Use ldflags first to get version info, then fall back to VCS info

default.nix

@@ -15,6 +15,7 @@ pkgs.buildGoModule rec {
     "-w"
     "-X main.Version=${version}"
     "-X main.Commit=${gitRevision}"
+    "-X main.BuildTime=${toString buildTime}"
   ];
   meta = {
     description = "Nidus Sync";

version/version.go

@@ -2,9 +2,18 @@ package version
 
 import (
 	"runtime/debug"
+	"strconv"
 	"time"
 )
 
+// These will be set by ldflags at build time
+var (
+	Version    = "dev"
+	Commit     = ""
+	BuildTime  = "0"
+	IsModified = "false"
+)
+
 type VersionInfo struct {
 	BuildTime  time.Time `json:"build_time"`
 	IsModified bool      `json:"is_modified"`
@@ -12,12 +21,25 @@ type VersionInfo struct {
 }
 
 func Get() VersionInfo {
+	// Try ldflags first (set by Nix build)
+	if Commit != "" && Commit != "unknown" {
+		var buildTime time.Time
+		if timestamp, err := strconv.ParseInt(BuildTime, 10, 64); err == nil && timestamp > 0 {
+			buildTime = time.Unix(timestamp, 0)
+		}
+
+		return VersionInfo{
+			Revision:   Commit,
+			BuildTime:  buildTime,
+			IsModified: IsModified == "true",
+		}
+	}
+
+	// Fallback to debug.ReadBuildInfo() for development
 	info, ok := debug.ReadBuildInfo()
 	if !ok {
 		return VersionInfo{
-			BuildTime:  time.Now(),
-			IsModified: false,
-			Revision:   "unknown",
+			Revision: "unknown",
 		}
 	}