Master nushell (`nu`) — the structured-data shell and language — for writing scripts, modules, custom commands, manipulating tables/records/lists through pipelines, configuring the environment, and working with files, HTTP, and external commands. Use whenever the user mentions nushell, nu, .nu files, config.nu, env.nu, or wants to write shell scripts in a structured-data paradigm. Trigger for pipeline data transformations, filtering/grouping tables, def/module/overlay authoring, porting bash to nushell, or working with JSON/CSV/YAML from the command line. Do not use for bash, zsh, POSIX shell, PowerShell, or fish.
Master SolidJS development — reactive primitives, components, routing, SSR, SolidStart, stores, and architecture. Use when building SolidJS apps, debugging Solid reactivity, or making architectural decisions in Solid projects.
Master neverthrow for TypeScript — Result/ResultAsync types, railway-oriented error handling, ok/err/okAsync/errAsync constructors, map/andThen/match/orElse/combine combinators, safeTry, and best practices for separating expected recoverable errors from unexpected bugs. Use this skill whenever the user mentions neverthrow, Result or ResultAsync types, functional or railway-oriented error handling in TypeScript, "instead of try/catch", "Rust-style errors in TS", ok()/err(), map vs andThen, combine, or wants typed error handling that doesn't throw. Trigger even if the user doesn't name neverthrow but asks for typed Result-style error handling in a TS/JS codebase. Do not use for Effect, fp-ts Either, or triple.js.