type-safety
Type Safety
Playbook for moving invariants from runtime checks into the type system. Six techniques that work together to make illegal states unrepresentable and catch bugs at compile time instead of test time.
This is NOT a general TypeScript style guide. These techniques apply to:
- Domain model design
- SDK / library public APIs
- Discriminated unions with mutually exclusive shapes
- Entity ID modeling (task IDs, user IDs, etc.)
- Boundary hardening (input validation, DB reads, external API responses)
They do NOT belong in:
- Application glue code (route handlers, UI components)
- Scripts, migrations, one-off tooling
- Code where a runtime check is clearer and equally safe
- Codebases without an existing type discipline to build on
More from inkeep/team-skills
qa
Manual QA testing — verify features end-to-end as a user would, by all means necessary. Exhausts every local tool: browser (Playwright), Docker, ad-hoc scripts, REPL, dev servers. Mock-aware — mocked test coverage does not count. Proves real userOutcome at highest achievable fidelity. Blocked scenarios flow to /pr as pending human verification. Standalone or composable with /ship. Triggers: qa, qa test, manual test, test the feature, verify it works, exploratory testing, smoke test, end-to-end verification.
61spec
Drive an evidence-driven, iterative product+engineering spec process that produces a full PRD + technical spec (often as SPEC.md). Use when scoping a feature or product surface area end-to-end; defining requirements; researching external/internal prior art; mapping current system behavior; comparing design options; making 1-way-door decisions; negotiating scope; and maintaining a live Decision Log + Open Questions backlog. Triggers: spec, PRD, proposal, technical spec, RFC, scope this, design doc, end-to-end requirements, scope plan, tradeoffs, open questions.
54cold-email
Generate cold emails for B2B personas. Use when asked to write cold outreach, sales emails, or prospect messaging. Supports 19 persona archetypes (Founder-CEO, CTO, VP Engineering, CIO, CPO, Product Directors, VP CX, Head of Support, Support Ops, DevRel, Head of Docs, Technical Writer, Head of Community, VP Growth, Head of AI, etc.). Can generate first-touch and follow-up emails. When a LinkedIn profile URL is provided, uses Crustdata MCP to enrich prospect data (name, title, company, career history, recent posts) for deep personalization.
54docs
Write or update documentation for engineering changes — both product-facing (user docs, API reference, guides) and internal (architecture docs, runbooks, inline code docs). Builds a world model of what changed and traces transitive documentation consequences across all affected surfaces. Discovers and uses repo-specific documentation skills, style guides, and conventions. Standalone or composable with /ship. Triggers: docs, documentation, write docs, update docs, document the changes, product docs, internal docs, changelog, migration guide.
52implement
Convert SPEC.md to spec.json, craft the implementation prompt, and execute the iteration loop via subprocess. Use when converting specs to spec.json, preparing implementation artifacts, running the iteration loop, or implementing features autonomously. Triggers: implement, spec.json, convert spec, implementation prompt, execute implementation, run implementation.
52ship
Orchestrate any code change from requirements to review-ready branch — scope-calibrated from small fixes to full features. Composes /spec, /implement, and /research with depth that scales to the task: lightweight spec and direct implementation for bug fixes and config changes, full rigor for features. Produces tested, locally reviewed, documented code on a feature branch. The developer pushes the branch and creates the PR. Use for ALL implementation work regardless of perceived scope — the workflow adapts depth, never skips phases. Triggers: ship, ship it, feature development, implement end to end, spec to PR, implement this, fix this, let's implement, let's go with that, build this, make the change, full stack implementation, autonomous development.
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