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 agentmods add skills/marcusrbrown/systematic/agent-browsernpx skills add marcusrbrown/systematic --skill agent-browsergit clone --depth 1 https://github.com/marcusrbrown/systematicWhat 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 | $0.00200 | $0.00691 |
| Opus 5 | $0.00100 | $0.00345 |
| Sonnet 5 | $0.00040 | $0.00138 |
| Haiku 4.5 | $0.00020 | $0.00069 |
Grade A, and why
agent-browser 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.
This is a copy
98% identical to agent-browser — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
agent-browser
Fast browser automation CLI for AI agents. Chrome/Chromium via CDP with accessibility-tree snapshots and compact @eN element refs.
Install: npm i -g agent-browser && agent-browser install
Start here
This file is a discovery stub, not the usage guide. Before running any agent-browser command, load the actual workflow content from the CLI:
agent-browser skills get core # start here — workflows, common patterns, troubleshooting
agent-browser skills get core --full # include full command reference and templates
The CLI serves skill content that always matches the installed version, so instructions never go stale. The content in this stub cannot change between releases, which is why it just points at skills get core.
Specialized skills
Load a specialized skill when the task falls outside browser web pages:
agent-browser skills get electron # Electron desktop apps (VS Code, Slack, Discord, Figma, ...)
agent-browser skills get slack # Slack workspace automation
agent-browser skills get dogfood # Exploratory testing / QA / bug hunts
agent-browser skills get derive-client # Record a HAR, derive a standalone API client for a site
agent-browser skills get vercel-sandbox # agent-browser inside Vercel Sandbox microVMs
agent-browser skills get agentcore # AWS Bedrock AgentCore cloud browsers
Run agent-browser skills list to see everything available on the installed version.
Why agent-browser
- Fast native Rust CLI, not a Node.js wrapper
- Works with any AI agent (Cursor, Claude Code, Codex, Continue, Windsurf, etc.)
- Chrome/Chromium via CDP with no Playwright or Puppeteer dependency
- Accessibility-tree snapshots with element refs for reliable interaction
- Sessions, authentication vault, state persistence, video recording
- Specialized skills for Electron apps, Slack, exploratory testing, cloud providers
Observability Dashboard
The dashboard runs independently of browser sessions on port 4848 and can also be opened through a proxied or forwarded URL such as https://dashboard.agent-browser.localhost. Agents should stay on the dashboard origin: session tabs, status, and stream traffic are proxied internally, so session ports do not need to be exposed.
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.
- 2d ago First seen · 51 lines · 200 tokens per session scan A f9b5e8b490ae
agent-browser is a skill published in the GitHub repository marcusrbrown/systematic (24 stars, last pushed 3d ago), licensed MIT. It adds 200 tokens to every session and 691 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to agent-browser, differing in 1 line, and is treated as a copy.
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Criteria for reviewing implementation plans against quality standards.
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