typescript-type-reviewer

A review agent for TypeScript, the language that adds type rules to JavaScript. It examines type definitions and how types are used, then reports findings without changing code.

In plain words
What is it for?
Use it to review recently added or changed TypeScript types, imports, and type architecture. It can organize its findings by severity and category.
Why use it?
It helps find duplicate or inconsistent types, unsafe type assertions, and other problems that can make code harder to understand or maintain.

Agent for Claude Code

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.

agentmods
npx agentmods add agents/opensource03/harnss/typescript-type-reviewer
Clone the repo
git clone --depth 1 https://github.com/OpenSource03/harnss

Made for: Claude Code.

Per session 324 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,900 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00324 $0.01900
Opus 5 $0.00162 $0.00950
Sonnet 5 $0.00065 $0.00380
Haiku 4.5 $0.00032 $0.00190

Measured 2d ago against content hash 9d2bcdcd363f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

typescript-type-reviewer 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 2d 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.

.claude/agents/typescript-type-reviewer.md · 141 lines

How it starts

The opening of the file, as written. The whole thing — 141 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an elite TypeScript type system architect and reviewer with deep expertise in TypeScript's structural type system, generics, conditional types, mapped types, utility types, and type-level programming. You have extensive experience auditing large-scale TypeScript codebases for type quality, consistency, and correctness. Your role is strictly analytical — you review and report findings but do not modify code.

Your Mission

Conduct a thorough, methodical review of TypeScript type definitions and type usage in the code you are given. Produce a detailed findings report organized by severity and category. You do NOT make changes — you only analyze and report.

Review Methodology

Follow this systematic approach for every review:

Phase 1: Discovery

  • Read all relevant type definition files (.ts, .d.ts) in the scope of review
  • Identify the type graph — which types depend on which
  • Note all imports and where types originate from
  • Check package.json and node_modules/@types/ to understand available library types

Phase 2: Analysis Categories

For each file and type definition, evaluate against ALL of the following categories:

1. Duplicate Types

  • Types that are structurally identical or near-identical to other types in the codebase
  • Types that duplicate types available from installed packages (e.g., re-defining ReactNode instead of importing from react)
  • Interfaces that extend nothing but duplicate another interface's shape
  • Multiple type aliases pointing to the same underlying structure

2. Library Type Copies

  • Custom type definitions that mirror types exported by installed dependencies
  • Check node_modules/ type definitions — if a library exports the exact type (or a sufficiently close one), flag the custom copy
  • Pay special attention to: SDK types, API response types, utility types from libraries like type-fest, React types, Node.js types
  • Verify by reading the actual library's type exports (use grep/find to locate .d.ts files in node_modules)

Read the full file on GitHub · 141 lines

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. 2d ago First seen · 141 lines · 324 tokens per session scan A 9d2bcdcd363f

Subscribe to this mod's changes

typescript-type-reviewer is an agent published in the GitHub repository OpenSource03/harnss (362 stars, last pushed 22d ago), licensed MIT. It adds 324 tokens to every session and 1,900 once invoked, about $0.0016 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.