fix: reject unknown installer arguments (#825)

README.md

@@ -349,6 +349,8 @@ bash tools/install.sh --yes             # Non-interactive, accept all defaults
 bash tools/install.sh --no-auto-launch  # Skip auto-launch of wizard
 ```
 
+The installer rejects unrecognized flags or positional arguments before making changes and prints the supported-option usage.
+
 ## Contributing
 
 ```bash

docs/guides/user-guide.md

@@ -183,6 +183,8 @@ non-interactive use:
 --no-auto-launch    # Skip auto-launch of wizard after install
 ```
 
+Unrecognized flags or positional arguments fail before installation starts and print the supported-option usage.
+
 Or if installed globally:
 
 ```bash

docs/scratchpads/804-install-unknown-flags.md

@@ -0,0 +1,86 @@
+# 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.

packages/mosaic/framework/defaults/README.md

@@ -177,6 +177,8 @@ bash tools/install.sh --cli         # npm CLI only (skip framework)
 bash tools/install.sh --ref v1.0    # Install from a specific git ref
 ```
 
+The installer rejects unrecognized flags or positional arguments before making changes and prints the supported-option usage.
+
 ## Universal Skills
 
 The installer syncs skills from `mosaic/agent-skills` into `~/.config/mosaic/skills/`, then links each skill into runtime directories.

packages/mosaic/src/commands/install-arguments.spec.ts

@@ -0,0 +1,61 @@
+import { spawnSync } from 'node:child_process';
+import { existsSync } from 'node:fs';
+import { chmod, mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+const INSTALLER_PATH = fileURLToPath(new URL('../../../../tools/install.sh', import.meta.url));
+
+async function runInstaller(args: string[]): Promise<{
+  status: number | null;
+  stderr: string;
+  npmCalled: boolean;
+}> {
+  const home = await mkdtemp(join(tmpdir(), 'mosaic-installer-args-'));
+  const bin = join(home, 'bin');
+  const npmMarker = join(home, 'npm-called');
+
+  try {
+    await mkdir(bin);
+    const npmShim = join(bin, 'npm');
+    await writeFile(npmShim, `#!/bin/sh\n: > "${npmMarker}"\n`);
+    await chmod(npmShim, 0o755);
+
+    const result = spawnSync('bash', [INSTALLER_PATH, ...args], {
+      encoding: 'utf8',
+      env: {
+        ...process.env,
+        HOME: home,
+        MOSAIC_NO_COLOR: '1',
+        PATH: `${bin}:${process.env.PATH ?? ''}`,
+      },
+    });
+
+    return {
+      status: result.status,
+      stderr: result.stderr,
+      npmCalled: existsSync(npmMarker),
+    };
+  } finally {
+    await rm(home, { recursive: true, force: true });
+  }
+}
+
+function expectUnknownArgument(result: Awaited<ReturnType<typeof runInstaller>>): void {
+  expect(result.status).not.toBe(0);
+  expect(result.stderr).toContain('Unknown argument: --bogus');
+  expect(result.stderr).toMatch(/Usage: .*install\.sh/);
+  expect(result.npmCalled).toBe(false);
+}
+
+describe('installer arguments', () => {
+  it('rejects an unknown argument before installation starts', async () => {
+    expectUnknownArgument(await runInstaller(['--cli', '--bogus']));
+  });
+
+  it('does not let --ref consume an unknown option', async () => {
+    expectUnknownArgument(await runInstaller(['--cli', '--ref', '--bogus']));
+  });
+});

tools/install.sh

@@ -61,17 +61,38 @@ if [[ "${MOSAIC_DEV:-0}" == "1" ]]; then
   FLAG_DEV=true
 fi
 
+installer_usage() {
+  printf 'Usage: install.sh [--check] [--framework] [--cli] [--ref <branch>] [--dev] [--yes|-y] [--no-auto-launch] [--uninstall]\n' >&2
+}
+
 while [[ $# -gt 0 ]]; do
   case "$1" in
     --check)          FLAG_CHECK=true; shift ;;
     --framework)      FLAG_CLI=false; shift ;;
     --cli)            FLAG_FRAMEWORK=false; shift ;;
-    --ref)            GIT_REF="${2:-main}"; shift 2 ;;
+    --ref)
+      if [[ $# -lt 2 ]] || [[ -z "$2" ]]; then
+        printf 'Error: Missing value for --ref\n' >&2
+        installer_usage
+        exit 2
+      fi
+      if [[ "$2" == -* ]]; then
+        printf 'Error: Unknown argument: %s\n' "$2" >&2
+        installer_usage
+        exit 2
+      fi
+      GIT_REF="$2"
+      shift 2
+      ;;
     --dev)            FLAG_DEV=true; shift ;;
     --yes|-y)         FLAG_YES=true; shift ;;
     --no-auto-launch) FLAG_NO_AUTO_LAUNCH=true; shift ;;
     --uninstall)      FLAG_UNINSTALL=true; shift ;;
-    *)                shift ;;
+    *)
+      printf 'Error: Unknown argument: %s\n' "$1" >&2
+      installer_usage
+      exit 2
+      ;;
   esac
 done