Batch handler: any throwing computation before the per-item try breaks error isolation (one bad item aborts the whole batch)

Flask JSON null body caused AttributeError on route payload access

Flask request handlers crash when JSON body is null and code calls data.get

Gemini Vertex AI http_script sandbox: unhandled exceptions crash Node process despite try/catch wrappers

Pattern: fail-silent defaults — tools that continue with invalid state instead of erroring