OpenCLI Browser — Browser Automation for AI Agents

Control Chrome step-by-step via CLI. Reuses existing login sessions — no passwords needed.

Prerequisites

bash

opencli doctor    # Verify extension + daemon connectivity

Requires: Chrome running + OpenCLI Browser Bridge extension installed.

Critical Rules

ALWAYS use
state
to inspect the page, NEVER use
screenshot
—
```
state
```
returns structured DOM with
```
[N]
```
element indices, is instant and costs zero tokens.
```
screenshot
```
requires vision processing and is slow. Only use
```
screenshot
```
when the user explicitly asks to save a visual.
ALWAYS use
click
/
type
/
select
for interaction, NEVER use
eval
to click or type —
```
eval "el.click()"
```
bypasses scrollIntoView and CDP click pipeline, causing failures on off-screen elements. Use
```
state
```
to find the
```
[N]
```
index, then
```
click <N>
```
.
Verify inputs with
get value
, not screenshots — after
```
type
```
, run
```
get value <index>
```
to confirm.
Run
state
after every page change — after
```
open
```
,
```
click
```
(on links),
```
scroll
```
, always run
```
state
```
to see the new elements and their indices. Never guess indices.
Chain commands aggressively with
&&
— combine
```
open + state
```
, multiple
```
type
```
calls, and
```
type + get value
```
into single
```
&&
```
chains. Each tool call has overhead; chaining cuts it.
eval
is read-only — use
```
eval
```
ONLY for data extraction (
```
JSON.stringify(...)
```
), never for clicking, typing, or navigating. Always wrap in IIFE to avoid variable conflicts:
```
eval "(function(){ const x = ...; return JSON.stringify(x); })()"
```
.
Minimize total tool calls — plan your sequence before acting. A good task completion uses 3-5 tool calls, not 15-20. Combine
```
open + state
```
as one call. Combine
```
type + type + click
```
as one call. Only run
```
state
```
separately when you need to discover new indices.
Prefer
network
to discover APIs — most sites have JSON APIs. API-based adapters are more reliable than DOM scraping.

Command Cost Guide

Cost	Commands	When to use
Free & instant	`state` , `get *` , `eval` , `network` , `scroll` , `keys`	Default — use these
Free but changes page	`open` , `click` , `type` , `select` , `back`	Interaction — run `state` after
Expensive (vision tokens)	`screenshot`	ONLY when user needs a saved image

Action Chaining Rules

Commands can be chained with

&&

. The browser persists via daemon, so chaining is safe.

Always chain when possible — fewer tool calls = faster completion:

bash

# GOOD: open + inspect in one call (saves 1 round trip)
opencli browser open https://example.com && opencli browser state

# GOOD: fill form in one call (saves 2 round trips)
opencli browser type 3 "hello" && opencli browser type 4 "world" && opencli browser click 7

# GOOD: type + verify in one call
opencli browser type 5 "test@example.com" && opencli browser get value 5

# GOOD: click + wait + state in one call (for page-changing clicks)
opencli browser click 12 && opencli browser wait time 1 && opencli browser state

# BAD: separate calls for each action (wasteful)
opencli browser type 3 "hello"    # Don't do this
opencli browser type 4 "world"    # when you can chain
opencli browser click 7            # all three together

Page-changing — always put last in a chain (subsequent commands see stale indices):

open <url>

back

click <link/button that navigates>

Rule: Chain when you already know the indices. Run

state

separately when you need to discover indices first.

Core Workflow

Navigate:
```
opencli browser open <url>
```
Inspect:
```
opencli browser state
```
→ elements with
```
[N]
```
indices
Interact: use indices —
```
click
```
,
```
type
```
,
```
select
```
,
```
keys
```

Wait (if needed):

opencli browser wait selector ".loaded"

wait text "Success"

Verify:

opencli browser state

opencli browser get value <N>

Repeat: browser stays open between commands
Save: write a TS adapter to
```
~/.opencli/clis/<site>/<command>.ts
```

Commands

Navigation

bash

opencli browser open <url>              # Open URL (page-changing)
opencli browser back                    # Go back (page-changing)
opencli browser scroll down             # Scroll (up/down, --amount N)
opencli browser scroll up --amount 1000

Inspect (free & instant)

bash

opencli browser state                   # Structured DOM with [N] indices — PRIMARY tool
opencli browser screenshot [path.png]   # Save visual to file — ONLY for user deliverables

