agent-browser is a command-line tool that lets AI agents control web browsers for tasks such as clicking, navigation, and screenshots. Developers use it to automate browser interactions from agent workflows.
Borrowing it
Nothing to install: this file belongs to vercel-labs/agent-browser. 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-labs/agent-browser/main/AGENTS.mdgit clone --depth 1 https://github.com/vercel-labs/agent-browserWrote 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-labs/agent-browser/agents-md)<a href="https://agentmods.dev/instructions/vercel-labs/agent-browser/agents-md"><img src="https://agentmods.dev/badge/instructions/vercel-labs/agent-browser/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-labs/agent-browser/agents-md"><img src="https://agentmods.dev/badge/instructions/vercel-labs/agent-browser/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 | $0.02310 | $0.02310 |
| Opus 5.5 | $0.00924 | $0.00924 |
| Sonnet 5.5 | $0.00462 | $0.00462 |
| Haiku 4.5 | $0.00231 | $0.00231 |
Grade A, and why
agent-browser 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 21d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- antigravity-browser-bridge AGENTS.md — 100% identical, 80 lines differ
How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Instructions for AI coding agents working with this codebase.
Package Manager
This project uses pnpm. Always use pnpm instead of npm or yarn for installing dependencies, running scripts, etc. (e.g., pnpm install, pnpm run build).
Code Style
- Do not use emojis in code, output, or documentation. Unicode symbols (✓, ✗, →, ⚠) are acceptable.
- In documentation and markdown, never use double hyphens (
--) as a dash. Use an emdash (—) sparingly when needed. Prefer rewriting the sentence to avoid dashes entirely. - CLI colored output uses
cli/src/color.rs. This module respects theNO_COLORenvironment variable. Never use hardcoded ANSI color codes. - CLI flags must always use kebab-case (e.g.,
--auto-connect,--allow-file-access). Never use camelCase for flags (e.g.,--autoConnectis wrong).
Documentation
Do not hard-wrap prose in documentation files such as Markdown, MDX, and READMEs; let the editor or renderer wrap text naturally.
When adding or changing user-facing features (new flags, commands, behaviors, environment variables, etc.), update all of the following:
cli/src/output.rs—--helpoutput (flags list, examples, environment variables)README.md— Options table, relevant feature sections, examplesskill-data/core/SKILL.md(and itsreferences/) — so AI agents know about the feature when they load the core skill. Editskill-data/core/SKILL.mdfor overview/workflow changes; editskill-data/core/references/*.mdfor detailed reference content. Do not put feature content inskills/agent-browser/SKILL.md— that file is an intentionally thin discovery stub fornpx skills addand exists only to redirect agents toagent-browser skills get core.docs/content/docs/— the Geistdocs site (MDX pages); routing and API handlers live indocs/src/app/- Inline doc comments in the relevant source files
This applies to changes that either human users or AI agents would need to know about. Do not skip any of these locations.
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.
- 21d ago Changed · +16 lines · +429 tokens per session 8da81b2b0c75
- 1mo ago Changed · -62 lines · -378 tokens per session bdb22446ee54
- 1mo ago First seen · 215 lines · 2,259 tokens per session scan A ddc141989d48
agent-browser AGENTS.md is an instructions file published in the GitHub repository vercel-labs/agent-browser (44,717 stars, last pushed today), licensed Apache-2.0. It adds 2,310 tokens to every session, about $0.0092 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 2026-08-30.
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).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.