Web Browser Tool

You have the ability to browse the web with a full browser via the system shell.

Always use the built-in bash CLI tool web to interact with and test web apps as you build features. This should be your GO-TO TOOL for verifying functionality, build status, etc.

Basic Usage

web <url> [options]

By default the page is converted to markdown and displayed to stdout:

web example.com
web localhost:4000/dashboard

You can redirect output to a file:

web example.com --raw > output.html
web example.com --raw > output.json

Never pass --raw or --truncate-after unless the user asks, or if it makes sense (e.g., fetching JSON from an API).

Options

Option	Description
--raw	Output raw HTML/JSON instead of markdown
--truncate-after <n>	Truncate after n characters (default: 100000)
--screenshot <path>	Save screenshot to filepath
--profile <name>	Use named session profile (default: "default")
--js <code>	Execute JavaScript after page loads
--form <id>	Target form by ID for submission
--input <name>	Field name to fill (repeatable)
--value <value>	Value for preceding --input
--after-submit <url>	URL to load after form submission

Session Persistence

Each invocation of web uses a shared session — cookie sessions and other state are preserved across separate invocations. This means you can log in to a site and then issue another web command to view or interact with a logged-in page.

Use the optional --profile argument to browse under unique profiles, which is useful for testing multiple logins or sessions:

web http://localhost:4000 --profile "user1"
web http://localhost:4000 --profile "user2"

Common Patterns

Verify a Page Works

web localhost:4000/users

Authenticated Session

# 1. Login and establish session
web localhost:4000/login \
  --form login_form \
  --input email --value user@example.com \
  --input password --value secret \
  --profile app_session

# 2. Access protected pages with same session
web localhost:4000/dashboard --profile app_session

Screenshot for Visual Verification

web localhost:4000/dashboard --screenshot /tmp/dashboard.png

Fetch JSON from an API

web localhost:4000/api/health --raw

Execute JavaScript After Load

web localhost:4000 --js "document.querySelector('button').click()"

LiveView Form Submission

web localhost:4000/users/new \
  --form user_form \
  --input "user[name]" --value "John Doe" \
  --input "user[email]" --value "john@example.com"

Navigate After Form Submit

web localhost:4000/login \
  --form login_form \
  --input email --value admin@test.com \
  --input password --value password123 \
  --after-submit localhost:4000/admin/dashboard

Key Capabilities

• JavaScript rendering: Unlike simple HTTP fetches, web renders JavaScript — essential for SPAs, Phoenix LiveView, React/Vue/Angular apps
• Phoenix LiveView support: Automatically handles .phx-connected state waiting, form submissions with loading states
• Session persistence: Cookies and state preserved across invocations via shared or named profiles

When to Use web vs Other Tools

Scenario	Tool
Simple static page (no JS)	WebFetch
JavaScript-rendered content	web
Form submission needed	web
Screenshot required	web
Session persistence needed	web
Phoenix LiveView app	web
Verifying feature during dev	web