fix(sandbox): consistency and cleanup pass on doc-gen tasks and worker

- DOCX addImage: upfront width/height validation (matches PDF/PPTX pattern)
- PDF embedImage: remove dead Buffer ternary; drop redundant size guard already enforced in getFileBase64
- isolated-vm-worker: add friendly MemoryLimitError branch in both execute paths so OOM produces a clear message instead of a raw V8 error

Author: waleedlatif1

apps/sim/lib/execution/isolated-vm-worker.cjs

@@ -398,6 +398,21 @@ async function executeCode(request, executionId) {
         }
       }
 
+      if (
+        err.message.includes('Array buffer allocation failed') ||
+        err.message.includes('memory limit')
+      ) {
+        return {
+          result: null,
+          stdout,
+          error: {
+            message:
+              'Execution exceeded memory limit (256 MB). Reduce image sizes or split the work into smaller batches.',
+            name: 'MemoryLimitError',
+          },
+        }
+      }
+
       return {
         result: null,
         stdout,
@@ -937,6 +952,23 @@ async function executeTask(request, executionId) {
           timings,
         }
       }
+
+      if (
+        err.message?.includes('Array buffer allocation failed') ||
+        err.message?.includes('memory limit')
+      ) {
+        return {
+          result: null,
+          stdout,
+          error: {
+            message:
+              'Execution exceeded memory limit (256 MB). Reduce image sizes or split the work into smaller batches.',
+            name: 'MemoryLimitError',
+          },
+          timings,
+        }
+      }
+
       return {
         result: null,
         stdout,

apps/sim/sandbox-tasks/docx-generate.ts

@@ -53,6 +53,9 @@ export const docxGenerateTask = defineSandboxTask<SandboxTaskInput>({
      *   new docx.Paragraph({ children: [await addImage('abc123', { width: 200, height: 100 })] })
      */
     globalThis.addImage = async function addImage(fileId, opts) {
+      if (!opts || opts.width == null || opts.height == null) {
+        throw new Error('addImage: opts must include width and height (in pixels)');
+      }
       const dataUri = await globalThis.getFileBase64(fileId);
       const comma = dataUri.indexOf(',');
       if (comma === -1) throw new Error('addImage: invalid data URI (no comma separator)');
@@ -63,11 +66,11 @@ export const docxGenerateTask = defineSandboxTask<SandboxTaskInput>({
       const ext = extMap[mime];
       if (!ext) throw new Error('addImage: unsupported image type "' + mime + '". Use PNG, JPEG, GIF, BMP, or SVG.');
       if (!globalThis.Buffer) throw new Error('addImage: Buffer polyfill missing — ensure docx bundle is loaded');
-      const { width, height, type: _t, data: _d, transformation: userTransform, ...passThrough } = opts || {};
+      const { width, height, type: _t, data: _d, transformation: userTransform, ...passThrough } = opts;
       return new globalThis.docx.ImageRun(Object.assign(passThrough, {
         data: globalThis.Buffer.from(base64, 'base64'),
         type: ext,
-        transformation: Object.assign({ width: width ?? 200, height: height ?? 200 }, userTransform || {}),
+        transformation: Object.assign({ width, height }, userTransform || {}),
       }));
     };
   `,

apps/sim/sandbox-tasks/pdf-generate.ts

@@ -32,17 +32,12 @@ export const pdfGenerateTask = defineSandboxTask<SandboxTaskInput>({
       if (!dataUri || typeof dataUri !== 'string') {
         throw new Error('embedImage: dataUri must be a non-empty string');
       }
-      if (dataUri.length > _MAX_IMG_B64) {
-        throw new Error(
-          'embedImage: image exceeds the 6 MB embed limit (~8 MB base64). Use a smaller/compressed image.'
-        );
-      }
       const comma = dataUri.indexOf(',');
       if (comma === -1) throw new Error('embedImage: invalid data URI (no comma separator)');
       const header = dataUri.slice(0, comma);
       const base64 = dataUri.slice(comma + 1);
-      const binary = globalThis.Buffer ? globalThis.Buffer.from(base64, 'base64') : null;
-      if (!binary) throw new Error('Buffer polyfill missing');
+      if (!globalThis.Buffer) throw new Error('embedImage: Buffer polyfill missing');
+      const binary = globalThis.Buffer.from(base64, 'base64');
       const mime = header.split(';')[0].split(':')[1] || '';
       // image/jpg is non-standard but tolerated; the canonical MIME is image/jpeg
       if (mime === 'image/png') return globalThis.pdf.embedPng(binary);