Command line

mob3 [flags] [url|file]

With no URL, MOB³ opens the -home target (about:home by default). Input that looks like a search query instead of a URL uses the -search fallback. A local path becomes a file: URL.

Interactive mode starts only when stdin and stdout are TTYs. Otherwise MOB³ falls back to dump mode and prints the rendered page.

Flags

Flag	Default	Meaning
`-dump`	off	Render the page to stdout and exit
`-png`	off	Write a PNG screenshot of the dump to stdout; implies `-dump`
`-width int`	terminal width or 100	Layout width in columns
`-height int`	0	Layout viewport height and output limit; 0 uses the full page (dump/PNG/MCP)
`-graphics string`	`none`	Image mode: `none`, `auto`, `kitty`, `iterm`, `blocks`
`-g string`	`none`	Alias for `-graphics`
`-no-js`	off	Disable page script fetching and execution
`-reader`	off	Start in reader mode
`-dark`	off	Start in dark mode
`-ignore-blocks`	off	Load anti-bot/CAPTCHA pages instead of the blocked page
`-bookmarks string`	none	Import a Netscape bookmark HTML file
`-home string`	`about:home`	Startup and Home-button target
`-js-memory int`	256	JavaScript heap limit in MB; `0` disables the watchdog
`-cache int`	32	In-memory resource cache limit in MB; `0` disables it
`-layout-budget string`	`standard`	Layout limits: `low`, `standard`, `high`, `none`
`-text-scale string`	`auto`	Kitty scaled text: `auto` or `off`
`-color`	off	Force ANSI colors when dumping
`-no-color`	off	Disable ANSI colors in dump mode
`-ua string`	`MOB3/1.0 (+terminal; +https://mob3.net)`	Custom User-Agent
`-search string`	DuckDuckGo HTML endpoint	Search URL template with `%s`; empty disables the fallback
`-mcp`	off	Run the MCP automation server on stdin/stdout
`-version`		Print the version and exit
`-h`, `-help`		Print flags and exit

Run mob3 -h for the exact defaults in your build.

Images and graphics

-graphics=none is the default: no external image downloads and no inline SVG rasterization. When enabled, native terminal graphics are preferred:

kitty graphics protocol
iTerm2 inline images
colored half-block art (▀/▄)

Auto-detection uses environment variables. Under tmux, screen or zellij it falls back to half-block art because the multiplexer usually consumes graphics escapes unless passthrough is configured. -g is an alias for -graphics.

Dump mode always uses half-block art for images that were loaded.

Color and dump mode

-dump prints the whole document height (capped at 20,000 rows) without browser chrome. Color is automatic on a TTY, forced by -color, and disabled by -no-color.

mob3 -dump -width 120 page.html
mob3 -dump -width 120 -no-color https://go.dev
mob3 -dump -color https://example.com

Page height

-height N sets the layout viewport to N rows and limits dump/PNG output to N document rows. This affects position:fixed boxes and other height-dependent layout. -height 0 keeps the full document height. The interactive UI always uses the real terminal height.

mob3 -dump -height 40 -width 120 page.html
mob3 -png -height 40 -width 120 page.html > page.png
mob3 -mcp -width 100 -height 60

PNG screenshots

-png renders the dump as a PNG stream on stdout. It implies -dump, is capped at 2,000 rows, and uses an 8×16 pixel cell with Go Mono glyphs:

mob3 -png -width 120 bbc.com/news > bbc.png
mob3 -png -g blocks -width 120 bbc.com/news > bbc-images.png

Image cells render as colored half-block art. The renderer is text-oriented: CJK and emoji glyphs are missing from the bundled Go Mono font, and there is no browser chrome or true pixel screenshot.

Layout budget

-layout-budget bundles the style/layout deadline and fragment/document-row caps:

Preset	Deadline	Fragments	Rows
`low`	1 s	100,000	80,000
`standard`	2 s	250,000	200,000
`high`	5 s	1,000,000	1,000,000
`none`	disabled	disabled	disabled

none can freeze the UI on hostile or generated pages. The preset is editable in about:config; a zero individual limit disables that check. When a limit is hit, the page renders partially and the status says Page truncated (layout limit).

JavaScript and cache limits

-js-memory sets the per-script/callback heap budget. Every script also runs under a 2-second CPU watchdog. 0 disables the heap watchdog but not the CPU timeout. -no-js disables both script fetching and execution; <noscript> content is then shown.

-cache is a session-only LRU budget for CSS/JS response bodies and decoded images. Nothing is written to disk, and cache hits appear in the ! console.

Home, search and bookmarks

-home sets the page opened at startup and by the ⌂ toolbar button. The -search template receives the URL-escaped query in %s; the default uses the server-rendered DuckDuckGo HTML endpoint. An empty value disables search fallback, so only URL-like input navigates.

-bookmarks FILE imports a Netscape bookmark export (Chrome, Firefox, Safari, Edge). The ★ Bookmarks toolbar button appears only when a bookmark file was loaded. Bookmarks live in memory for the session.

Automation

-mcp starts the headless MCP server instead of the terminal UI:

mob3 -mcp -width 100 about:home

See Automation with MCP for the client configuration, protocol and tools.

`about:config`

The ⚙ toolbar icon opens about:config, a form listing every CLI option and its current value. Editable options change for the session only; startup options are read-only; dump-only colour options do not affect the interactive UI. The top shows the current viewport in characters and pixels (using the terminal's reported cell size, or 8×16 by default). Nothing is persisted.