errand--

Run it elsewhere.

Put errand -- in front of the command you'd normally run. Your working tree goes over, uncommitted edits included. The logs stream back and you get the exit code. No remote clone to babysit.

$ brew install lydakis/errand/errand
Set it up Read the source on GitHub
Line drawing of a man at a 1990s computer whose ghostly double floats through a cloud to type at a second computer far away.
Running it elsewhere is a lot like astral projection. Adapted from Figure 7.1 in Daniel P. Dern's The Internet Guide for New Users (1994).

Examples

~/myapp 

          

          

        


        

          

            Why I built it
          

          

            

              I build Atlas, a
              NixOS host for agents, on an Apple Silicon Mac. Its VM tests need
              /dev/kvm, which a Mac can't give you, so they crawled
              under emulated QEMU. My Linux box had KVM and nothing to do.
            

            

              I didn't want to commit half-done work, SSH in, pull, run and copy
              results back every time. So I wrote errand. Now the tests run on
              the Linux box, straight from my uncommitted tree.
            

            
These days my coding agents use it more than I do.

            George
          

        


        

          
How it works

          
    
            
  1. 
              
    Your files go over
    
              
    
                Tracked files and uncommitted edits. Git-ignored files stay
                home, and repeat runs ship only what changed.
              
    
            
    2. 
            
  2. 
              
    It runs over there
    
              
    
                Each job gets a fresh workspace on the runner. Your local files
                stay untouched.
              
    
            
    3. 
            
  3. 
              
    Output comes back
    
              
    
                Logs stream back with the real exit code.
                Ctrl-C stops the job, Ctrl-D detaches.
              
    
            
    4. 
            
  4. 
              
    Changes come back
    
              
    
                Changed files are kept, even on failure.
                errand fetch --apply brings them into your
                checkout.
              
    
            
    5. 
          

        


        

          

            
How fast it is

            
Medians from the scoreboard in the repo.

          

          

            

              228 ms
              

                From saving a file on a laptop to it showing up on a Linux
                runner with push --watch, 1,000-file checkout.
              

            

            

              230 ms
              

                Fetching and applying a finished job's changes from that runner,
                1,000-file checkout.
              

            

            

              6.2→1.0 s
              

                Applying 128 changed files across 128 directories on macOS,
                before and after the 0.5 apply work.
              

            

          

        


        

          

            
More

            

              

                

                  errand --where 'os=linux,go' -- go test ./...
                

                
Pick any runner that has what the command needs.

              

              

                
errand --on local -- make test

                
Run in a separate workspace on this machine.

              

              

                

                  errand push --workspace dev --watch --apply
                

                
Keep a workspace on the runner in sync while you edit.

              

              

                

                  errand --cache compiler=target -- cargo test
                

                
Reuse the runner's build cache between jobs.

              

              

                
.errand.toml

                
Save a project's usual runner, caches and ports.

              

              

                
errand doctor

                
Tells you why a runner isn't answering.

              

            

          

          

            
Good to know

            
    
              
  • 
                It runs commands directly on machines you control. It's not a
                sandbox.
              
    • 
              
  • 
                Commands run without a terminal attached. Run coding agents in
                their noninteractive mode.
              
    • 
              
  • Install the same errand version on both ends.
    • 
              
  • 
                A Windows PC can run jobs but can't send them yet.
                experimental
              
    • 
              
  • No telemetry. MIT licensed.
    • 
            

          

        


        

          
Set it up

          
Both machines on the same Tailscale network, or plain SSH.

          
    
            
  1. 
              
    On both machines
    
              
    brew install lydakis/errand/errand
    
              
    
                Or grab a binary from
                GitHub Releases.
              
    
            
    2. 
            
  2. 
              
    
                On the machine that runs things
              
    
              
    errand setup
    
              
    Installs and starts the runner service.
    
            
    3. 
            
  3. 
              
    On your laptop
    
              
    errand peers discover
# then run the line it prints, like:
errand peers add mac-mini YOUR_RUNNER_HOSTNAME
    
              
    
                Using SSH instead?
                errand peers add mac-mini YOUR_SSH_HOST --ssh
              
    
            
    4. 
            
  4. 
              
    From any Git checkout
    
              
    errand -- make test
    
              
    
                The first runner you add is the default. Pick another with
                --on NAME.
              
    
            
    5. 
          

          

            Windows runner (experimental)
            
scoop bucket add errand https://github.com/lydakis/scoop-errand
scoop install errand
errand setup

            

              Runs jobs sent from a Mac or Linux machine over Tailscale. See
              what works so far.