Axial
Repository F# setup
open System
open System.IO
open System.Threading
open System.Threading.Tasks
open Axial
open Axial.Layers
open Axial.Console
open Axial.FileSystem
open Axial.Hosting
open Axial.Hosting.Browser
open Axial.Hosting.Node
open Axial.HttpClient
open Axial.PlatformService
open Axial.Process
open Axial.State
open Axial.Telemetry
open Axial.Telemetry.JavaScript

Process.run fails when startup, timeout, cancellation, I/O, or a stage success policy fails:

match exit with
| Exit.Failure(Cause.Fail(ProcessError.StartFailed failure)) ->
    eprintfn "could not start %s: %s" failure.Command failure.Message
| Exit.Failure(Cause.Fail(ProcessError.TimedOut failure)) ->
    eprintfn "%s exceeded %O" failure.Specification failure.Timeout
| Exit.Failure(Cause.Fail(ProcessError.StageFailed failure)) ->
    eprintfn "stage %d exited %d" failure.Stage.Stage failure.Stage.ExitCode
| _ -> ()
`ProcessError.describe` formats a redacted diagnostic. `ProcessError.exitCode` maps stage failure to its native exit code, timeout to 124, cancellation to 130, and other failures to 1.

Successful execution returns ProcessResult, including exact captured bytes, decoded text, every stage exit code, start times, durations, and bounded stderr tails. A configured successCodes set determines whether each stage succeeds.

let! result = specification |> Process.run

for stage in result.Stages do
    printfn "[%d] %s => %d (%O)" stage.Stage stage.Command stage.ExitCode stage.Duration
Timeout is specification policy. The Flow runtime races the execution, interrupts the losing workflow, waits for native cleanup, and then returns `ProcessError.TimedOut`. Caller cancellation follows the same tree-termination path and returns `ProcessError.Canceled` from the process interpreter.