diff --git a/CHANGELOG.md b/CHANGELOG.md
index eec7e53..cd3095d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,5 +2,6 @@
 
 ## Unreleased
 
+- Add `--platform` to build smaller npm tarballs for one supported operating system and architecture while retaining the default universal package.
 - Preserve every scanner report when sanitized target, profile, or custom scanner names collide with each other or generated numeric suffixes.
 - Fix unbounded memory use when loading benchmark `--ids` from files or HTTP, including whitespace-padded IDs; document selection limits and preserve full-set JSONL support. Thanks @SebTardif (#47).
diff --git a/npm/README.md b/npm/README.md
new file mode 100644
index 0000000..6cd142c
--- /dev/null
+++ b/npm/README.md
@@ -0,0 +1,30 @@
+# Building npm packages
+
+The default build produces the universal `@openclaw/clawscan` package with all
+six supported binaries:
+
+```sh
+node scripts/build-npm-package.mjs --version v0.0.0 --pack --smoke
+```
+
+Use `--platform` to build a smaller tarball containing one binary. For example:
+
+```sh
+node scripts/build-npm-package.mjs --version v0.0.0 --platform linux-x64 --out dist/npm-linux-x64 --pack
+npm install --global ./dist/npm-linux-x64/openclaw-clawscan-linux-x64-0.0.0.tgz
+clawscan --version
+```
+
+Supported values are `darwin-x64`, `darwin-arm64`, `linux-x64`, `linux-arm64`,
+`win32-x64`, and `win32-arm64`. The package name is
+`@openclaw/clawscan-<platform>`, and its `os` and `cpu` fields restrict installation
+to that platform. Each package keeps the `clawscan` command and the
+`./resolve-binary` export, with its binary under `binaries/<platform>/`.
+
+Use a distinct `--out` directory to retain multiple builds; each build replaces
+its output directory. Add `--smoke` when building for the current host to install
+the tarball in a temporary prefix and run `--version` and a static scan.
+
+The platform-specific tarballs are local build artifacts. Registry publication
+still uses the universal package; publishing the additional names requires their
+registry bootstrap, trusted-publisher setup, and release-workflow integration.
diff --git a/scripts/build-npm-package.mjs b/scripts/build-npm-package.mjs
index 924ff62..261faaf 100755
--- a/scripts/build-npm-package.mjs
+++ b/scripts/build-npm-package.mjs
@@ -58,6 +58,17 @@ export function binaryNameForTarget(target) {
   return target.goos === "windows" ? "clawscan.exe" : "clawscan";
 }
 
+export function packageTargetForPlatform(platform) {
+  const target = packageTargets.find((entry) => platformKeyForTarget(entry) === platform);
+  if (!target) {
+    const supported = packageTargets.map(platformKeyForTarget).join(", ");
+    throw new Error(
+      `Unsupported npm package platform: ${platform ?? "<missing>"}. Expected ${supported}.`,
+    );
+  }
+  return target;
+}
+
 function run(command, args, options = {}) {
   const result = spawnSync(command, args, {
     cwd: options.cwd ?? repoRoot,
@@ -91,6 +102,10 @@ function parseArgs(argv) {
       options.outDir = resolve(argv[++index]);
       continue;
     }
+    if (arg === "--platform") {
+      options.target = packageTargetForPlatform(argv[++index]);
+      continue;
+    }
     if (arg === "--pack") {
       options.pack = true;
       continue;
@@ -132,10 +147,17 @@ async function stagePackage(options) {
   const packageJsonPath = join(packageOut, "package.json");
   const packageJson = JSON.parse(await readFile(packageJsonPath, "utf8"));
   packageJson.version = packageVersion;
+  if (options.target) {
+    const platformKey = platformKeyForTarget(options.target);
+    const [platform, arch] = platformKey.split("-");
+    packageJson.name = `${packageJson.name}-${platformKey}`;
+    packageJson.os = [platform];
+    packageJson.cpu = [arch];
+  }
   await writeFile(packageJsonPath, `${JSON.stringify(packageJson, null, 2)}\n`);
 
   const ldflags = `-s -w -X main.version=${binaryVersion} -X main.commit=${releaseCommit} -X main.date=${buildDate}`;
-  for (const target of packageTargets) {
+  for (const target of options.target ? [options.target] : packageTargets) {
     const binaryDir = join(packageOut, "binaries", platformKeyForTarget(target));
     await mkdir(binaryDir, { recursive: true });
     run(
@@ -164,20 +186,26 @@ async function stagePackage(options) {
   await writeFile(join(options.outDir, "release-sha.txt"), `${releaseSha}\n`);
   await writeFile(join(options.outDir, "package-version.txt"), `${packageVersion}\n`);
 
