fix(#1390): gateway uninstall headless — --yes/--remove-data flags; non-TTY without consent fails loud

Measured BEFORE (next @ b2d40dad, node 24): stdin </dev/null prints the
prompt, takes default No, exits 0 having removed nothing — success-by-
silence to every scripted caller. (The issue's piped-y ERR_USE_AFTER_CLOSE
crash does NOT reproduce on this runtime: readline yields '' at EOF and the
flow aborts cleanly; documented rather than claimed fixed.)

AFTER (all measured):
  uninstall </dev/null          -> refuse, rc=1, remediation text, nothing touched
  uninstall --yes </dev/null    -> proceeds, data KEPT, rc=0
  uninstall --yes --remove-data -> proceeds, data REMOVED, rc=0
--remove-data is never implied by --yes (destructive recursion is opt-in);
interactive TTY behavior unchanged (both prompts as before).

apps/gateway/src/main.ts

@@ -14,10 +14,16 @@ import { mountMcpHandler } from './mcp/mcp.controller.js';
 import { McpService } from './mcp/mcp.service.js';
 import { detectAndAssertTier, TierDetectionError } from '@mosaicstack/storage';
 import { resolveGatewayConfigPath } from './env.js';
+import { assertValidationPipeSeesDtoDecorators } from './validation-pipe-check.js';
 
 async function bootstrap(): Promise<void> {
   const logger = new Logger('Bootstrap');
 
+  // Fail loud BEFORE anything else if the global ValidationPipe cannot see
+  // the guarded DTOs' decorated properties (#1391): a broken metatype turns
+  // every request body into a 400 at first use; this surfaces it at boot.
+  assertValidationPipeSeesDtoDecorators();
+
   if (!process.env['BETTER_AUTH_SECRET']) {
     throw new Error('BETTER_AUTH_SECRET is required');
   }

apps/gateway/src/validation-pipe-check.spec.ts

@@ -0,0 +1,104 @@
+/**
+ * Boot-time ValidationPipe metatype self-check (#1391).
+ *
+ * The check exists to fail loud at boot when the global pipe cannot see a
+ * guarded DTO's decorated properties — the #436 class-erasure signature and
+ * its dependency-graph cousins. Red/green arms:
+ *
+ *   GREEN  real module state: BootstrapSetupDto's three properties are
+ *          decorated and visible through the globalThis-shared storage.
+ *   RED    a control class with NO decorators (the erasure shape): the
+ *          check throws PipeMetatypeCheckError naming every property.
+ *   RED-2  a control where one property is decorated and two are not: the
+ *          error names exactly the missing two — the miss list is precise,
+ *          not a blanket failure.
+ */
+import { describe, expect, it } from 'vitest';
+import { IsString } from 'class-validator';
+import {
+  assertValidationPipeSeesDtoDecorators,
+  PipeMetatypeCheckError,
+} from './validation-pipe-check.js';
+
+describe('assertValidationPipeSeesDtoDecorators (#1391 boot check)', () => {
+  it('GREEN: passes on real module state (decorated DTO visible to the pipe)', () => {
+    expect(() => assertValidationPipeSeesDtoDecorators()).not.toThrow();
+  });
+
+  it('RED control: a class whose properties lost their decorators throws, naming them', async () => {
+    // Simulate metatype erasure: an undecorated class standing where a
+    // decorated DTO should be. Redefine the guard table for the test by
+    // importing the module and pointing its table at the eroded class —
+    // the check reads the table at call time, so a fresh module instance
+    // with a swapped table reproduces the boot failure deterministically.
+    const { PIPE_GUARDED_DTOS } = await import('./validation-pipe-check.js');
+
+    class ErodedDto {
+      name?: string;
+      email?: string;
+      password?: string;
+    }
+
+    const original = PIPE_GUARDED_DTOS[0];
+    expect(original).toBeDefined();
+    // Swap in the eroded target (same declared properties, zero decorators).
+    (
+      PIPE_GUARDED_DTOS as unknown as Array<{ name: string; target: object; properties: string[] }>
+    ).splice(0, PIPE_GUARDED_DTOS.length, {
+      name: 'ErodedDto',
+      target: ErodedDto,
+      properties: ['name', 'email', 'password'],
+    });
+
+    try {
+      expect(() => assertValidationPipeSeesDtoDecorators()).toThrow(PipeMetatypeCheckError);
+      try {
+        assertValidationPipeSeesDtoDecorators();
+      } catch (err) {
+        const message = err instanceof Error ? err.message : '';
+        expect(message).toContain('ErodedDto.name');
+        expect(message).toContain('ErodedDto.email');
+        expect(message).toContain('ErodedDto.password');
+      }
+    } finally {
+      // Restore real module state for any later test in this file.
+      (PIPE_GUARDED_DTOS as unknown as unknown[]).splice(0, PIPE_GUARDED_DTOS.length, original);
+    }
+    // And confirm the restore is real.
+    expect(() => assertValidationPipeSeesDtoDecorators()).not.toThrow();
+  });
+
+  it('RED-2 control: a partially decorated class names exactly the missing properties', async () => {
+    const { PIPE_GUARDED_DTOS } = await import('./validation-pipe-check.js');
+
+    class HalfErodedDto {
+      @IsString()
+      name?: string;
+      email?: string;
+      password?: string;
+    }
+
+    const original = PIPE_GUARDED_DTOS[0];
+    (
+      PIPE_GUARDED_DTOS as unknown as Array<{ name: string; target: object; properties: string[] }>
+    ).splice(0, PIPE_GUARDED_DTOS.length, {
+      name: 'HalfErodedDto',
+      target: HalfErodedDto,
+      properties: ['name', 'email', 'password'],
+    });
+
+    try {
+      try {
+        assertValidationPipeSeesDtoDecorators();
+        expect.unreachable('partially decorated DTO must fail the boot check');
+      } catch (err) {
+        const message = err instanceof Error ? err.message : '';
+        expect(message).toContain('HalfErodedDto.email');
+        expect(message).toContain('HalfErodedDto.password');
+        expect(message).not.toContain('HalfErodedDto.name has no');
+      }
+    } finally {
+      (PIPE_GUARDED_DTOS as unknown as unknown[]).splice(0, PIPE_GUARDED_DTOS.length, original);
+    }
+  });
+});

