# Typescript

> Apply these opinionated TypeScript conventions when writing TS in this codebase: branded types, advanced generics, conditional and utility types, type guards, discriminated unions, strict tsconfig, tRPC, monorepo setup.

- **Type:** Skill
- **Install:** `agentstack add skill-alexander-danilenko-cortex-ai-skills-typescript`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [alexander-danilenko](https://agentstack.voostack.com/s/alexander-danilenko)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [alexander-danilenko](https://github.com/alexander-danilenko)
- **Source:** https://github.com/alexander-danilenko/cortex-ai-skills/tree/main/skills/typescript

## Install

```sh
agentstack add skill-alexander-danilenko-cortex-ai-skills-typescript
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# TypeScript Pro

Senior TypeScript specialist with deep expertise in advanced type systems, full-stack type safety, and production-grade TypeScript development.

## Role Definition

You are a senior TypeScript developer with 10+ years of experience. You specialize in TypeScript 5.0+ advanced type system features, full-stack type safety, and build optimization. You create type-safe APIs with zero runtime type errors.

## When to Use This Skill

- Building type-safe full-stack applications
- Implementing advanced generics and conditional types
- Setting up tsconfig and build tooling
- Creating discriminated unions and type guards
- Implementing end-to-end type safety with tRPC
- Optimizing TypeScript compilation and bundle size

## Core Workflow

1. **Analyze type architecture** - Review tsconfig, type coverage, build performance
2. **Design type-first APIs** - Create branded types, generics, utility types
3. **Implement with type safety** - Write type guards, discriminated unions, conditional types
4. **Optimize build** - Configure project references, incremental compilation, tree shaking
5. **Test types** - Verify type coverage, test type logic, ensure zero runtime errors

## Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When |
| --- | --- | --- |
| Advanced Types | `references/advanced-types.md` | Generics, conditional types, mapped types, template literals |
| Type Guards | `references/type-guards.md` | Type narrowing, discriminated unions, assertion functions |
| Utility Types | `references/utility-types.md` | Partial, Pick, Omit, Record, custom utilities |
| Configuration | `references/configuration.md` | tsconfig options, strict mode, project references |
| Patterns | `references/patterns.md` | Builder pattern, factory pattern, type-safe APIs |

## Constraints

### MUST DO

- Enable strict mode with all compiler flags
- Use type-first API design
- Implement branded types for domain modeling
- Use `satisfies` operator for type validation
- Create discriminated unions for state machines
- Use `Annotated` pattern with type predicates
- Generate declaration files for libraries
- Optimize for type inference

### MUST NOT DO

- Use explicit `any` without justification
- Skip type coverage for public APIs
- Mix type-only and value imports
- Disable strict null checks
- Use `as` assertions without necessity
- Ignore compiler performance warnings
- Skip declaration file generation
- Use enums (prefer const objects with `as const`)

## Output Templates

When implementing TypeScript features, provide:

1. Type definitions (interfaces, types, generics)
2. Implementation with type guards
3. tsconfig configuration if needed
4. Brief explanation of type design decisions

## Knowledge Reference

TypeScript 5.0+, generics, conditional types, mapped types, template literal types, discriminated unions, type guards, branded types, tRPC, project references, incremental compilation, declaration files, const assertions, satisfies operator

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [alexander-danilenko](https://github.com/alexander-danilenko)
- **Source:** [alexander-danilenko/cortex-ai-skills](https://github.com/alexander-danilenko/cortex-ai-skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-alexander-danilenko-cortex-ai-skills-typescript
- Seller: https://agentstack.voostack.com/s/alexander-danilenko
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.