diff --git a/build.ts b/build.ts
index 5ebc1e95f..cb28fd106 100644
--- a/build.ts
+++ b/build.ts
@@ -136,3 +136,16 @@ chmodSync(cliBun, 0o755)
 chmodSync(cliNode, 0o755)
 
 console.log(`Generated ${cliBun} (shebang: bun) and ${cliNode} (shebang: node)`)
+
+// Step 6: Clean up source maps — they add ~64MB to the package, exceeding
+// npmmirror's 80MB size limit. Source maps are only useful for local
+// debugging, not for package consumers.
+const { unlinkSync } = await import('fs')
+let mapCount = 0
+for (const file of files) {
+  if (file.endsWith('.map')) {
+    unlinkSync(join(outdir, file))
+    mapCount++
+  }
+}
+console.log(`Cleaned ${mapCount} source map files from ${outdir}/ (saved ~64MB)`)
diff --git a/package.json b/package.json
index b9491cfc2..e5d1ec370 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@costrict/csc",
-  "version": "4.0.15",
+  "version": "4.0.16",
   "description": "costrict",
   "type": "module",
   "author": "costrict",
diff --git a/scripts/defines.ts b/scripts/defines.ts
index 3f731fbd6..c8bc60c9f 100644
--- a/scripts/defines.ts
+++ b/scripts/defines.ts
@@ -14,7 +14,7 @@ export function getMacroDefines(): Record<string, string> {
         // ignore git errors
     }
     return {
-        "MACRO.VERSION": JSON.stringify("4.0.15"),
+        "MACRO.VERSION": JSON.stringify("4.0.16"),
         "MACRO.BUILD_TIME": JSON.stringify(new Date().toISOString()),
         "MACRO.COMMIT": JSON.stringify(commit),
         "MACRO.FEEDBACK_CHANNEL": JSON.stringify(""),