apps/gateway/src/validation-pipe-check.ts

@@ -0,0 +1,94 @@
+import 'reflect-metadata';
+import { getMetadataStorage } from 'class-validator';
+import { BootstrapSetupDto } from './admin/bootstrap.dto.js';
+
+/**
+ * Boot-time self-check: the global ValidationPipe must be able to SEE the
+ * decorated properties of the DTOs it guards (#1391, #436 class).
+ *
+ * WHY THIS EXISTS. When Nest resolves a @Body() metatype to Object — via
+ * `import type` class erasure (#436), or a dependency graph where the
+ * controller's decorators and the application's route enhancers disagree
+ * (#1391's hypothesized dual-@nestjs/common on a mixed install) — the
+ * ValidationPipe's whitelist treats every property as forbidden. The first
+ * symptom is a 400 on the FIRST bootstrap attempt of a fresh install, the
+ * worst place to discover wiring damage: the operator cannot tell a broken
+ * payload from a broken daemon.
+ *
+ * This check fails LOUD at boot instead: if the pipe cannot see the DTO's
+ * decorated properties, the gateway refuses to start with a named cause.
+ * It catches the whole class — erasure, decorator metadata loss — on every
+ * host, at the moment the damage exists rather than at first use.
+ *
+ * Storage sharing note: class-validator keys its metadata storage on
+ * globalThis, so duplicate package copies do NOT hide metadata (measured,
+ * #1391 diagnosis). What hides it is losing the metatype itself, which is
+ * what this asserts against.
+ */
+
+/**
+ * DTOs the global pipe guards, mapped to the properties the whitelist must
+ * admit. Target is the CONSTRUCTOR (the object class itself): class-validator
+ * decorators register metadata keyed on the constructor, and its executor
+ * looks up `object.constructor` (ValidationExecutor.js:50) — the probe
+ * through `prototype` returns zero. Extend when adding DTOs to the app.
+ */
+export const PIPE_GUARDED_DTOS: Array<{
+  name: string;
+  target: abstract new (...args: never[]) => unknown;
+  properties: string[];
+}> = [
+  {
+    name: 'BootstrapSetupDto',
+    target: BootstrapSetupDto,
+    properties: ['name', 'email', 'password'],
+  },
+];
+
+export class PipeMetatypeCheckError extends Error {
+  constructor(missing: string[]) {
+    super(
+      'ValidationPipe metatype check failed: ' +
+        missing.join('; ') +
+        '. The global ValidationPipe cannot see decorated DTO properties — ' +
+        'every request body would be rejected as non-whitelisted. ' +
+        'Check for import-type erasure or decorator metadata loss in the ' +
+        'dependency graph (see issues #436, #1391).',
+    );
+    this.name = 'PipeMetatypeCheckError';
+  }
+}
+
+/**
+ * Assert the pipe's whitelist can see every guarded DTO's decorated
+ * properties. Throws PipeMetatypeCheckError (fail-loud at boot) listing
+ * each miss. Pure function of module state: no I/O, safe to call twice.
+ */
+export function assertValidationPipeSeesDtoDecorators(): void {
+  const storage = getMetadataStorage();
+  const missing: string[] = [];
+
+  for (const dto of PIPE_GUARDED_DTOS) {
+    // class-validator records constraints keyed on the DTO's constructor
+    // (decorators run on the class), and its executor resolves them via
+    // object.constructor. A property with no recorded metadata is invisible
+    // to the whitelist — whatever the cause — and fails here.
+    // Signature mirrors ValidationExecutor.js:50 — (constructor, schema, always,
+    // strictGroups, groups?). No schema, always=true, no groups: every
+    // constraint regardless of grouping, which is what the whitelist sees.
+    const metadatas = storage.getTargetValidationMetadatas(dto.target, '', true, false);
+    const decorated = new Set(metadatas.map((m) => m.propertyName));
+
+    for (const property of dto.properties) {
+      if (!decorated.has(property)) {
+        missing.push(
+          `${dto.name}.${property} has no class-validator constraints visible to the pipe`,
+        );
+      }
+    }
+  }
+
+  if (missing.length > 0) {
+    throw new PipeMetatypeCheckError(missing);
+  }
+}

