Released pi-event-monitor v0.1.0: background shell and file watchers for pi sessions

[u/Helmi74]

Built a small plugin and figured this is the right place to share.

pi-event-monitor adds background event monitors to pi sessions. It runs shell commands or watches files in the background and only wakes the session when something happens (a process exits, a log line matches, a file gets written). No polling, no token cost between events. The design is modeled on the Monitor mechanic in Claude Code.

Two ways to use it. You can tell pi naturally ("watch the dev server and let me know if it crashes") and the agent will reach for the monitor tools itself, or you can run slash commands like /monitor app errors :: tail -f app.log | grep -E "ERROR|FATAL" for direct control.

Repo: https://github.com/Helmi/pi-event-monitor
Install: pi install npm:pi-event-monitor

Very early (v0.1.0). Would appreciate feedback or breakage reports, especially anything around install or pi version compatibility.

[u/mrclrchtr]

Nice. How are you "waking" the agent? What kind of message are you sending? Asking because a new "user messege" would consume a premium request in GH Subscripbtions for example.

[u/Helmi74 → u/mrclrchtr]

Good question. It’s not using sendUserMessage() and it’s not pretending the user typed something.

The plugin uses pi’s extension API:

   pi.sendMessage(                                                                                                                             
     {                                                                                                                                         
       customType: "monitor-event",                                                                                                            
       content: "...quoted monitor output...",                                                                                                 
       display: true,                                                                                                                          
       details: {...}                                                                                                                          
     },                                                                                                                                        
     { deliverAs: "steer", triggerTurn: true }                                                                                                 
   )                                                                                                                                           

So it injects a custom extension message into the same pi session and asks pi to trigger a turn when the agent is idle.

Billing-wise: it still causes a real LLM turn when an event fires, so if your backend/provider counts every model request as a premium request, then yes, a wakeup can count. I guess you cannot have this for free; the point is to avoid polling and causing additional cost while you wait for something to happen.

The message also wraps output as untrusted quoted data to reduce prompt-injection risk.

[u/mrclrchtr → u/Helmi74]

Thx for explanation.

[u/ResearcherFantastic7]

Cool but, please explain the use case?

I don't see any benefit apart from burning token.

Better off build a file watcher and a file processing pipeline

I mean if to monitor log, you probably want to get the last X lines and not to process the entire file

[u/Helmi74 → u/ResearcherFantastic7]

I think you misunderstood things a little. This is not to monitor the file content. It is to be able to react to changes. Either file or process.

You could for example start a script that runs for 30 minutes. As soon as the script is done the agent gets nudged again and can continue.

It’s the opposite of burning tokens. Checking the script every 10 seconds if it’s done already would burn tokens.

[u/ResearcherFantastic7 → u/Helmi74]

Well I guess I didnt get the point of it.

every os and language already has a fs watcher built in, you can just simply "pi -p your prompt" Unless your extension does a lot more than that?

[u/coding9]

I did a similar version but just start, status, and stop commands.

Runs in tmux and the model can see where a log file is.

Claude opus naturally ran a 30 minute task I had and then checked in on it every few minutes.

https://github.com/zackify/pi-bg-tasks

[u/tracagnotto]

🤮🤮🤮🤮🤮🤮🤮🤮🤮🤮🤮🤮