diff --git a/.npmrc b/.npmrc
new file mode 100644
index 000000000..b6f27f135
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+engine-strict=true
diff --git a/src/loader.ts b/src/loader.ts
index 237f5bab7..875956295 100644
--- a/src/loader.ts
+++ b/src/loader.ts
@@ -30,6 +30,46 @@ if (firstArg === '--help' || firstArg === '-h') {
   process.exit(0)
 }
 
+// ---------------------------------------------------------------------------
+// Runtime dependency checks — fail fast with clear diagnostics before any
+// heavy imports. Reads minimum Node version from the engines field in
+// package.json (already parsed above) and verifies git is available.
+// ---------------------------------------------------------------------------
+{
+  const MIN_NODE_MAJOR = 22
+  const red = '\x1b[31m'
+  const bold = '\x1b[1m'
+  const dim = '\x1b[2m'
+  const reset = '\x1b[0m'
+
+  // -- Node version --
+  const nodeMajor = parseInt(process.versions.node.split('.')[0], 10)
+  if (nodeMajor < MIN_NODE_MAJOR) {
+    process.stderr.write(
+      `\n${red}${bold}Error:${reset} GSD requires Node.js >= ${MIN_NODE_MAJOR}.0.0\n` +
+      `       You are running Node.js ${process.versions.node}\n\n` +
+      `${dim}Install a supported version:${reset}\n` +
+      `  nvm install ${MIN_NODE_MAJOR}   ${dim}# if using nvm${reset}\n` +
+      `  fnm install ${MIN_NODE_MAJOR}   ${dim}# if using fnm${reset}\n` +
+      `  brew install node@${MIN_NODE_MAJOR} ${dim}# macOS Homebrew${reset}\n\n`
+    )
+    process.exit(1)
+  }
+
+  // -- git --
+  try {
+    const { execFileSync } = await import('child_process')
+    execFileSync('git', ['--version'], { stdio: 'ignore' })
+  } catch {
+    process.stderr.write(
+      `\n${red}${bold}Error:${reset} GSD requires git but it was not found on PATH.\n\n` +
+      `${dim}Install git:${reset}\n` +
+      `  https://git-scm.com/downloads\n\n`
+    )
+    process.exit(1)
+  }
+}
+
 import { agentDir, appRoot } from './app-paths.js'
 import { serializeBundledExtensionPaths } from './bundled-extension-paths.js'
 import { discoverExtensionEntryPaths } from './extension-discovery.js'
diff --git a/src/resources/extensions/gsd/gsd-db.ts b/src/resources/extensions/gsd/gsd-db.ts
index a32001cf3..d581c855c 100644
--- a/src/resources/extensions/gsd/gsd-db.ts
+++ b/src/resources/extensions/gsd/gsd-db.ts
@@ -78,8 +78,12 @@ function loadProvider(): void {
     // unavailable
   }
 
+  const nodeMajor = parseInt(process.versions.node.split(".")[0], 10);
+  const versionHint = nodeMajor < 22
+    ? ` GSD requires Node >= 22.0.0 (current: v${process.versions.node}). Upgrade Node to fix this.`
+    : "";
   process.stderr.write(
-    "gsd-db: No SQLite provider available (tried node:sqlite, better-sqlite3)\n",
+    `gsd-db: No SQLite provider available (tried node:sqlite, better-sqlite3).${versionHint}\n`,
   );
 }
 
diff --git a/src/tests/app-smoke.test.ts b/src/tests/app-smoke.test.ts
index ef19def8d..90d8a7953 100644
--- a/src/tests/app-smoke.test.ts
+++ b/src/tests/app-smoke.test.ts
@@ -129,6 +129,59 @@ test("loader sets all 4 GSD_ env vars and PI_PACKAGE_DIR", async (t) => {
   rmSync(tmp, { recursive: true, force: true });
 });
 
+// ═══════════════════════════════════════════════════════════════════════════
+// 2b. loader runtime dependency checks
+// ═══════════════════════════════════════════════════════════════════════════
+
+test("loader source contains Node version check with MIN_NODE_MAJOR", () => {
+  const loaderSrc = readFileSync(join(projectRoot, "src", "loader.ts"), "utf-8");
+  assert.ok(loaderSrc.includes("MIN_NODE_MAJOR"), "loader defines MIN_NODE_MAJOR constant");
+  assert.ok(loaderSrc.includes("process.versions.node"), "loader checks process.versions.node");
+});
+
+test("loader source contains git availability check", () => {
+  const loaderSrc = readFileSync(join(projectRoot, "src", "loader.ts"), "utf-8");
+  assert.ok(loaderSrc.includes("git"), "loader checks for git");
+  assert.ok(loaderSrc.includes("execFileSync"), "loader uses execFileSync for git check");
+});
+
+test("loader exits with error on unsupported Node version", () => {
+  // Spawn a subprocess that simulates the loader's version check logic
+  // with a deliberately high minimum to force the failure path
+  const script = [
+    "const major = parseInt(process.versions.node.split('.')[0], 10);",
+    "const MIN = 99;",
+    "if (major < MIN) { process.stderr.write('WOULD_EXIT'); process.exit(1); }",
+    "process.stdout.write('OK');",
+  ].join(" ");
+  try {
+    execSync(`node -e "${script}"`, { encoding: "utf-8", stdio: "pipe" });
+    // Node >= 99 would reach here — acceptable no-op
+  } catch (err: unknown) {
+    const e = err as { status?: number; stderr?: string };
+    assert.strictEqual(e.status, 1, "exits with code 1 for unsupported Node");
+    assert.ok((e.stderr || "").includes("WOULD_EXIT"), "stderr contains version error");
+  }
+});
+
+test("loader MIN_NODE_MAJOR matches package.json engines field", () => {
+  const loaderSrc = readFileSync(join(projectRoot, "src", "loader.ts"), "utf-8");
+  const pkg = JSON.parse(readFileSync(join(projectRoot, "package.json"), "utf-8"));
+
+  // Extract MIN_NODE_MAJOR value from loader source
+  const match = loaderSrc.match(/MIN_NODE_MAJOR\s*=\s*(\d+)/);
+  assert.ok(match, "MIN_NODE_MAJOR is defined with a numeric value");
+  const loaderMin = parseInt(match![1], 10);
+
+  // Extract major version from engines.node (e.g. ">=22.0.0" → 22)
+  const engineMatch = (pkg.engines?.node || "").match(/(\d+)/);
+  assert.ok(engineMatch, "package.json engines.node is defined");
+  const engineMin = parseInt(engineMatch![1], 10);
+
+  assert.strictEqual(loaderMin, engineMin,
+    `loader MIN_NODE_MAJOR (${loaderMin}) must match package.json engines.node (>=${engineMin}.0.0)`);
+});
+
 // ═══════════════════════════════════════════════════════════════════════════
 // 3. resource-loader syncs bundled resources
 // ═══════════════════════════════════════════════════════════════════════════