Guide for changing or extending Pi behaviour and building Pi Coding Agent extensions. Use when modifying how Pi behaves, choosing among Agent Skills vs extensions vs prompts/themes/packages, scaffolding or packaging an extension, creating custom tools/commands/hooks/providers/UI, intercepting tool calls, debugging extensions, or deciding whether a core Pi patch is needed. Also use for TypeScript extension work (ExtensionAPI, pi.registerTool, pi.on).
Pragmatic internal-logic style for small, readable, defensive code. Use when reviewing or writing backend logic, React components, hooks, or state management, or when the user mentions guard clauses, parse don't validate, illegal states, fail fast, pure functions, or intentional naming.
Generate multiple radically different interface designs for a module using parallel sub-agents. Use when user wants to design an API, explore interface options, compare module shapes, or mentions "design it twice".
Manage Todoist tasks via the `todoist` CLI tool. Use when the user asks to add, list, modify, close, delete, or filter tasks, or to inspect projects/labels. Covers task CRUD, filtering with Todoist filter syntax, quick add, project and label management, and completed tasks. Triggers on mentions of todoist, tasks, todos, to-do list, or task management via CLI.