diff --git a/.changeset/cli-honor-log-level.md b/.changeset/cli-honor-log-level.md
new file mode 100644
index 000000000..cfc796dfc
--- /dev/null
+++ b/.changeset/cli-honor-log-level.md
@@ -0,0 +1,9 @@
+---
+"@objectstack/cli": patch
+---
+
+fix(cli): honor OS_LOG_LEVEL / --log-level instead of hardcoding the kernel logger to `silent` (#1533)
+
+`os serve` / `os start` built the runtime kernel with a hardcoded `{ level: 'silent' }` logger, suppressing every plugin `logger.warn` / `logger.error`. A record-change flow whose condition or node faulted (surfaced via `logger.warn` in `plugin-trigger-record-change`) produced zero operator-visible output — the flow simply had no effect — undercutting ADR-0032's "fail loudly" promise when run via the CLI.
+
+The kernel logger level is now resolved from `--verbose` (→ `debug`) → `--log-level <level>` → `$OS_LOG_LEVEL` / `$LOG_LEVEL` → default `warn`. Defaulting to `warn` surfaces flow/hook execution-failure warnings and automation-engine errors out of the box, while the existing boot-quiet window still suppresses info-level startup chatter. Pass `--log-level silent` (or `OS_LOG_LEVEL=silent`) to restore the previous fully-quiet behavior. `start` and `dev` gain a matching `--log-level` flag and forward it (plus the existing `--verbose`) to the spawned `serve`.
diff --git a/packages/cli/src/commands/dev.ts b/packages/cli/src/commands/dev.ts
index f91ccc5a4..4b53672cf 100644
--- a/packages/cli/src/commands/dev.ts
+++ b/packages/cli/src/commands/dev.ts
@@ -20,7 +20,11 @@ export default class Dev extends Command {
   static override flags = {
     watch: Flags.boolean({ char: 'w', description: 'Enable watch mode (default)', default: true }),
     ui: Flags.boolean({ description: 'Enable the bundled Console portal at /_console/' }),
-    verbose: Flags.boolean({ char: 'v', description: 'Verbose output' }),
+    verbose: Flags.boolean({ char: 'v', description: 'Verbose output (shortcut for --log-level debug)' }),
+    'log-level': Flags.string({
+      description: 'Kernel logger level forwarded to `serve` (overrides $OS_LOG_LEVEL / $LOG_LEVEL; default `warn`). One of: debug | info | warn | error | fatal | silent.',
+      options: ['debug', 'info', 'warn', 'error', 'fatal', 'silent'],
+    }),
     port: Flags.string({ char: 'p', description: 'Server port (overrides $PORT)' }),
     preset: Flags.string({
       description: 'Plugin tier preset forwarded to `serve`: minimal | default | full',
@@ -212,6 +216,7 @@ export default class Dev extends Command {
           ...(port ? ['--port', port] : []),
           ...(flags.ui ? ['--ui'] : []),
           ...(flags.verbose ? ['--verbose'] : []),
+          ...(flags['log-level'] ? ['--log-level', flags['log-level']] : []),
           ...(flags.preset ? ['--preset', flags.preset] : []),
         ],
         // 'ipc' adds a message channel so the serve child can report the
diff --git a/packages/cli/src/commands/serve.ts b/packages/cli/src/commands/serve.ts
index 4410e9bed..3c1830edf 100644
--- a/packages/cli/src/commands/serve.ts
+++ b/packages/cli/src/commands/serve.ts
@@ -10,6 +10,7 @@ import { loadConfig, BUNDLE_REQUIRE_EXTERNALS } from '../utils/config.js';
 import { isHostConfig, shouldBootWithLibrary } from '../utils/plugin-detection.js';
 import { readEnvWithDeprecation } from '@objectstack/types';
 import { resolveObjectStackHome } from '@objectstack/runtime';
+import { LOG_LEVELS, resolveLogLevel, readLogLevelEnv } from '../utils/log-level.js';
 import {
   printHeader,
   printKV,
@@ -158,6 +159,11 @@ export default class Serve extends Command {
       description: 'Plugin tier preset: minimal | default | full (overridden by config.tiers if set)',
       options: ['minimal', 'default', 'full'],
     }),
+    'log-level': Flags.string({
