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 aegntic/compound-engineering --skill agent-browsergit clone --depth 1 https://github.com/aegntic/compound-engineeringWrote 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/aegntic/compound-engineering/agent-browser)<a href="https://agentmods.dev/skills/aegntic/compound-engineering/agent-browser"><img src="https://agentmods.dev/badge/skills/aegntic/compound-engineering/agent-browser/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/aegntic/compound-engineering/agent-browser"><img src="https://agentmods.dev/badge/skills/aegntic/compound-engineering/agent-browser.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 | $0.00077 | $0.01556 |
| Opus 5.5 | $0.00031 | $0.00622 |
| Sonnet 5.5 | $0.00015 | $0.00311 |
| Haiku 4.5 | $0.00008 | $0.00156 |
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 1mo 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
95% identical to agent-browser — 12 lines 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 — 234 lines — stays where its author put it; the contents beside it link to each section on GitHub.
agent-browser: CLI Browser Automation
Vercel's headless browser automation CLI designed for AI agents. Uses ref-based selection (@e1, @e2) from accessibility snapshots.
Setup Check
# Check installation
command -v agent-browser >/dev/null 2>&1 && echo "Installed" || echo "NOT INSTALLED - run: npm install -g agent-browser && agent-browser install"
Install if needed
npm install -g agent-browser
agent-browser install # Downloads Chromium
Core Workflow
The snapshot + ref pattern is optimal for LLMs:
- Navigate to URL
- Snapshot to get interactive elements with refs
- Interact using refs (@e1, @e2, etc.)
- Re-snapshot after navigation or DOM changes
# Step 1: Open URL
agent-browser open https://example.com
# Step 2: Get interactive elements with refs
agent-browser snapshot -i --json
# Step 3: Interact using refs
agent-browser click @e1
agent-browser fill @e2 "search query"
# Step 4: Re-snapshot after changes
agent-browser snapshot -i
Key Commands
Navigation
agent-browser open <url> # Navigate to URL
agent-browser back # Go back
agent-browser forward # Go forward
agent-browser reload # Reload page
agent-browser close # Close browser
Snapshots (Essential for AI)
agent-browser snapshot # Full accessibility tree
agent-browser snapshot -i # Interactive elements only (recommended)
agent-browser snapshot -i --json # JSON output for parsing
agent-browser snapshot -c # Compact (remove empty elements)
agent-browser snapshot -d 3 # Limit depth
Interactions
agent-browser click @e1 # Click element
agent-browser dblclick @e1 # Double-click
agent-browser fill @e1 "text" # Clear and fill input
agent-browser type @e1 "text" # Type without clearing
agent-browser press Enter # Press key
agent-browser hover @e1 # Hover element
agent-browser check @e1 # Check checkbox
agent-browser uncheck @e1 # Uncheck checkbox
agent-browser select @e1 "option" # Select dropdown option
agent-browser scroll down 500 # Scroll (up/down/left/right)
agent-browser scrollintoview @e1 # Scroll element into view
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.
- 1mo ago First seen · 234 lines · 77 tokens per session scan A bb84ff1ef787
agent-browser is a skill published in the GitHub repository aegntic/compound-engineering (2 stars, last pushed 4mo ago), licensed MIT. It adds 77 tokens to every session and 1,556 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 95% identical to agent-browser, differing in 12 lines, and is treated as a copy.
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