Next.js is a React framework for building applications that run across the browser and Node.js, including server-rendered applications. It is used by developers building web applications with React components.
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 skills add vercel/next.js --skill next-dev-loopgit clone --depth 1 https://github.com/vercel/next.jsWrote 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.
[](https://agentmods.dev/skills/vercel/next.js/next-dev-loop)<a href="https://agentmods.dev/skills/vercel/next.js/next-dev-loop"><img src="https://agentmods.dev/badge/skills/vercel/next.js/next-dev-loop/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.
<a href="https://agentmods.dev/skills/vercel/next.js/next-dev-loop"><img src="https://agentmods.dev/badge/skills/vercel/next.js/next-dev-loop.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Snyk pass
- NVIDIA SkillSpector warn
- Socket pass
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium MCP Rug Pull · line 43 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00068 | $0.02198 |
| Opus 5.5 | $0.00027 | $0.00879 |
| Sonnet 5.5 | $0.00014 | $0.00440 |
| Haiku 4.5 | $0.00007 | $0.00220 |
Grade A, and why
next-dev-loop scanned grade A 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 17d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
those same flags. Don't fall back to `curl`; it bypasses the browser Copies of this mod
3 near-identical copies found in the catalogue:
- next-dev-loop — 94% identical, 47 lines differ
- next-dev-loop — 92% identical, 36 lines differ
- next-dev-loop — 91% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 208 lines — stays where its author put it; the contents beside it link to each section on GitHub.
next-dev-loop
The edit/verify rhythm during next dev — make a change, then
confirm it actually works at runtime, not only that the types or
the build are happy.
You verify through two views of the same running app:
/_next/mcp— an HTTP endpoint Next.js exposes about itself. Knows framework-specific things: routes, segments, RSC, server actions, server logs, and errors as Next.js saw them. Calltools/listfor the current surface.agent-browser— a CLI that drives a real Chrome. Knows framework-agnostic browser things: DOM, console, network, React fiber, vitals. Before driving it, runagent-browser skills get coreonce for the version-matched usage guide — don't guess subcommands from memory.
The two views cross-check each other.
requires
- Next.js 16.3+ with Turbopack —
/_next/mcpplus the proactive compile check viaget_compilation_issues. agent-browser>= 0.31.1 — React introspection, worktree-scopedsession id, idempotent--restore, and launch flag reconciliation.
These are hard floors, not soft preferences. If anything is missing, tell the user how to upgrade and stop. Don't fall back to grepping source or to a weaker probe — this skill assumes both views are live at the versions above.
- Upgrade Next.js:
pnpm next upgrade(ornpx next upgrade). Docs: https://nextjs.org/docs/app/getting-started/upgrading (version-16 guide: https://nextjs.org/docs/app/guides/upgrading/version-16) - Install or upgrade
agent-browser:npm i -g agent-browser@latest. If the CLI isn't onPATH, install it before continuing — preflight expects to invoke it directly.
preflight
Once per session, confirm both views are live.
-
Open
agent-browserat the target URL, restoring saved login state when present. First derive one stable session id for this checkout and use it for everyagent-browsercommand:SESSION="$(agent-browser session id --scope worktree --prefix next-dev-loop)" export AGENT_BROWSER_SESSION="$SESSION" export AGENT_BROWSER_RESTORE="$SESSION"
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.
- 17d ago Changed · +6 lines ca45c937ae77
- 24d ago Changed ff2ba55895cd
- 27d ago Changed · +14 lines e3221747c12a
- 1mo ago Changed · +4 lines dc0d71d7b605
- 1mo ago First seen · 184 lines · 68 tokens per session scan A 6b8749833d92
next-dev-loop is a skill published in the GitHub repository vercel/next.js (143,028 stars, last pushed today), licensed MIT. It adds 68 tokens to every session and 2,198 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
verify
Build/launch/drive recipe for verifying apps/docs changes at runtime (demos, docs pages, llms.txt).
playwright-test
Write a playwright test, make sure it runs, and is not flaky.
quality-engineering-playwright-pom-generation
Generates Playwright page objects from an executable test plan, one class per screen with ladder-compliant locators and no assertions, wired into a shared fixture. Use when a web scenario needs a page object that does not exist yet, or when locators drift and the page object must be rebuilt.
playwright-page-objects
Use when creating page objects or refactoring Playwright E2E tests for better maintainability with Page Object Model patterns.
playtest
Drive a real browser against a game with vg playtest: smoke checks, scripted playtests, vg playtest run (a model plays the game and reports), softlock detection, screenshots and visual diffs, on localhost or a deployed URL.
webapp-testing
Web application testing principles. E2E, Playwright, deep audit strategies.