+      description: 'Kernel logger level. Defaults to $OS_LOG_LEVEL / $LOG_LEVEL, else `warn` so flow/hook execution failures surface (ADR-0032). Use `silent` to fully quiet the runtime.',
+      options: [...LOG_LEVELS],
+    }),
+    verbose: Flags.boolean({ char: 'v', description: 'Verbose output — shortcut for --log-level debug.' }),
   };
 
   /**
@@ -481,8 +487,18 @@ export default class Serve extends Command {
       // Import ObjectStack runtime
       const { Runtime } = await import('@objectstack/runtime');
 
-      // Set kernel logger to 'silent' — the CLI manages its own output
-      const loggerConfig = { level: 'silent' as const };
+      // Resolve the kernel logger level. Honors --verbose / --log-level and
+      // $OS_LOG_LEVEL / $LOG_LEVEL, defaulting to `warn` so flow/hook
+      // execution failures surface even when the CLI manages its own output
+      // (ADR-0032 "fail loudly"; see #1533). `--log-level silent` restores the
+      // old fully-quiet behavior.
+      const loggerConfig = {
+        level: resolveLogLevel({
+          verbose: flags.verbose,
+          flag: flags['log-level'],
+          envLevel: readLogLevelEnv(),
+        }),
+      };
 
       const runtime = new Runtime({
         kernel: {
diff --git a/packages/cli/src/commands/start.ts b/packages/cli/src/commands/start.ts
index 4033d6b6f..805399fbf 100644
--- a/packages/cli/src/commands/start.ts
+++ b/packages/cli/src/commands/start.ts
@@ -62,7 +62,11 @@ export default class Start extends Command {
       default: true,
       allowNo: true,
     }),
-    verbose: Flags.boolean({ char: 'v', description: 'Verbose output' }),
+    verbose: Flags.boolean({ char: 'v', description: 'Verbose output (shortcut for --log-level debug)' }),
+    'log-level': Flags.string({
+      description: 'Kernel logger level forwarded to `serve` (overrides $OS_LOG_LEVEL / $LOG_LEVEL; default `warn`). One of: debug | info | warn | error | fatal | silent.',
+      options: ['debug', 'info', 'warn', 'error', 'fatal', 'silent'],
+    }),
 
     // Home directory — where persistent runtime state lives.
     home: Flags.string({
@@ -241,6 +245,7 @@ export default class Start extends Command {
         'serve',
         flags.ui ? '--ui' : '--no-ui',
         ...(flags.verbose ? ['--verbose'] : []),
+        ...(flags['log-level'] ? ['--log-level', flags['log-level']] : []),
       ],
       { stdio: 'inherit', env: localEnv },
     );
diff --git a/packages/cli/src/utils/log-level.ts b/packages/cli/src/utils/log-level.ts
new file mode 100644
index 000000000..fcb29547a
--- /dev/null
+++ b/packages/cli/src/utils/log-level.ts
@@ -0,0 +1,54 @@
+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+import { readEnvWithDeprecation } from '@objectstack/types';
+
+// ---------------------------------------------------------------------------
+// Kernel logger level resolution (shared by `serve`, and forwarded by
+// `start` / `dev`).
+//
+// `serve` used to hard-pin the kernel logger to `silent` so the CLI could own
+// a clean startup banner. That silenced every runtime fault plugins surface
+// through `logger.warn` / `logger.error` — most importantly the record-change
+// trigger's flow-execution-failure warnings and the automation engine's
+// internal errors — making a faulting flow fail completely silently and
+// defeating ADR-0032's "fail loudly" promise (see #1533).
+//
+// The level is resolved from (in precedence order):
+//   1. `--verbose`            → `debug`
+//   2. `--log-level <level>`  → explicit level
+//   3. `$OS_LOG_LEVEL` / `$LOG_LEVEL`
+//   4. default                → `warn`
+//
+// The default is `warn` rather than `silent`: warnings + errors reach the
+// operator out of the box while the boot-quiet window in `serve` still
+// suppresses the noisier info-level startup chatter. Pass `--log-level silent`
+// (or `OS_LOG_LEVEL=silent`) to restore the fully-quiet behavior.
