Chrest: healthier window and tab hygiene

---

Chrest is a CLI tool and browser extension that lets you manage Chrome and Firefox via REST. Chrest was inspired by (and somewhat forked from) TabFS.

Chrest consists of two parts:

1. Browser Extension: (/extension)
2. Native Messaging Host & CLI Client: chrest (/)

Examples

Note: to keep Chrest slim, Chrest does not include pretty-print JSON or HTTP Request construction, but there are other wonderful tools you can use for that like http and jq.

• Getting all windows and tabs:

  $ http --ignore-stdin --offline localhost/windows |
  $   chrest client |
  $   jq
  > [
  >   {
  >     "alwaysOnTop": false,
  >     "focused": false,
  >     "height": 1400,
  >     "id": 1531273373,
  >     "incognito": false,
  >     "left": 1411,
  >     "state": "normal",
  >     "tabs": [
  >       {
  >         "active": true,
  >         "audible": false,
  >         "autoDiscardable": true,
  >         "discarded": false,
  >         "favIconUrl": "https://github.githubassets.com/favicons/favicon.svg",
  >         "groupId": -1,
  >         "height": 1279,
  >         "highlighted": true,
  >         "id": 1531273367,
  >         "incognito": false,
  >         "index": 0,
  >         "mutedInfo": {
  >           "muted": false
  >         },
  >         "pinned": false,
  >         "selected": true,
  >         "status": "complete",
  >         "title": "friedenberg/chrest",
  >         "url": "https://github.com/friedenberg/chrest",
  >         "width": 1128,
  >         "windowId": 1531273373
  >       }
  >     ],
  >     "top": 20,
  >     "type": "normal",
  >     "width": 1128
  >   }
  > ]
  

• Creating a new window with some URL's:

  $ http --ignore-stdin --offline localhost/windows \
  $   urls[]=https://github.com/friedenberg/chrest |
  $   chrest client |
  $   jq
  > {
  >   "alwaysOnTop": false,
  >   "focused": false,
  >   "height": 1400,
  >   "id": 1531273390,
  >   "incognito": false,
  >   "left": 0,
  >   "state": "normal",
  >   "tabs": [
  >     {
  >       "active": true,
  >       "audible": false,
  >       "autoDiscardable": true,
  >       "discarded": false,
  >       "groupId": -1,
  >       "height": 1279,
  >       "highlighted": true,
  >       "id": 1531273391,
  >       "incognito": false,
  >       "index": 0,
  >       "lastAccessed": 1708099951989.452,
  >       "mutedInfo": {
  >         "muted": false
  >       },
  >       "pendingUrl": "https://github.com/friedenberg/chrest",
  >       "pinned": false,
  >       "selected": true,
  >       "status": "loading",
  >       "title": "",
  >       "url": "",
  >       "width": 1128,
  >       "windowId": 1531273390
  >     }
  >   ],
  >   "top": 0,
  >   "type": "normal",
  >   "width": 1128
  > }
  

• Closing a window:

  $ http --ignore-stdin --offline DELETE localhost/windows/1531273390 |
  $   chrest client |
  $   jq
  

Capturing pages

chrest capture drives a headless browser to render a URL and returns the result in the format you ask for. Output streams to stdout by default; use --output <path> to write atomically to a file.

Eleven formats are supported:

Format	Media type	Notes
pdf	application/pdf	flags: --landscape, --no-headers, --background
screenshot-png	image/png	flag: --full-page
screenshot-jpeg	image/jpeg	flags: --quality, --full-page
mhtml	multipart/related	not yet functional
a11y	application/json	not yet functional; accessibility tree
text	text/plain; charset=utf-8	document.body.innerText
html-monolith	text/html; charset=utf-8	self-contained HTML with assets inlined as data: URIs (via the monolith CLI)
html-outer	text/html; charset=utf-8	raw document.documentElement.outerHTML — no asset inlining
markdown-full	text/markdown; charset=utf-8	whole rendered DOM → markdown
markdown-reader	text/markdown; charset=utf-8	Readability-extracted main content → markdown
markdown-selector	text/markdown; charset=utf-8	CSS-selector scoped; requires --selector <css>

Backend is headless Firefox via WebDriver BiDi.

Examples:

• PDF to stdout:

  $ chrest capture --format pdf --url https://example.com > page.pdf
  

• Full-page PNG to a file, atomically:

  $ chrest capture --format screenshot-png --full-page \
  $   --url https://en.wikipedia.org/wiki/Markdown \
  $   --output wiki.png
  

• Self-contained archive of a blog post:

  $ chrest capture --format html-monolith \
  $   --url https://simonwillison.net/ \
  $   --output blog.html
  

• Reader-mode markdown (boilerplate stripped):

  $ chrest capture --format markdown-reader \
  $   --url https://simonwillison.net/2026/Feb/15/gwtar/
  

• Markdown scoped to one element:

  $ chrest capture --format markdown-selector --selector "#bodyContent" \
  $   --url https://en.wikipedia.org/wiki/Markdown
  

Batch captures

chrest capture-batch implements the Web Capture Archive Protocol (RFC 0001) for pipelines that need multiple captures of the same page in a single pass, with content-addressed artifacts and a JSON result envelope.

$ echo '{
    "schema":   "web-capture-archive/v1",
    "writer":   {"cmd": ["your-content-addressed-writer"]},
    "url":      "https://en.wikipedia.org/wiki/Ferris_wheel",
    "defaults": {"browser": "firefox", "split": false},
    "captures": [
      {"name": "pdf",     "format": "pdf"},
      {"name": "md",      "format": "markdown-reader"},
      {"name": "archive", "format": "html-monolith"}
    ]
  }' | chrest capture-batch | jq

The writer command is invoked once per artifact; chrest streams the bytes to its stdin and expects a one-line JSON response of the form {"id": "<content-addressed-id>", "size": N}. The final stdout JSON is a result envelope with one entry per capture, each pointing at the writer's returned IDs.

See docs/features/0001-web-page-capture.md for design intent, backend trade-offs, and a full list of known limitations.

Installation

1. Install the CLI

Choose one:

• Go: go install code.linenisgreat.com/chrest/go/cmd/chrest@latest
• Nix: nix profile install github:friedenberg/chrest

2. Install the browser extension

Chrome:

1. Go to chrome://extensions/
2. Enable Developer mode (top-right corner)
3. Click "Load unpacked" and select the extension/dist-chrome/ folder

Firefox:

1. Go to about:debugging#/runtime/this-firefox
2. Click "Load Temporary Add-on" and select any file in extension/dist-firefox/

3. Initialize chrest

$ chrest init --browser chrome

Or for Firefox:

$ chrest init --browser firefox

If you omit --browser, chrest will prompt you interactively.

4. Verify

Reload the extension in your browser, then:

$ chrest list-windows

Known Issues

• Chrome will turn off service workers when there are no windows left, so at least 1 window needs to exist for chrest to be running. I may add a fallback in chrest to use AppleScript to create a new window if the server is not running.