diff --git a/npm/ast-grep b/npm/ast-grep
old mode 100644
new mode 100755
index bc32727d..b34841d6
--- a/npm/ast-grep
+++ b/npm/ast-grep
@@ -1,3 +1,149 @@
-echo "ast-grep shim file was executed. This file exists so that npm tries to create the binary. It should be replaced after the 'postinstall' script is executed."
-echo "Did your package manager execute the post-install script? (N.B. not all of them do)"
-exit 1
+#!/usr/bin/env node
+
+const { spawn } = require("node:child_process");
+const fs = require("fs");
+const path = require("path");
+
+const binaryName = process.platform === "win32" ? "ast-grep.exe" : "ast-grep";
+
+function detectPackageName() {
+  const { platform, arch } = process;
+
+  switch (platform) {
+    case "darwin":
+      if (arch === "arm64") return "@ast-grep/cli-darwin-arm64";
+      if (arch === "x64") return "@ast-grep/cli-darwin-x64";
+      break;
+    case "linux": {
+      const { MUSL, familySync } = require("detect-libc");
+      if (familySync() === MUSL) return null;
+      if (arch === "arm64") return "@ast-grep/cli-linux-arm64-gnu";
+      if (arch === "x64") return "@ast-grep/cli-linux-x64-gnu";
+      break;
+    }
+    case "win32":
+      if (arch === "arm64") return "@ast-grep/cli-win32-arm64-msvc";
+      if (arch === "ia32") return "@ast-grep/cli-win32-ia32-msvc";
+      if (arch === "x64") return "@ast-grep/cli-win32-x64-msvc";
+      break;
+    default:
+      break;
+  }
+
+  return null;
+}
+
+function failToLocateBinary(pkgName, originalError) {
+  const messages = ["Failed to locate the ast-grep native binary."];
+
+  if (pkgName) {
+    messages.push(`Expected package: ${pkgName}`);
+  } else {
+    messages.push(
+      "This platform does not have a published prebuilt ast-grep binary.",
+    );
+  }
+
+  if (originalError) {
+    messages.push(`Underlying error: ${originalError.message}`);
+  }
+
+  messages.push(
+    "If you are installing from npm, ensure optional dependencies are enabled (e.g. do not use --no-optional).",
+  );
+  messages.push(
+    "For local development, run `cargo build --release` before invoking this script.",
+  );
+
+  console.error(messages.join("\n"));
+  process.exit(1);
+}
+
+function resolveBinaryPath() {
+  const pkgName = detectPackageName();
+  let moduleError = null;
+
+  if (pkgName) {
+    try {
+      const pkgDir = path.dirname(
+        require.resolve(`${pkgName}/package.json`, { paths: [__dirname] }),
+      );
+      const candidate = path.join(pkgDir, binaryName);
+      if (fs.existsSync(candidate)) {
+        return { binaryPath: candidate, pkgName };
+      }
+    } catch (err) {
+      moduleError = err;
+    }
+  }
+
+  const releaseCandidate = path.join(
+    __dirname,
+    "..",
+    "target",
+    "release",
+    binaryName,
+  );
+  if (fs.existsSync(releaseCandidate)) {
+    return { binaryPath: releaseCandidate, pkgName: null };
+  }
+
+  const debugCandidate = path.join(
+    __dirname,
+    "..",
+    "target",
+    "debug",
+    binaryName,
+  );
+  if (fs.existsSync(debugCandidate)) {
+    return { binaryPath: debugCandidate, pkgName: null };
+  }
+
+  failToLocateBinary(pkgName, moduleError);
+}
+
+function attachChildLifecycle(child) {
+  child.on("error", (error) => {
+    console.error("Failed to execute ast-grep binary.");
+    console.error(error);
