webctl 0.1.2

Browser automation via CLI — for humans and agents

webctl

Browser automation for AI agents and humans, built on the command line.

webctl start
webctl navigate "https://google.com"
webctl type 'role=combobox name~="Search"' "best restaurants nearby" --submit
webctl snapshot --interactive-only --limit 20
webctl stop --daemon

Why CLI Instead of MCP?

MCP browser tools have a fundamental problem: the server controls what enters your context. With Playwright MCP, every response includes the full accessibility tree plus console messages (default: "info" level). After a few page queries, your context is full.

CLI flips this around: you control what enters context.

# Filter before context
webctl snapshot --interactive-only --limit 30      # Only buttons, links, inputs
webctl snapshot --within "role=main"               # Skip nav, footer, ads

# Pipe through Unix tools
webctl snapshot | grep -i "submit"                 # Find specific elements
webctl --format jsonl snapshot | jq '.data.role'   # Extract with jq
webctl snapshot | head -50                         # Truncate output

Beyond filtering, CLI gives you:

Capability	CLI	MCP
Filter output	Built-in flags + grep/jq/head	Server decides
Debug	Run same command as agent	Opaque
Cache	webctl snapshot > cache.txt	Every call hits server
Script	Save to .sh, version control	Ephemeral
Timeout	timeout 30 webctl ...	Internal only
Parallelize	parallel, xargs, &	Server-dependent
Human takeover	Same commands	Different interface

Quick Start

pip install webctl      # Requires Python 3.11+
webctl setup            # Downloads Chromium (~150MB)

Verify it works:

webctl start
webctl navigate "https://example.com"
webctl snapshot --interactive-only
webctl stop --daemon

Install from source

git clone https://github.com/cosinusalpha/webctl
cd webctl
uv sync && uv run webctl setup

Linux system dependencies

playwright install-deps chromium
# Or manually: sudo apt-get install libnss3 libatk1.0-0 libatk-bridge2.0-0 ...

Core Concepts

Sessions

Browser stays open across commands. Cookies persist to disk.

webctl start                    # Visible browser
webctl start --mode unattended  # Headless
webctl -s work start            # Named profile (separate cookies)
webctl stop --daemon            # Shutdown everything

Element Queries

Semantic targeting based on ARIA roles - stable across CSS refactors:

role=button                     # Any button
role=button name="Submit"       # Exact match
role=button name~="Submit"      # Contains (preferred)
role=textbox name~="Email"      # Input field
role=link name~="Sign in"       # Link

Output Control

webctl snapshot                                    # Human-readable
webctl --quiet navigate "..."                      # Suppress events
webctl --result-only --format jsonl navigate "..." # Pure JSON, final result only

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Commands

Navigation

webctl navigate "https://..."   # Go to URL
webctl back                     # History back
webctl forward                  # History forward
webctl reload                   # Refresh

Observation

webctl snapshot                           # Full a11y tree
webctl snapshot --interactive-only        # Buttons, links, inputs only
webctl snapshot --limit 30                # Cap output
webctl snapshot --within "role=main"      # Scope to container
webctl snapshot --roles "button,link"     # Filter by role
webctl query "role=button name~=Submit"   # Debug query, get suggestions
webctl screenshot --path shot.png         # Screenshot

Interaction

webctl click 'role=button name~="Submit"'
webctl type 'role=textbox name~="Email"' "[e-mail]"
webctl type 'role=textbox name~="Search"' "query" --submit  # Type + Enter
webctl select 'role=combobox name~="Country"' --label "Germany"
webctl check 'role=checkbox name~="Remember"'
webctl press Enter
webctl scroll down
webctl upload 'role=button name~="Upload"' --file ./doc.pdf

Wait Conditions

webctl wait network-idle
webctl wait 'exists:role=button name~="Continue"'
webctl wait 'visible:role=dialog'
webctl wait 'hidden:role=progressbar'
webctl wait 'url-contains:"/dashboard"'

Session Management

webctl status                   # Current state (includes console error counts)
webctl save                     # Persist cookies now
webctl sessions                 # List profiles
webctl pages                    # List tabs
webctl focus p2                 # Switch tab
webctl close-page p1            # Close tab

Console Logs

webctl console                  # Get last 100 logs
webctl console --count          # Just counts by level (LLM-friendly)
webctl console --level error    # Filter to errors only
webctl console --follow         # Stream new logs continuously
webctl console -n 50 -l warn    # Last 50 warnings

Setup & Config

webctl setup                    # Install browser
webctl doctor                   # Diagnose installation
webctl init                     # Add to agent configs (CLAUDE.md, etc.)
webctl config show              # Show settings
webctl config set idle_timeout 1800

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Agent Integration

Tell your AI agent to use webctl. The easiest way:

webctl init                     # Creates CLAUDE.md, GEMINI.md, etc.
webctl init --agents claude     # Only specific agents

Or manually add to your agent's config:

For web browsing, use webctl CLI. Run `webctl agent-prompt` for instructions.

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For AI Agents

This section is designed to be read by AI agents directly.

webctl Quick Reference

Control a browser via CLI. Start with webctl start, end with webctl stop --daemon.

Commands:

webctl start                              # Open browser
webctl navigate "URL"                     # Go to URL
webctl snapshot --interactive-only        # See clickable elements
webctl click 'role=button name~="Text"'   # Click element
webctl type 'role=textbox name~="Field"' "text"           # Type
webctl type 'role=textbox name~="Field"' "text" --submit  # Type + Enter
webctl select 'role=combobox' --label "Option"            # Dropdown
webctl wait 'exists:role=button name~="..."'              # Wait for element
webctl stop --daemon                      # Close browser

Query syntax:

• role=button - By ARIA role (button, link, textbox, combobox, checkbox)
• name~="partial" - Partial match (preferred, more robust)
• name="exact" - Exact match

Example - Login:

webctl start
webctl navigate "https://site.com/login"
webctl type 'role=textbox name~="Email"' "[e-mail]"
webctl type 'role=textbox name~="Password"' "secret" --submit
webctl wait 'url-contains:"/dashboard"'

Tips:

• Use --interactive-only to reduce output (only buttons, links, inputs)
• Use name~= for partial matching (handles minor text changes)
• Use webctl query "..." if element not found - shows suggestions
• Use --quiet to suppress event output
• Sessions persist cookies - login once, stay logged in
• Check webctl status for console error counts before investigating
• Use webctl console --count for log summary, --level error for details

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Architecture

┌─────────────┐     TCP/IPC      ┌─────────────┐
│   CLI       │ ◄──────────────► │   Daemon    │
│  (webctl)   │    JSON-RPC      │  (browser)  │
└─────────────┘                  └─────────────┘
      │                                 │
      ▼                                 ▼
  Agent/User                      Chromium + Playwright

• CLI: Stateless, sends commands to daemon
• Daemon: Manages browser, auto-starts on first command
• Profiles: ~/.local/share/webctl/profiles/
• Config: ~/.config/webctl/config.json

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License

MIT