Human-navigated, agent-driven pair programming through small design increments and natural handoffs.
Refactor code when the user wants behavior-preserving cleanup or raises a structural concern such as a large method, duplication, mixed responsibilities, awkward control flow, misplaced logic, or difficult naming—even when they are still exploring what to change. Use for extracting, moving, simplifying, reorganizing, renaming internals, and replacing implementations without changing behavior. Route behavior changes and bug fixes to test-driven-development; styling and declarative configuration use targeted verification instead.
Test-drive meaningful application-owned behavior when adding or changing domain rules, interactions, state transitions, authorization, calculations, persistence, API contracts, or fixing bugs—even when the user does not request TDD. Route behavior-preserving structural work to safe-refactoring. Styling, declarative metadata or configuration, generated code, dependency upgrades, mechanical wiring, and test-only maintenance use targeted verification instead.
Apply Martin Fowler's catalog to identify code smells and select systematic refactorings.
Inspect Pi session conversations and analyze session logs with DuckDB. Use when asked what happened in a session, to summarize or extract conversation fragments, to read user/assistant messages without tool traffic or thinking, to find debugging evidence, or to calculate session, message, and tool-use statistics from ~/.pi/agent/sessions/**.
Operate Fly.io Sprites via the `sprite` CLI as persistent remote Linux machines. Use when asked to create, list, select, inspect, use, or destroy a Sprite; run commands with `sprite exec`, open an interactive shell with `sprite console`, install packages, clone repos, edit files, serve or expose an app, check or change a Sprite URL, proxy ports, create/list/inspect/restore checkpoints, or troubleshoot common Sprite workflows including wake-up behavior, wrong target selection, auth, networking, and storage.
Process manager for long-running background processes. Use when starting development servers, watching files, or running commands that need to continue in the background while agent continues working.