diff --git a/bin/flavian.mjs b/bin/flavian.mjs
index ec3bf6f..ba3cbbb 100755
--- a/bin/flavian.mjs
+++ b/bin/flavian.mjs
@@ -77,7 +77,7 @@ async function runIndesign(args) {
 			case '--quiet': case '-q': opts.quiet = true; break;
 			case '-h': case '--help': printIndesignUsage(); process.exit(0); break;
 			default:
-				if (!input && !arg.startsWith('-')) input = arg;
+				if (!input && (arg === '-' || !arg.startsWith('-'))) input = arg;
 				else { fail(`Unknown argument: ${arg}`); printIndesignUsage(); process.exit(2); }
 		}
 	}
diff --git a/packages/pipeline/bin/generate-theme.mjs b/packages/pipeline/bin/generate-theme.mjs
index a51d8ed..1fdca0d 100644
--- a/packages/pipeline/bin/generate-theme.mjs
+++ b/packages/pipeline/bin/generate-theme.mjs
@@ -65,7 +65,7 @@ for (; i < args.length; i += 1) {
 		case '--quiet': opts.quiet = true; break;
 		case '-h': case '--help': printUsage(); process.exit(0); break;
 		default:
-			if (!inputPath && !arg.startsWith('-')) {
+    		if (!inputPath && (arg === '-' || !arg.startsWith('-'))) {
 				inputPath = arg;
 			} else {
 				process.stderr.write(`Unknown argument: ${arg}\n`);
diff --git a/packages/pipeline/bin/map-tokens.mjs b/packages/pipeline/bin/map-tokens.mjs
index a3b1779..da9b8f2 100644
--- a/packages/pipeline/bin/map-tokens.mjs
+++ b/packages/pipeline/bin/map-tokens.mjs
@@ -57,7 +57,7 @@ for (; i < args.length; i += 1) {
 		case '--quiet': opts.quiet = true; break;
 		case '-h': case '--help': printUsage(); process.exit(0); break;
 		default:
-			if (!inputPath && !arg.startsWith('-')) {
+		    if (!inputPath && (arg === '-' || !arg.startsWith('-'))) {
 				inputPath = arg;
 			} else {
 				process.stderr.write(`Unknown argument: ${arg}\n`);
diff --git a/packages/pipeline/tests/indesign/stdin-sentinel.test.mjs b/packages/pipeline/tests/indesign/stdin-sentinel.test.mjs
new file mode 100644
index 0000000..d945042
--- /dev/null
+++ b/packages/pipeline/tests/indesign/stdin-sentinel.test.mjs
@@ -0,0 +1,181 @@
+// Regression tests for issue #148 — bare "-" accepted as stdin sentinel.
+//
+// Each affected CLI entry point is invoked as a child process with "-" as the
+// positional argument and a minimal IR JSON piped on stdin. The process must
+// NOT exit 2 (unknown-argument error) and must not print "Unknown argument: -".
+//
+// Reference: the fix mirrors packages/pipeline/bin/ingest.mjs:53 which already
+// handles "-" correctly and serves as the canonical pattern.
+
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { spawn } from 'node:child_process';
+import { mkdtemp, rm } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { ingestBuffer, toArtifact } from '../../src/indesign/ingest/index.js';
+import { buildIdml } from './helpers/build-idml.js';
+
+const ROOT = path.resolve(fileURLToPath(new URL('../../../../', import.meta.url)));
+
+// Build a minimal but valid IR JSON to pipe into each bin.
+async function makeIrJson() {
+	const bytes = buildIdml({
+		name: 'Stdin Sentinel Test',
+		colors: [],
+		fonts: [{ id: 'f', family: 'Helvetica', style: 'Regular', postScriptName: 'Helvetica' }],
+		styles: [{ id: 'h1', name: 'Heading 1', kind: 'paragraph', pointSize: 24, appliedFont: 'f' }],
+		stories: [{ id: 's1', runs: [{ text: 'Hello', paragraphStyle: 'h1' }] }],
+		spreads: [{
+			id: 'sp1',
+			pages: [{ id: 'p1', bounds: [0, 0, 792, 612] }],
+			frames: [{ kind: 'text', id: 'tf1', bounds: [60, 60, 150, 540], parentStory: 's1' }],
+		}],
+	});
+	const result = await ingestBuffer(bytes);
+	return JSON.stringify(toArtifact(result));
+}
+
+// Spawn a bin with args, write stdin, collect exit code + output.
