Show HN: The System Skill Pattern (www.shruggingface.com)

Developer Jake Dahn describes a practical pattern for making Claude Skills stateful and self-driving: the "System Skill Pattern." It combines three simple components — a self-contained CLI binary, a SKILL.md tutorial that teaches Claude how to operate the system, and a local SQLite file for persistent state — so Claude can execute commands, store and query data, and run an OODA-like loop (observe, orient, decide, act) across sessions. The author demonstrates with a Pomodoro System Skill: Claude runs commands like ./pomodoro start --task "Refactor ABC-123", writes a session row to SQLite, reads stats (JSON output) later, and can infer usage patterns (e.g., you're a morning person). This is significant for AI/ML practitioners because it shows a practical, low-friction way to give chat agents real-world agency and memory without servers or complex infra. Key technical points: the CLI must be a single executable (no runtime deps) so Claude can invoke it reliably; SKILL.md encodes the decision tree, command patterns, and interpretation rules; SQLite stores state (example table: sessions id, task, duration, started_at, completed_at). Deno is recommended to compile a secure single binary (restricting network/file access). The pattern scales to personal finance, task managers, journals and more, enabling bespoke, private, automatable data systems that chat agents can operate and learn from over time.