nc://tab-watchdog

Tab Watchdog: closes stale blank, idle and duplicate Chrome tabs. A Nodecode rewrite of web3blind/hermes-chrome-tab-watchdog by web3blind.

A browser driven by an agent keeps a tab for every page it was sent to, and the blanks, the about:blank windows and the three copies of one url are still there tomorrow. This cell watches one Chromium browser over its DevTools endpoint and says which of its tabs are stale; with your yes it closes them, and never more than it can account for.

A tab is stale when

• it is a blank page (about:blank, a new-tab page) that has been there for blank_minutes;
• it is a second copy of a url another tab already shows, and has sat for duplicate_hours;
• nothing about it -- title or url -- has changed for idle_hours.

A sweep closes at most max_close of them, never the last page a browser has open, and never every blank tab; each one is looked for twice before it is closed and once after, so the answer says what really went. Ages come from the cell's own looks: Chrome does not tell it which tab was clicked, so a page being read whose title never changes does look idle. Run the report first.

Get it

Tell the agent "add the tab-watchdog cell", or run nodecode add nc://tab-watchdog.

Set it up

Start the browser you want watched with a DevTools port, and leave it running:

chrome --remote-debugging-port=9222

Then set the section in /settings, or in ~/.nodecode/config.jsonc:

{
  "tab-watchdog": {
    "endpoint": "http://127.0.0.1:9222", // the browser's DevTools address, loopback only
    "blank_minutes": 30,                 // a blank tab this old is stale
    "duplicate_hours": 2,                // a second copy this old is stale
    "idle_hours": 6,                     // a tab nothing changed in this long is stale
    "max_close": 5,                      // the most one sweep closes
    "auto": false,                       // sweep every sweep_minutes on its own
    "sweep_minutes": 15
  }
}

Only endpoint matters to reach a browser; the rest default as above. A section left out is a cell that starts and does nothing until it is set up.

Use it

The model has two tools, tabs_inspect (the report: every open tab, and which ones a sweep would close) and tabs_sweep (the same, then the close; pass apply false for a dry run). The operator has /tabs -- the report and a dialog whose first row runs the sweep -- and /tabs sweep, and the same verbs from eval:

(tab-watchdog:report)                 ; the page tabs, the stale ones marked
(tab-watchdog:sweep)                  ; what a sweep would close, and why
(tab-watchdog:sweep :apply t)        ; close them; second value: the ids it closed
(tab-watchdog:tabs)                  ; the browser's own /json/list answer, as plists

With auto on, a worker looks every sweep_minutes and says in a notice what it closed. The ages it judges by are kept in a ledger under the home (tab-watchdog/ledger.json), so they survive a restart; it holds a target id, a url, a title and two times, and nothing else.

What the rewrite does not do

• No CDP proxy. The original sat between the harness's browser tools and the browser and read each tool's commands off that proxy to know which tab was in use. Nodecode's browser cells do not dial this cell, so there is nothing to sit between: a tab is judged by its own age here.
• No observer session, no focus script. The original injected a script that reported clicks and focus. This rewrite asks the two DevTools HTTP routes (/json/list, /json/close) and nothing else, so it needs no WebSocket and sees no page content.
• No per-tool leases. There was nothing to lease once the proxy went; the one rule it served -- never close a tab a call is using -- is kept the safe way, by closing as little as possible.
• No cron entry point. auto is the same every-fifteen-minutes sweep, on the cell's own worker, without a crontab to install.

MIT licensed. See NOTICE for what came from the original and what did not.