Skill: otp-patterns

INVOKE BEFORE implementing or reviewing OTP components (Application, Supervisor, GenServer, Registry, DynamicSupervisor).

Use when

• Adding or modifying supervised processes.
• Designing registries/dynamic supervisors.
• Debugging GenServer callbacks or timeouts.

Checklist

• Separate client/API vs server callbacks.
• Add @impl true to callbacks; pattern match on messages.
• Avoid blocking in callbacks; offload to Tasks or async streams.
• Supervision: choose the lightest strategy (one_for_one default).
• Register via Registry or {via, Registry, ...} instead of global names.
• Instrument with telemetry events for critical paths.

Quick snippets

• Start child: Supervisor.start_child/2 for static; DynamicSupervisor.start_child/2 for dynamic.
• Timeout hygiene: handle_call should avoid long work; use async reply when necessary.

References

• ai-rules: patterns/otp/ if present; follow BEAMAI defaults.