waits for keypresses that will never arrive, renders nothing useful to the caller, and never times out.

The existing CLI flags do not cover this:

• --script and other explicit option flags (--here, --integration, --ai) pre-answer their own questions, but any selection not covered by a flag still falls through to select_with_arrows — there is no flag that reaches every prompt.
• --force suggests "proceed without asking", but it only suppresses confirmation-style prompts; it does not provide a default answer to selection prompts, so the hang is unreachable by --force too.
• There is no global --non-interactive / --defaults mode, and no TTY detection: with stdin not a TTY, the tool still enters the interactive selector instead of failing fast.

Reproduction

1. Run specify init --here --integration claude --force (or any invocation that leaves at least one selection unanswered by flags) with stdin/stdout not attached to a TTY — e.g. piped, under CI, or driven by an agent harness.
2. Initialization reaches the first selection that has no corresponding flag and blocks in select_with_arrows waiting for arrow-key input.
3. No timeout, no error, no output indicating what is being asked — from the caller's side the process simply hangs.

Expected behavior (any of these would resolve it)

1. Fail fast when non-interactive: if stdin is not a TTY and a selection has no flag-supplied answer, exit with a clear error naming the missing option and the flag that would supply it — instead of blocking on keyboard input.
2. A --non-interactive (or --defaults) mode that answers every selection with its documented default, and errors loudly on any selection that has no safe default.
3. Flag coverage for every select_with_arrows prompt, so a fully scripted init is expressible — at which point --force + explicit flags genuinely means "no prompts".

Why it matters

Spec Kit is a natural fit for agent-driven workflows, and those are precisely the environments with no TTY. Today a scripted specify init is not reliably expressible: whether it completes depends on whether the chosen flag combination happens to pre-answer every prompt, and when it doesn't, the failure mode is a silent hang rather than an actionable error.

Environment

• specify 0.16.3.dev0
• Invoked non-interactively (AI agent harness; stdin not a TTY)
• Workaround used: ran the interactive selection out-of-band and supplied every flag the CLI exposes; the remaining prompt(s) had to be avoided rather than answered.