vercel/next-evals-oss is a set of evaluations that tests how well AI coding agents complete tasks in Next.js applications. Each evaluation gives an agent a small app in an isolated sandbox and checks the resulting code with assertions that are hidden from the agent. The catalogue entries provide instructions and a skill for running or developing these evaluations.
Borrowing it
Nothing to install: this file belongs to vercel/next-evals-oss. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/vercel/next-evals-oss/main/AGENTS.mdgit clone --depth 1 https://github.com/vercel/next-evals-ossWrote 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/instructions/vercel/next-evals-oss/agents-md)<a href="https://agentmods.dev/instructions/vercel/next-evals-oss/agents-md"><img src="https://agentmods.dev/badge/instructions/vercel/next-evals-oss/agents-md/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/instructions/vercel/next-evals-oss/agents-md"><img src="https://agentmods.dev/badge/instructions/vercel/next-evals-oss/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00416 | $0.00416 |
| Opus 5.5 | $0.00166 | $0.00166 |
| Sonnet 5.5 | $0.00083 | $0.00083 |
| Haiku 4.5 | $0.00042 | $0.00042 |
Grade A, and why
next-evals-oss AGENTS.md 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 13d 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.
What it actually says
Working in this repo
Read README.md first — it is the spec for this repo, not a summary of it. "Adding a new model", "Reasoning effort", "Model retention policy", and "Scoring and cost methodology" are the rules the board is published under.
Skills
Skills live in .agents/skills/, with .claude/skills symlinked to
that directory so Claude Code and other harnesses read the same copy.
| Skill | Use it for |
|---|---|
add-eval-model |
Adding, registering, running, tiering, or publishing a model on nextjs.org/evals |
Finish the run
Almost every task here ends in numbers on a public board, and the work only counts once those numbers exist. An experiment with no results is not exported at all, so a PR that registers a model and stops changes nothing anyone can see — the README calls that state "a staging post, not a destination".
Merging to main here is what publishes: nextjs.org/evals fetches
agent-results.json from this repo's main on the server, and main CI invalidates
its cache. vercel/front used to carry a copy of the file and no longer does
(vercel/front#85415, 2026-09-09), so a results PR against the site repo is not part of
the task — only a site-side change that is genuinely about the site is. See
"Publishing to nextjs.org/evals" in the README.
Eval runs cost real money and take 30–90 minutes. That is the normal price of a task in this repo, not a reason to stop and ask. Run them, then report what they cost.
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.
- 13d ago Changed · +3 tokens per session 0223febd2e0b
- 1mo ago Changed · +5 lines · +72 tokens per session 095aa746acd0
- 1mo ago First seen · 29 lines · 341 tokens per session scan A 5ad22c902dc6
next-evals-oss AGENTS.md is an instructions file published in the GitHub repository vercel/next-evals-oss (327 stars, last pushed today), licensed MIT. It adds 416 tokens to every session, about $0.0017 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 2026-09-10.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.