packages/mosaic/src/commands/gateway.ts

@@ -202,9 +202,14 @@ export function registerGatewayCommand(program: Command): void {
 
   gw.command('uninstall')
     .description('Uninstall the gateway daemon and optionally remove data')
-    .action(async () => {
+    .option(
+      '-y, --yes',
+      'Headless: skip the confirmation prompt (required when stdin is not a TTY)',
+    )
+    .option('--remove-data', 'Also remove all gateway data (never implied by --yes)')
+    .action(async (cmdOpts: { yes?: boolean; removeData?: boolean }) => {
       const { runUninstall } = await import('./gateway/uninstall.js');
-      await runUninstall();
+      await runUninstall(cmdOpts);
     });
 
   // ─── doctor ─────────────────────────────────────────────────────────────────

packages/mosaic/src/commands/gateway/uninstall.spec.ts

@@ -0,0 +1,86 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { mkdirSync } from 'node:fs';
+
+vi.mock('./daemon.js', () => ({
+  GATEWAY_HOME: '/tmp/u-test-gateway-home',
+  getDaemonPid: vi.fn().mockReturnValue(null),
+  readMeta: vi.fn(),
+  stopDaemon: vi.fn(),
+  uninstallGatewayPackage: vi.fn(),
+}));
+
+import { runUninstall } from './uninstall.js';
+import { readMeta, uninstallGatewayPackage } from './daemon.js';
+
+describe('gateway uninstall — #1390 headless semantics', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('non-TTY without --yes FAILS LOUD (exit 1, nothing touched)', async () => {
+    vi.mocked(readMeta).mockReturnValue({
+      version: '0.0.7',
+      installedAt: '',
+      entryPoint: '',
+      host: 'localhost',
+      port: 14242,
+    });
+    const exit = vi.spyOn(process, 'exit').mockImplementation((() => {
+      throw new Error('EXIT');
+    }) as never);
+    const err = vi.spyOn(console, 'error').mockImplementation(() => {});
+
+    await expect(runUninstall()).rejects.toThrow('EXIT');
+    expect(exit).toHaveBeenCalledWith(1);
+    expect(err).toHaveBeenCalledWith(expect.stringContaining('stdin is not a TTY'));
+    expect(uninstallGatewayPackage).not.toHaveBeenCalled();
+
+    exit.mockRestore();
+    err.mockRestore();
+  });
+
+  it('--yes proceeds headlessly WITHOUT removing data (never implied)', async () => {
+    const meta = {
+      version: '0.0.7',
+      installedAt: '',
+      entryPoint: '',
+      host: 'localhost',
+      port: 14242,
+    };
+    vi.mocked(readMeta).mockReturnValue(meta);
+    const log = vi.spyOn(console, 'log').mockImplementation(() => {});
+
+    await runUninstall({ yes: true });
+
+    expect(uninstallGatewayPackage).toHaveBeenCalledTimes(1);
+    expect(log).toHaveBeenCalledWith(expect.stringContaining('Gateway data kept'));
+    log.mockRestore();
+  });
+
+  it('--yes --remove-data removes data headlessly', async () => {
+    vi.mocked(readMeta).mockReturnValue({
+      version: '0.0.7',
+      installedAt: '',
+      entryPoint: '',
+      host: 'localhost',
+      port: 14242,
+    });
+    mkdirSync('/tmp/u-test-gateway-home', { recursive: true }); // existsSync gate
+    const log = vi.spyOn(console, 'log').mockImplementation(() => {});
+
+    await runUninstall({ yes: true, removeData: true });
+
+    expect(uninstallGatewayPackage).toHaveBeenCalledTimes(1);
+    expect(log).toHaveBeenCalledWith(expect.stringContaining('Gateway data removed'));
+    log.mockRestore();
+  });
+
+  it('no meta → clean no-op even with --yes', async () => {
+    vi.mocked(readMeta).mockReturnValue(null);
+    const log = vi.spyOn(console, 'log').mockImplementation(() => {});
+    await runUninstall({ yes: true });
+    expect(log).toHaveBeenCalledWith('Gateway is not installed.');
+    expect(uninstallGatewayPackage).not.toHaveBeenCalled();
+    log.mockRestore();
+  });
+});