+// ---------------------------------------------------------------------------
+export const LOG_LEVELS = ['debug', 'info', 'warn', 'error', 'fatal', 'silent'] as const;
+export type CliLogLevel = (typeof LOG_LEVELS)[number];
+
+/** Default kernel logger level when nothing is configured. */
+export const DEFAULT_LOG_LEVEL: CliLogLevel = 'warn';
+
+/**
+ * Resolve the kernel logger level from CLI flags and an explicit env value.
+ * Unknown / malformed levels fall back to {@link DEFAULT_LOG_LEVEL} rather
+ * than throwing, so a typo never crashes the server boot.
+ */
+export function resolveLogLevel(opts: {
+  verbose?: boolean;
+  flag?: string;
+  envLevel?: string;
+}): CliLogLevel {
+  if (opts.verbose) return 'debug';
+  const raw = (opts.flag ?? opts.envLevel ?? DEFAULT_LOG_LEVEL).toLowerCase().trim();
+  return (LOG_LEVELS as readonly string[]).includes(raw) ? (raw as CliLogLevel) : DEFAULT_LOG_LEVEL;
+}
+
+/**
+ * Read `$OS_LOG_LEVEL` (preferred) / `$LOG_LEVEL` (legacy) from the
+ * environment, emitting the standard deprecation warning for the legacy name.
+ */
+export function readLogLevelEnv(): string | undefined {
+  return readEnvWithDeprecation('OS_LOG_LEVEL', 'LOG_LEVEL');
+}
diff --git a/packages/cli/test/serve-log-level.test.ts b/packages/cli/test/serve-log-level.test.ts
new file mode 100644
index 000000000..280f84414
--- /dev/null
+++ b/packages/cli/test/serve-log-level.test.ts
@@ -0,0 +1,43 @@
+import { describe, expect, it } from 'vitest';
+import { resolveLogLevel, LOG_LEVELS, DEFAULT_LOG_LEVEL } from '../src/utils/log-level.js';
+
+describe('serve: resolveLogLevel', () => {
+  it('defaults to warn (not silent) — the #1533 regression guard', () => {
+    expect(DEFAULT_LOG_LEVEL).toBe('warn');
+  });
+
+  // Regression guard for #1533: the CLI must NOT silently default to
+  // 'silent', or runtime flow/hook execution failures (logged at warn+)
+  // are invisible, defeating ADR-0032's "fail loudly" promise.
+  it('defaults to `warn` when nothing is set', () => {
+    expect(resolveLogLevel({})).toBe('warn');
+  });
+
+  it('honors $OS_LOG_LEVEL / $LOG_LEVEL value', () => {
+    expect(resolveLogLevel({ envLevel: 'info' })).toBe('info');
+    expect(resolveLogLevel({ envLevel: 'silent' })).toBe('silent');
+  });
+
+  it('--log-level flag wins over the env value', () => {
+    expect(resolveLogLevel({ flag: 'error', envLevel: 'info' })).toBe('error');
+  });
+
+  it('--verbose wins over everything and maps to `debug`', () => {
+    expect(resolveLogLevel({ verbose: true, flag: 'error', envLevel: 'silent' })).toBe('debug');
+  });
+
+  it('is case-insensitive and trims surrounding whitespace', () => {
+    expect(resolveLogLevel({ flag: '  DEBUG ' })).toBe('debug');
+  });
+
+  it('falls back to `warn` for an unrecognized level rather than throwing', () => {
+    expect(resolveLogLevel({ envLevel: 'verbose' })).toBe('warn');
+    expect(resolveLogLevel({ flag: 'loud' })).toBe('warn');
+  });
+
+  it('accepts every documented level verbatim', () => {
+    for (const level of LOG_LEVELS) {
+      expect(resolveLogLevel({ flag: level })).toBe(level);
+    }
+  });
+});