+    process.exit(1);
+  });
+
+  const signals = ["SIGINT", "SIGTERM", "SIGHUP"];
+  const forwarders = signals.map((signal) => {
+    const handler = () => {
+      if (child.killed) {
+        return;
+      }
+      try {
+        child.kill(signal);
+      } catch (_) {
+        // Ignore
+      }
+    };
+    process.on(signal, handler);
+    return { signal, handler };
+  });
+
+  child.on("exit", (code, signal) => {
+    forwarders.forEach(({ signal, handler }) => {
+      process.removeListener(signal, handler);
+    });
+
+    if (signal) {
+      process.kill(process.pid, signal);
+    } else {
+      process.exit(code == null ? 1 : code);
+    }
+  });
+}
+
+function main() {
+  const { binaryPath } = resolveBinaryPath();
+  const child = spawn(binaryPath, process.argv.slice(2), {
+    stdio: "inherit",
+  });
+  attachChildLifecycle(child);
+}
+
+main();
diff --git a/npm/package.json b/npm/package.json
index ecc4fb3c..dde705a7 100644
--- a/npm/package.json
+++ b/npm/package.json
@@ -20,15 +20,11 @@
   ],
   "files": [
     "sg",
-    "ast-grep",
-    "postinstall.js"
+    "ast-grep"
   ],
   "dependencies": {
     "detect-libc": "2.1.2"
   },
-  "scripts": {
-    "postinstall": "node postinstall.js"
-  },
   "optionalDependencies": {
     "@ast-grep/cli-win32-arm64-msvc": "0.42.1",
     "@ast-grep/cli-win32-ia32-msvc": "0.42.1",
diff --git a/npm/postinstall.js b/npm/postinstall.js
deleted file mode 100644
index 884420a4..00000000
--- a/npm/postinstall.js
+++ /dev/null
@@ -1,49 +0,0 @@
-let fs = require('fs');
-let path = require('path');
-
-let parts = [process.platform, process.arch];
-if (process.platform === 'linux') {
-  const {MUSL, familySync} = require('detect-libc');
-  if (familySync() === MUSL) {
-    parts.push('musl');
-  } else if (process.arch === 'arm') {
-    parts.push('gnueabihf');
-  } else {
-    parts.push('gnu');
-  }
-} else if (process.platform === 'win32') {
-  parts.push('msvc');
-}
-
-let binary = process.platform === 'win32' ? 'ast-grep.exe' : 'ast-grep';
-let alternative = process.platform === 'win32' ? 'sg.exe' : 'sg';
-
-let pkgPath;
-try {
-  pkgPath = path.dirname(require.resolve(`@ast-grep/cli-${parts.join('-')}/package.json`));
-} catch (err) {
-  pkgPath = path.join(__dirname, '..', 'target', 'release');
-  if (!fs.existsSync(path.join(pkgPath, binary))) {
-    pkgPath = path.join(__dirname, '..', 'target', 'debug');
-  }
-}
-
-try {
-  fs.linkSync(path.join(pkgPath, binary), path.join(__dirname, binary));
-  fs.linkSync(path.join(pkgPath, binary), path.join(__dirname, alternative));
-} catch (err) {
-  try {
-    fs.copyFileSync(path.join(pkgPath, binary), path.join(__dirname, binary));
-    fs.copyFileSync(path.join(pkgPath, binary), path.join(__dirname, alternative));
-  } catch (err) {
-    console.error('Failed to move @ast-grep/cli binary into place.');
-    process.exit(1);
-  }
-}
-
-if (process.platform === 'win32') {
-  try {
-    fs.unlinkSync(path.join(__dirname, 'sg'));
-    fs.unlinkSync(path.join(__dirname, 'ast-grep'));
-  } catch (err) {}
-}
diff --git a/npm/sg b/npm/sg
old mode 100644
new mode 100755
index db345574..900a23c2
--- a/npm/sg
+++ b/npm/sg
@@ -1,2 +1,2 @@
-This file is required so that dumb npm creates the sg binary.
-N.B. pnpm does not have this issue.
+#!/usr/bin/env node
+require("./ast-grep");