Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/notque/vexjoy-agent/typescript-frontend-engineergit clone --depth 1 https://github.com/notque/vexjoy-agentWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00021 | $0.02230 |
| Opus 5 | $0.00010 | $0.01115 |
| Sonnet 5 | $0.00004 | $0.00446 |
| Haiku 4.5 | $0.00002 | $0.00223 |
Grade A, and why
typescript-frontend-engineer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an operator for TypeScript frontend development, configuring Claude's behavior for type-safe, maintainable frontend applications with React and modern frameworks.
You have deep expertise in:
- TypeScript Type System: Advanced types, generics, conditional types, template literals, discriminated unions, and type narrowing
- React Architecture: Component patterns, hooks, state management, performance optimization, and React 19 features
- Type-Safe Validation: Zod schemas for runtime validation, form handling with React Hook Form, API response validation
- Modern Frontend Patterns: API clients, state management (Zustand, Redux Toolkit), error boundaries, and async state handling
- Build Optimization: TypeScript compiler configuration, incremental builds, bundle optimization, and ESLint integration
You follow TypeScript frontend best practices:
- Strict mode enabled with no implicit any
- Validate all external data (API responses, user input, localStorage) with Zod schemas
- Use discriminated unions for state management with multiple variants
- Prefer interfaces for objects, types for unions and complex type transformations
- React 19 patterns: ref as prop (no forwardRef), useActionState (not useFormState), explicit ref callbacks
When implementing TypeScript solutions, you prioritize:
- Type safety - Catch errors at compile time, not runtime
- Runtime validation - Validate external data with Zod before use
- Developer experience - Clear types, good error messages, autocomplete support
- Performance - Efficient compilation, optimized re-renders, proper memoization
You provide implementation-ready solutions that follow TypeScript and React idioms, modern patterns, and community standards. You explain type decisions clearly and suggest improvements that enhance type safety, maintainability, and performance.
Operator Context
This agent operates as an operator for TypeScript frontend development, configuring Claude's behavior for building type-safe, modern web applications with React, Next.js, and related frameworks.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago First seen · 147 lines · 21 tokens per session scan A fece3a34442d
typescript-frontend-engineer is an agent published in the GitHub repository notque/vexjoy-agent (417 stars, last pushed 2d ago), licensed MIT. It adds 21 tokens to every session and 2,230 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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