fix: mcp server media sending

internal/infrastructure/mcpserver/server.go

@@ -6,12 +6,15 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"mime"
 	"mime/multipart"
 	"net/http"
+	"net/textproto"
 	"net/url"
 	"os"
 	"path/filepath"
 	"strconv"
+	"strings"
 
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
@@ -228,7 +231,14 @@ func (s *server) uploadMedia(ctx context.Context, _ *mcp.CallToolRequest, in upl
 	}
 	var form bytes.Buffer
 	writer := multipart.NewWriter(&form)
-	part, err := writer.CreateFormFile("file", name)
+	contentType, err := uploadMediaType(name)
+	if err != nil {
+		return nil, nil, err
+	}
+	header := make(textproto.MIMEHeader)
+	header.Set("Content-Disposition", mime.FormatMediaType("form-data", map[string]string{"name": "file", "filename": name}))
+	header.Set("Content-Type", contentType)
+	part, err := writer.CreatePart(header)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -241,6 +251,21 @@ func (s *server) uploadMedia(ctx context.Context, _ *mcp.CallToolRequest, in upl
 	return result(s.client.Do(ctx, http.MethodPost, "/v1/media/", nil, form.Bytes(), writer.FormDataContentType()))
 }
 
+func uploadMediaType(filename string) (string, error) {
+	switch strings.ToLower(filepath.Ext(filename)) {
+	case ".png":
+		return "image/png", nil
+	case ".jpg", ".jpeg":
+		return "image/jpeg", nil
+	case ".webp":
+		return "image/webp", nil
+	case ".svg":
+		return "image/svg+xml", nil
+	default:
+		return "", fmt.Errorf("filename must end in .png, .jpg, .jpeg, .webp or .svg")
+	}
+}
+
 func uploadContent(in uploadMediaInput) (string, []byte, error) {
 	switch {
 	case in.Path != "" && in.Base64 != "":