diff --git a/backend/routes/ivantiFpWorkflow.js b/backend/routes/ivantiFpWorkflow.js
index 523ad32..38947b4 100644
--- a/backend/routes/ivantiFpWorkflow.js
+++ b/backend/routes/ivantiFpWorkflow.js
@@ -260,6 +260,12 @@ function createIvantiFpWorkflowRouter() {
                     const foundIds = new Set(libraryDocs.map(d => d.id));
                     const missingIds = libraryDocIds.filter(id => !foundIds.has(id));
                     if (missingIds.length > 0) return res.status(400).json({ error: `Library document IDs not found: ${missingIds.join(', ')}` });
+                    // Validate file types for library docs (same rules as local uploads)
+                    const unsupportedDocs = libraryDocs.filter(d => !isAllowedFileExtension(d.name));
+                    if (unsupportedDocs.length > 0) {
+                        const names = unsupportedDocs.map(d => d.name).join(', ');
+                        return res.status(400).json({ error: `Library document file type not supported by Ivanti: ${names}. Allowed: ${[...ALLOWED_EXTENSIONS].join(', ')}` });
+                    }
                 }
 
                 const libraryFormFiles = [];
@@ -821,6 +827,12 @@ function createIvantiFpWorkflowRouter() {
                     const foundIds = new Set(libraryDocs.map(d => d.id));
                     const missingIds = libraryDocIds.filter(id => !foundIds.has(id));
                     if (missingIds.length > 0) return res.status(400).json({ error: `Library document IDs not found: ${missingIds.join(', ')}` });
+                    // Validate file types for library docs
+                    const unsupportedDocs = libraryDocs.filter(d => !isAllowedFileExtension(d.name));
+                    if (unsupportedDocs.length > 0) {
+                        const names = unsupportedDocs.map(d => d.name).join(', ');
+                        return res.status(400).json({ error: `Library document file type not supported by Ivanti: ${names}. Allowed: ${[...ALLOWED_EXTENSIONS].join(', ')}` });
+                    }
                 }
 
                 const apiKey = process.env.IVANTI_API_KEY;