typescript-engineering

typescript-engineering is a skill for Claude Code, Codex from mfmezger/ai_agent_dotfiles. It costs 122 tokens per session (874 once invoked), scanned A, original, MIT.

A set of guidelines for writing, reviewing, refactoring, and debugging TypeScript, the programming language that adds type checking to JavaScript.

In plain words
What is it for?
Use it for TypeScript or TSX code, API design, strict compiler settings, generic and union types, type narrowing, runtime validation, and running formatters, linters, type checks, and tests.
Why use it?
It helps keep data boundaries, failure cases, asynchronous work, and public interfaces clear and checked before code is finalized.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for TypeScript or TSX code, API design, strict compiler settings, generic and union types, type narrowing, runtime validation, and running formatters, linters, type checks, and tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mfmezger/ai_agent_dotfiles/typescript-engineering
Install

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.

Any agent
npx skills add mfmezger/ai_agent_dotfiles --skill typescript-engineering
Clone the repo
git clone --depth 1 https://github.com/mfmezger/ai_agent_dotfiles

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for typescript-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/mfmezger/ai_agent_dotfiles/typescript-engineering/github.svg)](https://agentmods.dev/skills/mfmezger/ai_agent_dotfiles/typescript-engineering)
Your own site
<a href="https://agentmods.dev/skills/mfmezger/ai_agent_dotfiles/typescript-engineering"><img src="https://agentmods.dev/badge/skills/mfmezger/ai_agent_dotfiles/typescript-engineering/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for typescript-engineering

Your own site · 80×15
<a href="https://agentmods.dev/skills/mfmezger/ai_agent_dotfiles/typescript-engineering"><img src="https://agentmods.dev/badge/skills/mfmezger/ai_agent_dotfiles/typescript-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 122 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 874 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00122 $0.00874
Opus 5.5 $0.00049 $0.00350
Sonnet 5.5 $0.00024 $0.00175
Haiku 4.5 $0.00012 $0.00087

Measured 1mo ago against content hash 0f8d0f26c3a9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

typescript-engineering 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 1mo 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.

shared/skills/typescript-engineering/SKILL.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TypeScript Engineering

Produce TypeScript that is explicit at boundaries, narrow in surface area, and strict enough that refactors fail fast. Prefer inference inside small scopes, explicit types at module boundaries, runtime validation for external data, and simple control flow over clever type tricks.

Workflow

  1. Identify the boundary. Library: optimize for stable public types, portability, and narrow exports. Application: optimize for operability, runtime validation, and maintainable module boundaries.
  2. Model data before behavior. Prefer discriminated unions, branded/domain types, and small interfaces over optional-field soup.
  3. Decide where trust begins. Treat network, env, file, CLI, and user input as unknown until validated.
  4. Keep types and implementation aligned. Prefer deriving types from values and functions over duplicating parallel definitions.
  5. Use async intentionally. Model failure and cancellation explicitly; avoid floating promises and hidden concurrency.
  6. Verify before finalizing. Run the project’s formatter, linter, type checker, and tests. Treat type errors as design feedback.

Load References By Need

Need Reference
Project shape, tsconfig, modules, exports, tooling references/workflow.md
Boundary validation, error handling, async and promises references/runtime-and-errors.md
API design, unions, narrowing, generics, utility types references/types-and-api-design.md
React/TSX state, props, hooks, and event typing references/react-and-tsx.md
Testing, mocks, fixtures, snapshots, review checklist references/testing-and-quality.md
Performance, allocation, iteration, and common footguns references/performance-and-footguns.md

Default Standards

  • Enable strict mode and keep it on.
  • Prefer unknown over any at trust boundaries.
  • Validate external data at runtime before treating it as domain data.
  • Prefer discriminated unions over boolean mode flags and optional-field matrices.
  • Keep exports intentional. Avoid giant barrel files that hide ownership and increase coupling.
  • Return typed domain values from core logic; isolate framework types at the edges.
  • Use Promise<void> and await intentionally. Do not leave floating promises.
  • Prefer stable, readable types over maximally clever conditional-type machinery.

Read the full file on GitHub · 67 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. 1mo ago First seen · 67 lines · 122 tokens per session scan A 0f8d0f26c3a9

Subscribe to this mod's changes

typescript-engineering is a skill published in the GitHub repository mfmezger/ai_agent_dotfiles (7 stars, last pushed 3mo ago), licensed MIT. It adds 122 tokens to every session and 874 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-08-31.

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