Get (free & instant)

bash

opencli browser get title               # Page title
opencli browser get url                 # Current URL
opencli browser get text <index>        # Element text content
opencli browser get value <index>       # Input/textarea value (use to verify after type)
opencli browser get html                # Full page HTML
opencli browser get html --selector "h1" # Scoped HTML
opencli browser get attributes <index>  # Element attributes

Interact

bash

opencli browser click <index>           # Click element [N]
opencli browser type <index> "text"     # Type into element [N]
opencli browser select <index> "option" # Select dropdown
opencli browser keys "Enter"            # Press key (Enter, Escape, Tab, Control+a)

Wait

Three variants — use the right one for the situation:

bash

opencli browser wait time 3                       # Wait N seconds (fixed delay)
opencli browser wait selector ".loaded"            # Wait until element appears in DOM
opencli browser wait selector ".spinner" --timeout 5000  # With timeout (default 30s)
opencli browser wait text "Success"                # Wait until text appears on page

When to wait: After

open

on SPAs, after

click

that triggers async loading, before

eval

on dynamically rendered content.

Extract (free & instant, read-only)

Use

eval

ONLY for reading data. Never use it to click, type, or navigate.

bash

opencli browser eval "document.title"
opencli browser eval "JSON.stringify([...document.querySelectorAll('h2')].map(e => e.textContent))"

# IMPORTANT: wrap complex logic in IIFE to avoid "already declared" errors
opencli browser eval "(function(){ const items = [...document.querySelectorAll('.item')]; return JSON.stringify(items.map(e => e.textContent)); })()"

Selector safety: Always use fallback selectors —

querySelector

returns

null

on miss:

bash

# BAD: crashes if selector misses
opencli browser eval "document.querySelector('.title').textContent"

# GOOD: fallback with || or ?.
opencli browser eval "(document.querySelector('.title') || document.querySelector('h1') || {textContent:''}).textContent"
opencli browser eval "document.querySelector('.title')?.textContent ?? 'not found'"

Network (API Discovery)

bash

opencli browser network                  # Show captured API requests (auto-captured since open)
opencli browser network --detail 3       # Show full response body of request #3
opencli browser network --all            # Include static resources

Sedimentation (Save as CLI)

bash

opencli browser init hn/top              # Generate adapter scaffold at ~/.opencli/clis/hn/top.ts
opencli browser verify hn/top            # Test the adapter (adds --limit 3 only if `limit` arg is defined)

```
init
```
auto-detects the domain from the active browser session (no need to specify it)
```
init
```
creates the file + populates
```
site
```
,
```
name
```
,
```
domain
```
, and
```
columns
```
from current page
```
verify
```
runs the adapter end-to-end and prints output; if no
```
limit
```
arg exists in the adapter, it won't pass
```
--limit 3
```

Session

bash

opencli browser close                   # Close automation window

Example: Extract HN Stories

bash

opencli browser open https://news.ycombinator.com
opencli browser state                   # See [1] a "Story 1", [2] a "Story 2"...
opencli browser eval "JSON.stringify([...document.querySelectorAll('.titleline a')].slice(0,5).map(a => ({title: a.textContent, url: a.href})))"
opencli browser close

Example: Fill a Form

bash

opencli browser open https://httpbin.org/forms/post
opencli browser state                   # See [3] input "Customer Name", [4] input "Telephone"
opencli browser type 3 "OpenCLI" && opencli browser type 4 "555-0100"
opencli browser get value 3             # Verify: "OpenCLI"
opencli browser close

Saving as Reusable CLI — Complete Workflow

Step-by-step sedimentation flow:

bash

# 1. Explore the website
opencli browser open https://news.ycombinator.com
opencli browser state                          # Understand DOM structure

# 2. Discover APIs (crucial for high-quality adapters)
opencli browser eval "fetch('/api/...').then(r=>r.json())"   # Trigger API calls
opencli browser network                        # See captured API requests
opencli browser network --detail 0             # Inspect response body

# 3. Generate scaffold
opencli browser init hn/top                    # Creates ~/.opencli/clis/hn/top.ts

# 4. Edit the adapter (fill in func logic)
# - If API found: use fetch() directly (Strategy.PUBLIC or COOKIE)
# - If no API: use page.evaluate() for DOM extraction (Strategy.UI)

