expert-nextjs-developer

A specialised coding agent for Next.js 16 and modern React applications written in TypeScript. Next.js is a framework for building web applications, while its App Router organises pages and server-side features.

In plain words
What is it for?
Developing Next.js applications with the App Router, Server Components, Cache Components, Turbopack, and TypeScript.
Why use it?
It provides focused help for projects using these specific web-development tools and patterns.

Agent

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/bhf/st-k8s/expert-nextjs-developer
Clone the repo
git clone --depth 1 https://github.com/bhf/st-k8s
Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,341 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
Origin unknown 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 $0.00029 $0.04341
Opus 5 $0.00015 $0.02171
Sonnet 5 $0.00006 $0.00868
Haiku 4.5 $0.00003 $0.00434

Measured 2d ago against content hash d0c42a0cc783, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

expert-nextjs-developer scanned grade B with 1 finding 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

const res = await fetch("https://api.example.com/posts", { method: "POST",
.github/agents/expert-nextjs-developer.agent.md · 477 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 477 lines · 29 tokens per session scan B d0c42a0cc783

Subscribe to this mod's changes

expert-nextjs-developer is an agent published in the GitHub repository bhf/st-k8s (1 stars, last pushed 3mo ago), with no licence file. It adds 29 tokens to every session and 4,341 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 1 finding (sends data to an external url). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.