Falco is a cloud-native runtime security daemon that monitors Linux system calls, Kubernetes audit logs, and plugin-supplied events in real time. It applies a flexible rule engine to detect anomalous behavior and generates alerts via multiple output channels (stdout, file, syslog, HTTP, program). The codebase is a monolithic C++ application with a modular internal architecture: a sequenced action pipeline (app/app.cpp) drives startup, configuration, plugin loading, rule compilation, event processing, and output dispatch. The rule engine (userspace/engine/) parses YAML rule definitions, resolves macros and filters, indexes rules by event type, and matches events efficiently. The output subsystem uses a thread-safe worker queue with a watchdog. Falco supports hot-reload via inotify file watching and a Unix socket control endpoint. It is deployed as a Helm chart on Kubernetes (DaemonSet/Deployment) and is packaged as DEB, RPM, and Docker images. The repository includes extensive unit tests (Google Test), end-to-end event generator tests, and CI/CD pipelines for building, testing, and publishing. External dependencies include falcosecurity/libs (sinsp), falcoctl, OpenSSL, cURL, yaml-cpp, and jemalloc. The architecture demonstrates strong engineering practices with clean abstractions (indexed_vector, atomic_signal_handler, yaml_helper) and composable action steps.