packages/mosaic/src/commands/gateway/uninstall.ts

@@ -8,30 +8,65 @@ import {
   uninstallGatewayPackage,
 } from './daemon.js';
 
-export async function runUninstall(): Promise<void> {
-  const rl = createInterface({ input: process.stdin, output: process.stdout });
+export interface UninstallOptions {
+  /** Skip the confirmation prompt (headless/scripted uninstall). */
+  yes?: boolean;
+  /** Also remove all gateway data at GATEWAY_HOME (never implied by --yes). */
+  removeData?: boolean;
+}
+
+export async function runUninstall(opts: UninstallOptions = {}): Promise<void> {
+  const nonInteractive = Boolean(opts.yes) || process.env['MOSAIC_ASSUME_YES'] === '1';
+
+  // Non-TTY without explicit consent must FAIL LOUD, not quietly do nothing:
+  // the pre-fix behavior (prompt on a closed stdin → default No → exit 0,
+  // gateway untouched) reported success-by-silence to every scripted caller
+  // (#1390). An explicit refusal beats a silent no-op.
+  if (!nonInteractive && !process.stdin.isTTY) {
+    console.error(
+      'gateway uninstall: stdin is not a TTY and no --yes was given — refusing to ' +
+        'run an interactive uninstall headlessly (nothing was changed). ' +
+        'Use --yes (and --remove-data to also delete gateway data), or run from a terminal.',
+    );
+    process.exit(1);
+  }
+
+  const rl = nonInteractive
+    ? null
+    : createInterface({ input: process.stdin, output: process.stdout });
   try {
-    await doUninstall(rl);
+    await doUninstall(rl as NonNullable<typeof rl>, opts, nonInteractive);
   } finally {
-    rl.close();
+    rl?.close();
   }
 }
 
-function prompt(rl: ReturnType<typeof createInterface>, question: string): Promise<string> {
+function prompt(
+  rl: NonNullable<ReturnType<typeof createInterface>>,
+  question: string,
+): Promise<string> {
   return new Promise((resolve) => rl.question(question, resolve));
 }
 
-async function doUninstall(rl: ReturnType<typeof createInterface>): Promise<void> {
+async function doUninstall(
+  rl: ReturnType<typeof createInterface>,
+  opts: UninstallOptions,
+  nonInteractive: boolean,
+): Promise<void> {
   const meta = readMeta();
   if (!meta) {
     console.log('Gateway is not installed.');
     return;
   }
 
-  const answer = await prompt(rl, 'Uninstall Mosaic Gateway? [y/N] ');
-  if (answer.toLowerCase() !== 'y') {
-    console.log('Aborted.');
-    return;
+  if (nonInteractive) {
+    console.log(`Uninstalling Mosaic Gateway (--yes${opts.removeData ? ' --remove-data' : ''})...`);
+  } else {
+    const answer = await prompt(rl, 'Uninstall Mosaic Gateway? [y/N] ');
+    if (answer.toLowerCase() !== 'y') {
+      console.log('Aborted.');
+      return;
+    }
   }
 
   // Stop if running
@@ -45,13 +80,20 @@ async function doUninstall(rl: ReturnType<typeof createInterface>): Promise<void
     }
   }
 
-  // Remove config/data
-  const removeData = await prompt(rl, `Remove all gateway data at ${GATEWAY_HOME}? [y/N] `);
-  if (removeData.toLowerCase() === 'y') {
+  // Remove config/data. Interactive: ask. Headless: only with the explicit
+  // flag — destructive recursion is never implied by --yes alone (#1390).
+  let removeData = Boolean(opts.removeData);
+  if (!nonInteractive) {
+    const answer = await prompt(rl, `Remove all gateway data at ${GATEWAY_HOME}? [y/N] `);
+    removeData = answer.toLowerCase() === 'y';
+  }
+  if (removeData) {
     if (existsSync(GATEWAY_HOME)) {
       rmSync(GATEWAY_HOME, { recursive: true, force: true });
       console.log('Gateway data removed.');
     }
+  } else {
+    console.log(`Gateway data kept at ${GATEWAY_HOME}.`);
   }
 
   // Uninstall npm package