diff --git a/package.json b/package.json
index 221d428ec..1e4e60150 100644
--- a/package.json
+++ b/package.json
@@ -75,7 +75,24 @@
   "devDependencies": {
     "@boneskull/typedoc-plugin-mermaid": "^0.2.0",
     "@modelcontextprotocol/sdk": "1.25.2",
+    "@oven/bun-darwin-aarch64": "^1.2.21",
+    "@oven/bun-darwin-x64": "^1.2.21",
+    "@oven/bun-darwin-x64-baseline": "^1.2.21",
+    "@oven/bun-linux-aarch64": "^1.2.21",
+    "@oven/bun-linux-aarch64-musl": "^1.2.21",
+    "@oven/bun-linux-x64": "^1.2.21",
+    "@oven/bun-linux-x64-baseline": "^1.2.21",
+    "@oven/bun-linux-x64-musl": "^1.2.21",
+    "@oven/bun-linux-x64-musl-baseline": "^1.2.21",
+    "@oven/bun-windows-x64": "^1.2.21",
+    "@oven/bun-windows-x64-baseline": "^1.2.21",
     "@playwright/test": "1.57.0",
+    "@rollup/rollup-darwin-arm64": "^4.53.3",
+    "@rollup/rollup-darwin-x64": "^4.53.3",
+    "@rollup/rollup-linux-arm64-gnu": "^4.53.3",
+    "@rollup/rollup-linux-x64-gnu": "^4.53.3",
+    "@rollup/rollup-win32-arm64-msvc": "^4.53.3",
+    "@rollup/rollup-win32-x64-msvc": "^4.53.3",
     "@types/bun": "^1.3.2",
     "@types/react": "^19.2.2",
     "@types/react-dom": "^19.2.2",
@@ -117,25 +134,6 @@
       "optional": true
     }
   },
-  "optionalDependencies": {
-    "@oven/bun-darwin-aarch64": "^1.2.21",
-    "@oven/bun-darwin-x64": "^1.2.21",
-    "@oven/bun-darwin-x64-baseline": "^1.2.21",
-    "@oven/bun-linux-aarch64": "^1.2.21",
-    "@oven/bun-linux-aarch64-musl": "^1.2.21",
-    "@oven/bun-linux-x64": "^1.2.21",
-    "@oven/bun-linux-x64-baseline": "^1.2.21",
-    "@oven/bun-linux-x64-musl": "^1.2.21",
-    "@oven/bun-linux-x64-musl-baseline": "^1.2.21",
-    "@oven/bun-windows-x64": "^1.2.21",
-    "@oven/bun-windows-x64-baseline": "^1.2.21",
-    "@rollup/rollup-darwin-arm64": "^4.53.3",
-    "@rollup/rollup-darwin-x64": "^4.53.3",
-    "@rollup/rollup-linux-arm64-gnu": "^4.53.3",
-    "@rollup/rollup-linux-x64-gnu": "^4.53.3",
-    "@rollup/rollup-win32-arm64-msvc": "^4.53.3",
-    "@rollup/rollup-win32-x64-msvc": "^4.53.3"
-  },
   "overrides": {
     "seroval": "1.4.1",
     "seroval-plugins": "1.4.2",
diff --git a/scripts/setup-bun.mjs b/scripts/setup-bun.mjs
index 3314cacca..5ea211cff 100644
--- a/scripts/setup-bun.mjs
+++ b/scripts/setup-bun.mjs
@@ -1,7 +1,4 @@
 #!/usr/bin/env node
-// Immediate log to verify script execution
-console.log("[setup-bun] Script loaded");
-
 /**
  * Postinstall script to set up bun from platform-specific optional dependencies.
  * Handles Windows ARM64 by downloading x64-baseline via emulation.
@@ -16,7 +13,7 @@ import {
   writeFileSync,
   statSync,
 } from "fs";
-import { join, dirname } from "path";
+import { join, dirname, resolve } from "path";
 import { spawnSync } from "child_process";
 import { fileURLToPath } from "url";
 import { get } from "https";
@@ -24,6 +21,15 @@ import { createGunzip } from "zlib";
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const projectRoot = join(__dirname, "..");
+
+// Skip when installed as a dependency (INIT_CWD is the user's project directory,
+// not the package root). Bun is a dev-only build tool not needed by SDK consumers.
+if (process.env.INIT_CWD && resolve(process.env.INIT_CWD) !== resolve(projectRoot)) {
+  process.exit(0);
+}
+
+// Immediate log to verify script execution
+console.log("[setup-bun] Script loaded");
 const nodeModules = join(projectRoot, "node_modules");
 const binDir = join(nodeModules, ".bin");