-  return { binaryVersion, packageOut, packageVersion, releaseSha };
+  return {
+    binaryVersion,
+    packageName: packageJson.name,
+    packageOut,
+    packageVersion,
+    releaseSha,
+  };
 }
 
-export function parsePackFilename(output) {
+export function parsePackFilename(output, packageName = "@openclaw/clawscan") {
   const parsed = JSON.parse(output);
   // npm 12 keys results by package name; older supported npm versions use an array.
-  const packed = Array.isArray(parsed) ? parsed[0] : parsed?.["@openclaw/clawscan"];
+  const packed = Array.isArray(parsed) ? parsed[0] : parsed?.[packageName];
   if (typeof packed?.filename !== "string" || !packed.filename) {
     throw new Error("npm pack did not return a tarball filename.");
   }
   return packed.filename;
 }
 
-async function packPackage(options, packageOut) {
+async function packPackage(options, packageOut, packageName) {
   const result = run(
     "npm",
     ["pack", "--json", "--ignore-scripts", "--pack-destination", options.outDir],
@@ -185,7 +213,7 @@ async function packPackage(options, packageOut) {
       cwd: packageOut,
     },
   );
-  return resolve(options.outDir, parsePackFilename(result.stdout));
+  return resolve(options.outDir, parsePackFilename(result.stdout, packageName));
 }
 
 async function smokePackage(tarballPath, binaryVersion) {
@@ -215,7 +243,7 @@ export async function main(argv = process.argv.slice(2)) {
   const staged = await stagePackage(options);
   let tarballPath = "";
   if (options.pack) {
-    tarballPath = await packPackage(options, staged.packageOut);
+    tarballPath = await packPackage(options, staged.packageOut, staged.packageName);
   }
   if (options.smoke) {
     await smokePackage(tarballPath, staged.binaryVersion);
diff --git a/scripts/build-npm-package.test.mjs b/scripts/build-npm-package.test.mjs
index b38f0ea..58d7f8e 100644
--- a/scripts/build-npm-package.test.mjs
+++ b/scripts/build-npm-package.test.mjs
@@ -3,10 +3,12 @@ import { readFileSync } from "node:fs";
 import { describe, it } from "node:test";
 import {
   binaryNameForTarget,
+  main,
   normalizeBuildDate,
   normalizePackageVersion,
   npmDistTagForVersion,
   packageTargets,
+  packageTargetForPlatform,
   parsePackFilename,
   platformKeyForTarget,
 } from "./build-npm-package.mjs";
@@ -22,6 +24,21 @@ describe("npm pack output", () => {
     assert.equal(parsePackFilename(JSON.stringify([{ filename }])), filename);
   });
 
+  it("reads the selected platform package from npm 11 and npm 12 results", () => {
+    const name = "@openclaw/clawscan-win32-arm64";
+    const platformFilename = "openclaw-clawscan-win32-arm64-1.2.3.tgz";
+    for (const result of [
+      { [name]: { filename: platformFilename } },
+      [{ filename: platformFilename }],
+    ]) {
+      assert.equal(parsePackFilename(JSON.stringify(result), name), platformFilename);
+    }
+    assert.throws(
+      () => parsePackFilename(JSON.stringify({ "@openclaw/clawscan": { filename } }), name),
+      /did not return a tarball filename/,
+    );
+  });
+
   it("rejects missing or invalid tarball filenames", () => {
     for (const result of [null, {}, [], [{ filename: "" }], { "@openclaw/clawscan": { filename: 42 } }]) {
       assert.throws(() => parsePackFilename(JSON.stringify(result)), /did not return a tarball filename/);
@@ -67,6 +84,28 @@ describe("normalizeBuildDate", () => {
 });
 
 describe("package target mapping", () => {
+  it("selects one Go target for each supported npm platform", () => {
+    for (const [platform, target] of [
+      ["darwin-x64", { goos: "darwin", goarch: "amd64" }],
+      ["darwin-arm64", { goos: "darwin", goarch: "arm64" }],
+      ["linux-x64", { goos: "linux", goarch: "amd64" }],
+      ["linux-arm64", { goos: "linux", goarch: "arm64" }],
+      ["win32-x64", { goos: "windows", goarch: "amd64" }],
+      ["win32-arm64", { goos: "windows", goarch: "arm64" }],
+    ]) {
+      assert.deepEqual(packageTargetForPlatform(platform), target);
+    }
+  });
+
+  it("rejects missing or unsupported --platform values before staging output", async () => {
+    for (const args of [[], ["freebsd-x64"], ["linux-ia32"], ["windows-x64"]]) {
+      await assert.rejects(
+        main(["--version", "v1.2.3", "--platform", ...args]),
+        /Unsupported npm package platform/,
+      );
+    }
+  });
+
   it("maps Go release targets to npm binary directories", () => {
     assert.deepEqual(
       packageTargets.map((target) => [target.goos, target.goarch, platformKeyForTarget(target)]),