From b0e19126e40c6e49678f48e31ffba8024e87b228 Mon Sep 17 00:00:00 2001
From: Daniel Cazzulino <daniel@cazzulino.com>
Date: Sat, 24 Oct 2026 03:33:52 -0300
Subject: [PATCH] Set NDX_LAUNCHED so a launched tool can tell ndx started it.

---
 src/Tests/ToolLauncherTests.cs  | 1 +
 src/ndx/ProcessStartSettings.cs | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Tests/ToolLauncherTests.cs b/src/Tests/ToolLauncherTests.cs
index 7320f23..999e18e 100644
--- a/src/Tests/ToolLauncherTests.cs
+++ b/src/Tests/ToolLauncherTests.cs
@@ -56,5 +56,6 @@ public void ToStartInfo_preserves_no_shell_and_no_redirect()
         Assert.False(start.RedirectStandardOutput);
         Assert.False(start.RedirectStandardError);
         Assert.Equal(["--flag"], start.ArgumentList.ToArray());
+        Assert.Equal("1", start.Environment["NDX_LAUNCHED"]);
     }
 }
diff --git a/src/ndx/ProcessStartSettings.cs b/src/ndx/ProcessStartSettings.cs
index edbaf53..9a27a7c 100644
--- a/src/ndx/ProcessStartSettings.cs
+++ b/src/ndx/ProcessStartSettings.cs
@@ -4,7 +4,8 @@ namespace ndx;
 
 /// <summary>
 /// Process start settings for the downloaded tool. ndx always starts the child
-/// without a shell and with inherited standard in/out/error.
+/// without a shell, with inherited standard in/out/error, and with
+/// <c>NDX_LAUNCHED=1</c> so the child can tell it was started by ndx.
 /// </summary>
 public sealed record ProcessStartSettings
 {
@@ -33,6 +34,8 @@ public ProcessStartInfo ToStartInfo()
         foreach (var argument in Arguments)
             start.ArgumentList.Add(argument);
 
+        start.Environment["NDX_LAUNCHED"] = "1";
+
         return start;
     }
 }