# 5. Verify
opencli browser verify hn/top                  # Runs the adapter and shows output

# 6. If verify fails, edit and retry
# 7. Close when done
opencli browser close

Example adapter:

typescript

// ~/.opencli/clis/hn/top.ts
import { cli, Strategy } from '@jackwener/opencli/registry';

cli({
  site: 'hn',
  name: 'top',
  description: 'Top Hacker News stories',
  domain: 'news.ycombinator.com',
  strategy: Strategy.PUBLIC,
  browser: false,
  args: [{ name: 'limit', type: 'int', default: 5 }],
  columns: ['rank', 'title', 'score', 'url'],
  func: async (_page, kwargs) => {
    const limit = Math.min(Math.max(1, kwargs.limit ?? 5), 50);
    const resp = await fetch('https://hacker-news.firebaseio.com/v0/topstories.json');
    const ids = await resp.json();
    return Promise.all(
      ids.slice(0, limit).map(async (id: number, i: number) => {
        const item = await (await fetch(`https://hacker-news.firebaseio.com/v0/item/${id}.json`)).json();
        return { rank: i + 1, title: item.title, score: item.score, url: item.url ?? '' };
      })
    );
  },
});

Save to

~/.opencli/clis/<site>/<command>.ts

→ immediately available as

opencli <site> <command>

Strategy Guide

Strategy	When	browser:
`Strategy.PUBLIC`	Public API, no auth	`false`
`Strategy.COOKIE`	Needs login cookies	`true`
`Strategy.UI`	Direct DOM interaction	`true`

Always prefer API over UI — if you discovered an API during browsing, use

fetch()

directly.

Tips

Always
state
first — never guess element indices, always inspect first
Sessions persist — browser stays open between commands, no need to re-open
Use
eval
for data extraction —
```
eval "JSON.stringify(...)"
```
is faster than multiple
```
get
```
calls
Use
network
to find APIs — JSON APIs are more reliable than DOM scraping
Alias:
```
opencli op
```
is shorthand for
```
opencli browser
```

Common Pitfalls

form.submit()
fails in automation — Don't use

form.submit()

eval

to submit forms. Navigate directly to the search URL instead:

bash

# BAD: form.submit() often silently fails
opencli browser eval "document.querySelector('form').submit()"
# GOOD: construct the URL and navigate
opencli browser open "https://github.com/search?q=opencli&type=repositories"

GitHub DOM changes frequently — Prefer
```
data-testid
```
attributes when available; they are more stable than class names or tag structure.
SPA pages need
wait
before extraction — After
```
open
```
or
```
click
```
on single-page apps, the DOM isn't ready immediately. Always
```
wait selector
```
or
```
wait text
```
before
```
eval
```
.
Use
state
before clicking — Run
```
opencli browser state
```
to inspect available interactive elements and their indices. Never guess indices from memory.
evaluate
runs in browser context —
```
page.evaluate()
```
in adapters executes inside the browser. Node.js APIs (
```
fs
```
,
```
path
```
,
```
process
```
) are NOT available. Use
```
fetch()
```
for network calls, DOM APIs for page data.

Backticks in
page.evaluate
break JSON storage — When writing adapters that will be stored/transported as JSON, avoid template literals inside

page.evaluate

. Use string concatenation or function-style evaluate:

typescript

// BAD: template literal backticks break when adapter is in JSON
page.evaluate(`document.querySelector("${selector}")`)
// GOOD: function-style evaluate
page.evaluate((sel) => document.querySelector(sel), selector)

Troubleshooting

Error	Fix
"Browser not connected"	Run `opencli doctor`
"attach failed: chrome-extension://"	Disable 1Password temporarily
Element not found	`opencli browser scroll down && opencli browser state`
Stale indices after page change	Run `opencli browser state` again to get fresh indices

opencli-browser

NPX Install

Tags

SKILL.md Content

OpenCLI Browser — Browser Automation for AI Agents

Prerequisites

Critical Rules

Command Cost Guide

Action Chaining Rules

Core Workflow

Commands

Navigation

Inspect (free & instant)

Get (free & instant)

Interact

Wait

Extract (free & instant, read-only)

Network (API Discovery)

Sedimentation (Save as CLI)

Session

Example: Extract HN Stories

Example: Fill a Form

Saving as Reusable CLI — Complete Workflow

Step-by-step sedimentation flow:

Example adapter:

Strategy Guide

Tips

Common Pitfalls

Troubleshooting