diff --git a/tests/bug-2519-sdk-tarball-dist.test.cjs b/tests/bug-2519-sdk-tarball-dist.test.cjs
new file mode 100644
index 00000000..e4dbce7e
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+++ b/tests/bug-2519-sdk-tarball-dist.test.cjs
@@ -0,0 +1,77 @@
+/**
+ * Regression test for #2519: @gsd-build/sdk tarball shipped without dist/
+ *
+ * The published 0.1.0 tarball lacked a `files` whitelist including `dist/` and
+ * a `prepublishOnly` hook to build `dist/` before publish. As a result the
+ * tarball contained only source and the declared `bin` target `./dist/cli.js`
+ * was absent at install time, breaking every `gsd-sdk query …` call.
+ *
+ * This test guards sdk/package.json so future edits cannot silently drop
+ * either safeguard.
+ */
+
+'use strict';
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+
+const SDK_PACKAGE_JSON = path.join(__dirname, '..', 'sdk', 'package.json');
+
+describe('bug #2519: sdk/package.json ships dist/ in tarball', () => {
+  const pkg = JSON.parse(fs.readFileSync(SDK_PACKAGE_JSON, 'utf-8'));
+
+  test('has a files whitelist (array) so publish is explicit', () => {
+    assert.ok(
+      Array.isArray(pkg.files),
+      'sdk/package.json must declare a `files` array so the tarball contents are explicit',
+    );
+    assert.ok(
+      pkg.files.length > 0,
+      '`files` array must not be empty',
+    );
+  });
+
+  test('files whitelist includes dist/ so compiled output is published', () => {
+    assert.ok(Array.isArray(pkg.files), '`files` must be an array');
+    const includesDist = pkg.files.some((entry) => {
+      if (typeof entry !== 'string') return false;
+      const normalized = entry.replace(/\\/g, '/').replace(/^\.\//, '');
+      return /^dist(?:$|\/|\/\*\*|\/\*\*\/\*)/.test(normalized);
+    });
+    assert.ok(
+      includesDist,
+      `sdk/package.json \`files\` must include "dist" so the published tarball contains the compiled CLI (bin target ./dist/cli.js). Found: ${JSON.stringify(pkg.files)}`,
+    );
+  });
+
+  test('has prepublishOnly script that runs a build', () => {
+    assert.ok(
+      pkg.scripts && typeof pkg.scripts === 'object',
+      'sdk/package.json must have a `scripts` object',
+    );
+    const prepub = pkg.scripts.prepublishOnly;
+    assert.ok(
+      typeof prepub === 'string' && prepub.length > 0,
+      'sdk/package.json must define `scripts.prepublishOnly` so dist/ is (re)built before every publish',
+    );
+    // Must invoke a build — either `npm run build`, `tsc`, or similar.
+    const looksLikeBuild = /\b(build|tsc)\b/.test(prepub);
+    assert.ok(
+      looksLikeBuild,
+      `scripts.prepublishOnly must run a build command (e.g. "npm run build" or "tsc"). Got: ${JSON.stringify(prepub)}`,
+    );
+  });
+
+  test('bin target lives under dist/ (sanity: the thing files+prepublish must ship)', () => {
+    assert.ok(pkg.bin, 'sdk/package.json must declare a `bin` field');
+    const binValues = typeof pkg.bin === 'string'
+      ? [pkg.bin]
+      : Object.values(pkg.bin);
+    assert.ok(
+      binValues.some((p) => typeof p === 'string' && p.includes('dist/')),
+      `bin target must reference dist/ — otherwise the files+prepublishOnly guard is pointless. Got: ${JSON.stringify(pkg.bin)}`,
+    );
+  });
+});