What is agent-browser?

A browser automation skill for navigating websites, filling forms, clicking controls, taking screenshots, extracting data, and testing web apps.

Use it to open pages, inspect interactive elements, complete forms, interact with controls, wait for page changes, and capture or extract web content.

It removes repetitive manual browser steps and supports checking how websites behave through Chrome or Chromium.

agent-browser — Skill for Claude Code and Codex by halfmoon-labs

Install

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.

Any agent

npx skills add halfmoon-labs/halfmoon --skill agent-browser

Clone the repo

git clone --depth 1 https://github.com/halfmoon-labs/halfmoon

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/halfmoon-labs/halfmoon/agent-browser/github.svg)](https://agentmods.dev/skills/halfmoon-labs/halfmoon/agent-browser)

Your own site

<a href="https://agentmods.dev/skills/halfmoon-labs/halfmoon/agent-browser"><img src="https://agentmods.dev/badge/skills/halfmoon-labs/halfmoon/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/halfmoon-labs/halfmoon/agent-browser"><img src="https://agentmods.dev/badge/skills/halfmoon-labs/halfmoon/agent-browser.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,000 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod in the catalogue.

Token cost

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	$0.00036	$0.01000
Opus 5.5	$0.00014	$0.00400
Sonnet 5.5	$0.00007	$0.00200
Haiku 4.5	$0.00004	$0.00100

Measured 2mo ago against content hash 70b6529d5407, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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 2mo 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.

Origin

This is a copy

100% identical to agent-browser — 0 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.

workspace/skills/agent-browser/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Browser

CLI browser automation via Chrome/Chromium CDP. Install: npm i -g agent-browser && agent-browser install.

Before using this skill, verify the tool is available by running which agent-browser. If the command is not found, tell the user that browser automation requires the agent-browser CLI and Chromium, which are only available in the heavy container image. Do not attempt to install it at runtime.

Core Workflow

agent-browser open <url> — navigate
agent-browser snapshot -i — get interactive elements with refs (@e1, @e2, ...)
Interact using refs — click @e1, fill @e2 "text"
Re-snapshot after any navigation or DOM change — refs are invalidated

agent-browser open https://example.com/form
agent-browser snapshot -i
# @e1 [input] "Email", @e2 [input] "Password", @e3 [button] "Submit"
agent-browser fill @e1 "[email protected]"
agent-browser fill @e2 "secret"
agent-browser click @e3
agent-browser wait --load networkidle
agent-browser snapshot -i

Chain commands with && when you don't need intermediate output:

agent-browser open https://example.com && agent-browser wait --load networkidle && agent-browser snapshot -i

Commands

# Navigation
agent-browser open <url>
agent-browser close

# Snapshot
agent-browser snapshot -i                # Interactive elements with refs
agent-browser snapshot -s "#selector"    # Scope to CSS selector

# Interaction (use @refs from snapshot)
agent-browser click @e1
agent-browser fill @e2 "text"            # Clear + type
agent-browser type @e2 "text"            # Type without clearing
agent-browser select @e1 "option"
agent-browser check @e1
agent-browser press Enter
agent-browser scroll down 500

# Get info
agent-browser get text @e1
agent-browser get url
agent-browser get title

# Wait
agent-browser wait @e1                   # Wait for element
agent-browser wait --load networkidle    # Wait for network idle
agent-browser wait --url "**/dashboard"  # Wait for URL pattern
agent-browser wait --text "Welcome"      # Wait for text
agent-browser wait 2000                  # Wait ms

# Capture
agent-browser screenshot                 # Screenshot to temp dir
agent-browser screenshot --full          # Full page
agent-browser screenshot --annotate      # With numbered element labels ([N] -> @eN)
agent-browser pdf output.pdf

# Semantic locators (when refs unavailable)
agent-browser find text "Sign In" click
agent-browser find label "Email" fill "[email protected]"
agent-browser find role button click --name "Submit"

Read the full file on GitHub · 130 lines

Changes

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.

2mo ago First seen · 130 lines · 36 tokens per session scan A 70b6529d5407

Subscribe to this mod's changes

agent-browser is a skill published in the GitHub repository halfmoon-labs/halfmoon (11 stars, last pushed 6mo ago), licensed MIT. It adds 36 tokens to every session and 1,000 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to agent-browser, differing in 0 lines, and is treated as a copy.

Browser automation

agent-browser next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
agent-browserhalfmoon-labs/halfmoon	Skill	11	6mo ago	MIT	A	36	Claude Code, Codex
interactive-loginyc-software/qm	Skill	16k	today	MIT	A	46	Claude Code, Codex
pinchtab-mcppinchtab/pinchtab	Skill	11k	10d ago	MIT	A	52	Claude Code, Codex
azure-messaging-webpubsub-javamicrosoft/skills	Skill	3.2k	today	MIT	A	43	Claude Code
cua-driverdavidondrej/skills	Skill	4.3k	today	MIT	A	68	Claude Code, Codex
open-design-browsercompozy/compozy	Skill	2.9k	today	MIT	A	56	Claude Code, Codex
southwestborski/travel-hacking-toolkit	Skill	895	yesterday	MIT	A	40	Claude Code