ensure provider working directories exist

internal/shared/tools.go

@@ -30,6 +30,9 @@ func RunProviderCommand(
 	if command == "" {
 		return "", fmt.Errorf("unsupported provider: %s", provider)
 	}
+	if err := ensureWorkingDirectoryExists(workingDirectory); err != nil {
+		return "", err
+	}
 	cmd := exec.CommandContext(ctx, command, args...)
 	if strings.TrimSpace(workingDirectory) != "" {
 		cmd.Dir = strings.TrimSpace(workingDirectory)
@@ -59,6 +62,30 @@ func RunProviderCommand(
 	return output, nil
 }
 
+func ensureWorkingDirectoryExists(workingDirectory string) error {
+	workingDirectory = strings.TrimSpace(workingDirectory)
+	if workingDirectory == "" {
+		return nil
+	}
+	if info, err := os.Stat(workingDirectory); err == nil {
+		if info.IsDir() {
+			return nil
+		}
+		return fmt.Errorf("working directory is not a directory: %s", workingDirectory)
+	}
+	if err := os.MkdirAll(workingDirectory, 0o755); err != nil {
+		return fmt.Errorf("ensure working directory %s: %w", workingDirectory, err)
+	}
+	info, err := os.Stat(workingDirectory)
+	if err != nil {
+		return fmt.Errorf("verify working directory %s: %w", workingDirectory, err)
+	}
+	if !info.IsDir() {
+		return fmt.Errorf("working directory is not a directory: %s", workingDirectory)
+	}
+	return nil
+}
+
 func NormalizeProviderWorkingDirectory(provider, requested string) (string, string) {
 	requested = strings.TrimSpace(requested)
 	if requested == "" {

internal/shared/tools_test.go

@@ -1,6 +1,8 @@
 package shared
 
 import (
+	"context"
+	"os"
 	"path/filepath"
 	"testing"
 )
@@ -52,3 +54,29 @@ func TestResolveProviderCommandSupportsHermes(t *testing.T) {
 		t.Fatalf("unexpected hermes args: %#v", args)
 	}
 }
+
+func TestRunProviderCommandCreatesMissingWorkingDirectory(t *testing.T) {
+	workspaceRoot := filepath.Join(t.TempDir(), "owners", "local", "user", "thread-1")
+	scriptPath := filepath.Join(t.TempDir(), "hermes.sh")
+	if err := os.WriteFile(scriptPath, []byte("#!/bin/sh\necho ok\n"), 0o755); err != nil {
+		t.Fatalf("write script: %v", err)
+	}
+	t.Setenv("ACP_HERMES_BIN", scriptPath)
+
+	output, err := RunProviderCommand(
+		context.Background(),
+		"hermes",
+		"sonnet",
+		"hello world",
+		workspaceRoot,
+	)
+	if err != nil {
+		t.Fatalf("RunProviderCommand() error = %v", err)
+	}
+	if output != "ok" {
+		t.Fatalf("RunProviderCommand() output = %q, want %q", output, "ok")
+	}
+	if info, err := os.Stat(workspaceRoot); err != nil || !info.IsDir() {
+		t.Fatalf("expected working directory to be created, stat err=%v info=%v", err, info)
+	}
+}