+function run(binRelPath, args, stdinData) {
+	return new Promise((resolve) => {
+		const bin = path.join(ROOT, binRelPath);
+		const child = spawn(process.execPath, [bin, ...args], {
+			stdio: ['pipe', 'pipe', 'pipe'],
+			cwd: ROOT,
+		});
+		if (stdinData) {
+			child.stdin.write(stdinData);
+		}
+		child.stdin.end();
+		const out = [];
+		const err = [];
+		child.stdout.on('data', (d) => out.push(d));
+		child.stderr.on('data', (d) => err.push(d));
+		child.on('close', (code) => resolve({
+			code,
+			stdout: Buffer.concat(out).toString(),
+			stderr: Buffer.concat(err).toString(),
+		}));
+	});
+}
+
+// ── generate-theme ────────────────────────────────────────────────────────────
+
+test('generate-theme: "-" is accepted as the stdin sentinel', async () => {
+	const ir = await makeIrJson();
+	const outDir = await mkdtemp(path.join(tmpdir(), 'flavian-gt-stdin-'));
+	try {
+		const { code, stderr } = await run(
+			'packages/pipeline/bin/generate-theme.mjs',
+			['-', '--out-dir', outDir, '--quiet'],
+			ir,
+		);
+		assert.ok(
+			!stderr.includes('Unknown argument: -'),
+			`should not reject "-" — stderr: ${stderr}`,
+		);
+		assert.notEqual(code, 2, `exited 2 (argument error) — stderr: ${stderr}`);
+	} finally {
+		await rm(outDir, { recursive: true, force: true });
+	}
+});
+
+test('generate-theme: omitting the positional still reads stdin (existing workaround)', async () => {
+	const ir = await makeIrJson();
+	const outDir = await mkdtemp(path.join(tmpdir(), 'flavian-gt-nostdin-'));
+	try {
+		const { code, stderr } = await run(
+			'packages/pipeline/bin/generate-theme.mjs',
+			['--out-dir', outDir, '--quiet'],
+			ir,
+		);
+		assert.notEqual(code, 2, `exited 2 — stderr: ${stderr}`);
+	} finally {
+		await rm(outDir, { recursive: true, force: true });
+	}
+});
+
+test('generate-theme: still rejects a genuinely unknown flag', async () => {
+	const { code, stderr } = await run(
+		'packages/pipeline/bin/generate-theme.mjs',
+		['--unknown-flag', '--out-dir', '/tmp/x', '--quiet'],
+		'',
+	);
+	assert.equal(code, 2, 'should exit 2 for an unknown flag');
+	assert.ok(stderr.includes('Unknown argument: --unknown-flag'));
+});
+
+// ── map-tokens ────────────────────────────────────────────────────────────────
+
+test('map-tokens: "-" is accepted as the stdin sentinel', async () => {
+	const ir = await makeIrJson();
+	const { code, stderr, stdout } = await run(
+		'packages/pipeline/bin/map-tokens.mjs',
+		['-', '--quiet'],
+		ir,
+	);
+	assert.ok(
+		!stderr.includes('Unknown argument: -'),
+		`should not reject "-" — stderr: ${stderr}`,
+	);
+	assert.notEqual(code, 2, `exited 2 (argument error) — stderr: ${stderr}`);
+	// stdout should be valid JSON (the theme.json partial)
+	assert.doesNotThrow(
+		() => JSON.parse(stdout),
+		'stdout should be a valid JSON theme partial',
+	);
+});
+
+test('map-tokens: omitting the positional still reads stdin (existing workaround)', async () => {
+	const ir = await makeIrJson();
+	const { code, stderr } = await run(
+		'packages/pipeline/bin/map-tokens.mjs',
+		['--quiet'],
+		ir,
+	);
+	assert.notEqual(code, 2, `exited 2 — stderr: ${stderr}`);
+});
+
+test('map-tokens: still rejects a genuinely unknown flag', async () => {
+	const { code, stderr } = await run(
+		'packages/pipeline/bin/map-tokens.mjs',
+		['--unknown-flag', '--quiet'],
+		'',
+	);
+	assert.equal(code, 2, 'should exit 2 for an unknown flag');
+	assert.ok(stderr.includes('Unknown argument: --unknown-flag'));
+});
+
+// ── flavian pipeline indesign ─────────────────────────────────────────────────
+
+test('flavian pipeline indesign: "-" is accepted as the stdin sentinel', async () => {
+	const ir = await makeIrJson();
+	const outDir = await mkdtemp(path.join(tmpdir(), 'flavian-id-stdin-'));
+	try {
+		const { code, stderr } = await run(
+			'bin/flavian.mjs',
+			['pipeline', 'indesign', '-', '--output', outDir, '--quiet'],
+			ir,
+		);
+		assert.ok(
+			!stderr.includes('Unknown argument: -'),
+			`should not reject "-" — stderr: ${stderr}`,
+		);
+		assert.notEqual(code, 2, `exited 2 (argument error) — stderr: ${stderr}`);
+	} finally {
+		await rm(outDir, { recursive: true, force: true });
+	}
+});
+
+test('flavian pipeline indesign: still rejects a genuinely unknown flag', async () => {
+	const { code, stderr } = await run(
+		'bin/flavian.mjs',
+		['pipeline', 'indesign', '--unknown-flag', '--quiet'],
+		'',
+	);
+	assert.equal(code, 2, 'should exit 2 for an unknown flag');
+	assert.ok(stderr.includes('Unknown argument: --unknown-flag'));
+});