Disciplined diagnosis loop for hard bugs and performance regressions. Reproduce → minimise → hypothesise → instrument → fix → regression-test. Use when user says "diagnose this" / "debug this", reports a bug, says something is broken/throwing/failing, or describes a performance regression.
Co-create an explicitly accepted, uncompromising destination before planning or implementation. Use when the user wants to discover what they actually want, asks for an uncompromising vision, wants iterative synthesis and pushback, is exploring an architecture or product model before a plan exists, or says to use dialectic. Do not use for interrogating an existing plan, comparing one bounded implementation choice, or ordinary implementation with a settled destination.
Factory function patterns to compose clients and services. Use when wrapping resources with domain methods or refactoring mixed client/service/method options.
Git commits and branches using Epicenter conventions. Use when staging files, writing commit messages, splitting commits, checking standalone commits, creating branches, or inspecting commit history. For pull request titles and bodies, use the pull-request skill.
Write and edit in GOV.UK / GDS house style: plain English, active voice, front-loaded content, sentence case, and no bold or italics for emphasis. Use when the user asks for GOV.UK or GDS style, or when writing reports, research write-ups, or guidance for external readers. Not for repo docs, UI strings, commit messages, or code comments; those follow writing-voice.
Greenfield clean-break review and execution for starting from an uncompromised target vision, working backward to deletion waves and owner changes, reopening settled decisions, refusing compatibility, collapsing old and new paths, moving ownership boundaries, replacing APIs, redesigning from first principles, and surfacing refusal candidates that delete disproportionate complexity. Use when the user says greenfield clean break, greenfield, clean break, no users, no compatibility burden, refuse compatibility, remove slop, collapse this, replace the API, trace upward, pressure-test the architecture, or asks whether old behavior can be deleted.
Hono patterns for TypeScript API routes, middleware, request and response typing, streaming, WebSockets, and Cloudflare Workers deployment. Use when users mention Hono, honojs, Cloudflare Worker handlers, Hono middleware, or Hono route typing.
Method shorthand in return objects for JSDoc preservation. Use when factory functions have internal helpers that should expose docs, or hovering over returned methods shows no JSDoc.
Monorepo scripts, package boilerplate, conventions. Use when: "how do I run", "bun run", "build this", "run tests", "typecheck", "create a new package", linting, scaffolding packages.