# Issue #804 — fail closed on unknown installer arguments

## Objective

Implement Part 1 of Gitea issue #804 only: `tools/install.sh` must reject every unrecognized flag or argument with an actionable STDERR error and nonzero exit before installation starts.

## Scope and constraints

- Preserve all currently recognized options and behavior, including `-y` and `--ref <branch>`.
- No positional arguments are currently accepted by the parser.
- Do not add `--next`, `MOSAIC_NEXT`, prerelease routing, or any Part 2 behavior.
- TDD is mandatory: add and observe a failing process-level regression test before changing `tools/install.sh`.
- Worker lifecycle ends after branch push, PR creation, and coordinator notification; do not merge or close #804.
- Existing launcher-owned changes in `.mosaic/orchestrator/mission.json` and `.mosaic/orchestrator/session.lock` are out of scope and must not be committed.

## Requirements and acceptance criteria

- Unknown input names the offending argument on STDERR.
- STDERR includes a short installer usage hint.
- Exit status is nonzero.
- The installer does not invoke npm or otherwise proceed into installation.
- Existing recognized flags remain unchanged.

## Plan

1. Add a process-level Vitest regression using the installer test location under `packages/mosaic/src/commands/`.
2. Run the focused test and record the expected RED failure.
3. Commit the RED test as `test(#804): ...`.
4. Replace the parser catch-all with a fail-closed STDERR error and usage hint.
5. Update concise installer-facing documentation without introducing prerelease behavior.
6. Run focused tests, shell syntax validation, package tests, lint, typecheck, and format checks.
7. Run independent review tooling and remediate findings.
8. Commit as `fix(#804): ...`, queue-guard, push, open a PR containing `Closes #804.`, notify the coordinator, and exit.

## Budget

- No explicit token cap supplied.
- Working estimate: 8K tokens; narrow two-file behavior/test change plus concise docs and delivery gates.

## Progress

- 2026-07-17: Loaded mission state, issue #804, delivery/QA/documentation rails, and relevant TDD/Vitest/pnpm/Gitea skills.
- 2026-07-17: Confirmed the parser has no legitimate positional arguments and currently drops all unmatched input via `*) shift ;;`.
- 2026-07-17: Installed locked workspace dependencies with a worktree-local pnpm store; no lockfile changes.
- 2026-07-17: Added the process-level unknown-argument regression with an isolated `$HOME` and npm shim.
- 2026-07-17: Replaced the silent catch-all with STDERR error + usage output and exit 2 before preflight or installation.
- 2026-07-17: Initial Codex code review found an unknown option could still be consumed as the `--ref` value. Added a second RED reproducer, then rejected option-shaped/missing `--ref` values without changing valid `--ref <branch>` behavior. The review's launcher-state note is handled by excluding both `.mosaic/orchestrator/` files from commits.
- 2026-07-17: Updated README, user guide, and packaged framework README with the fail-closed argument contract. No API, auth, admin, sitemap/navigation, or publishing surface changed.

## Verification

- RED: `pnpm --filter @mosaicstack/mosaic exec vitest run src/commands/install-arguments.spec.ts` — expected failure: installer exited `0` instead of nonzero at the exit-status assertion; confirms the test reproduces the silent-drop defect before production changes.
- Remediation RED: the added `--cli --ref --bogus` case exited `0`, proving `--ref` could swallow an unknown option before the guard was added.
- GREEN: `pnpm --filter @mosaicstack/mosaic exec vitest run src/commands/install-arguments.spec.ts src/commands/install-heading.spec.ts` — 2 files, 3 tests passed.
- Situational process check: unknown positional input exited 2, named the input on STDERR, printed usage, and did not call the npm shim.
- `bash -n tools/install.sh` — passed.
- Bare `--ref` process check — exited 2 with `Missing value for --ref` and usage.
- `pnpm --filter @mosaicstack/mosaic test` — 69 files, 1,287 tests passed; framework shell checks passed. The first attempt lacked generated `dist/cli.js`; `pnpm --filter @mosaicstack/mosaic build` restored the required test precondition and the full rerun passed.
- `pnpm lint` — 23/23 tasks passed.
- `pnpm typecheck` — 42/42 tasks passed.
- `pnpm format:check` — passed.
- Codex code re-review against `origin/main` — `approve`, 0 blockers/should-fix/suggestions.
- Codex security re-review against `origin/main` — risk `none`, 0 findings.

## Acceptance evidence

| Criterion | Evidence |
| --- | --- |
| Unknown input is named on STDERR | Process-level Vitest assertions for `--bogus`, including after `--ref` |
| Short usage hint is printed on STDERR | Vitest usage regex + manual process output |
| Exit is nonzero | Vitest status assertions and manual exit 2 |
| Installation does not proceed | Isolated npm shim marker remains absent |
| Recognized behavior is preserved | Parser cases are unchanged except validation of malformed `--ref`; full Mosaic package suite passed |
| Part 2 is excluded | No `--next`, `MOSAIC_NEXT`, dist-tag, or prerelease routing changes |

## Documentation checklist

- Current canonical `docs/PRD.md` remains unchanged; issue #804 and the coordinator brief supply this bounded defect's acceptance contract.
- Updated installer behavior in root README, user guide, and packaged framework README in the same logical change set.
- API/OpenAPI, auth/permissions, admin operations, developer architecture, sitemap/navigation, and external publishing are not affected.
- Scratchpad remains under `docs/scratchpads/`; no root-hygiene changes.

## Risks and blockers

- Part 2 remains owner-gated under #805 and is intentionally excluded.
- No implementation blocker remains. Independent coordinator RoR, CI, merge, and issue closure remain pending after worker handoff.
