diff --git a/src/server/services/ai-filtering.ts b/src/server/services/ai-filtering.ts
index 7ab667f..7aa42d3 100644
--- a/src/server/services/ai-filtering.ts
+++ b/src/server/services/ai-filtering.ts
@@ -796,6 +796,19 @@ export async function executeFilteringRules(
     let hasFailed = false
     let hasFlagged = false
 
+    // Built-in hard check: projects with zero files always fail
+    const fileCount = project.files?.length ?? 0
+    if (fileCount === 0) {
+      ruleResults.push({
+        ruleId: '__builtin_zero_files',
+        ruleName: 'Required Documents Check',
+        ruleType: 'DOCUMENT_CHECK',
+        passed: false,
+        action: 'REJECT',
+      })
+      hasFailed = true
+    }
+
     for (const rule of nonAiRules) {
       let result: { passed: boolean; action: 'PASS' | 'REJECT' | 'FLAG' }
       if (rule.ruleType === 'FIELD_BASED') {