fixes task build on windows (#98)

resolves #79

Author: jonathansampson

cmd/build/main.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/docker/mcp-registry/internal/mcp"
@@ -81,6 +82,19 @@ func run(ctx context.Context, name string, listTools bool, pullCommunity bool) e
 	return nil
 }
 
+func buildDockerEnv(additionalEnv ...string) []string {
+	env := []string{"PATH=" + os.Getenv("PATH")}
+	
+	// On Windows, Docker also needs ProgramW6432
+	// See https://github.com/docker/mcp-registry/issues/79 for more details
+	programW6432 := os.Getenv("ProgramW6432")
+	if runtime.GOOS == "windows" && programW6432 != "" {
+		env = append(env, "ProgramW6432="+programW6432)
+	}
+	
+	return append(env, additionalEnv...)
+}
+
 func buildMcpImage(ctx context.Context, server servers.Server) error {
 	projectURL := server.Source.Project
 	branch := server.Source.Branch
@@ -115,10 +129,10 @@ func buildMcpImage(ctx context.Context, server servers.Server) error {
 
 	if token != "" {
 		cmd = exec.CommandContext(ctx, "docker", "buildx", "build", "--secret", "id=GIT_AUTH_TOKEN", "-f", server.GetDockerfile(), "-t", "check", "-t", server.Image, "--label", "org.opencontainers.image.revision="+sha, gitURL)
-		cmd.Env = []string{"GIT_AUTH_TOKEN=" + token, "PATH=" + os.Getenv("PATH")}
+		cmd.Env = buildDockerEnv("GIT_AUTH_TOKEN=" + token)
 	} else {
 		cmd = exec.CommandContext(ctx, "docker", "buildx", "build", "-f", server.GetDockerfile(), "-t", "check", "-t", server.Image, "--label", "org.opencontainers.image.revision="+sha, gitURL)
-		cmd.Env = []string{"PATH=" + os.Getenv("PATH")}
+		cmd.Env = buildDockerEnv()
 	}
 
 	cmd.Dir = os.TempDir()