Server setup in the app

internal/agents/hands.go

@@ -1,10 +1,16 @@
 package agents
 
 import (
+	"context"
+	"encoding/json"
+	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
+	"time"
 
+	"g.fc.run/ai/byre/internal/api"
 	"g.fc.run/ai/byre/internal/mcp"
 )
 
@@ -21,16 +27,8 @@ func (m *Manager) handsDir(sessionID string) string {
 // replayd keys ScreenCaptureKit clients by executable path, so two hands
 // processes run from one path keep cancelling each other's connection.
 func (m *Manager) handsMCP(sessionID, mediaDir string) (mcp.Stdio, error) {
-	src, err := exec.LookPath("byre-hands")
-	if err != nil {
-		return mcp.Stdio{}, err
-	}
-	data, err := os.ReadFile(src)
-	if err != nil {
-		return mcp.Stdio{}, err
-	}
 	dir := m.handsDir(sessionID)
-	err = os.RemoveAll(dir)
+	err := os.RemoveAll(dir)
 	if err != nil {
 		return mcp.Stdio{}, err
 	}
@@ -38,10 +36,56 @@ func (m *Manager) handsMCP(sessionID, mediaDir string) (mcp.Stdio, error) {
 	if err != nil {
 		return mcp.Stdio{}, err
 	}
-	bin := filepath.Join(dir, "byre-hands")
-	err = os.WriteFile(bin, data, 0o755)
+	bin, err := copyHands(dir)
 	if err != nil {
 		return mcp.Stdio{}, err
 	}
 	return mcp.Stdio{Name: "hands", Command: bin, Args: []string{"--media-dir", mediaDir}}, nil
 }
+
+func copyHands(dir string) (string, error) {
+	src, err := exec.LookPath("byre-hands")
+	if err != nil {
+		return "", err
+	}
+	data, err := os.ReadFile(src)
+	if err != nil {
+		return "", err
+	}
+	bin := filepath.Join(dir, "byre-hands")
+	return bin, os.WriteFile(bin, data, 0o755)
+}
+
+func (m *Manager) CheckPermissions(ctx context.Context) ([]api.Permission, error) {
+	err := os.MkdirAll(m.handsRoot, 0o755)
+	if err != nil {
+		return nil, err
+	}
+	dir, err := os.MkdirTemp(m.handsRoot, "check-")
+	if err != nil {
+		return nil, err
+	}
+	defer os.RemoveAll(dir)
+	bin, err := copyHands(dir)
+	if err != nil {
+		return nil, err
+	}
+	ctx, cancel := context.WithTimeout(ctx, 50*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, bin, "check")
+	stderr := strings.Builder{}
+	cmd.Stderr = &stderr
+	out, err := cmd.Output()
+	if ctx.Err() == context.DeadlineExceeded {
+		return nil, fmt.Errorf("byre-hands check didn't finish within 50s; answer macOS's prompt on the server's Mac and check again")
+	}
+	if err != nil {
+		return nil, fmt.Errorf("byre-hands check: %w: %s", err, strings.TrimSpace(stderr.String()))
+	}
+	perms := []api.Permission{}
+	err = json.Unmarshal(out, &perms)
+	if err != nil {
+		return nil, fmt.Errorf("parse byre-hands check: %w", err)
+	}
+	return perms, nil
+}