diff --git a/internal/mcp/server_test.go b/internal/mcp/server_test.go
index ba94b91e..4ed0d47e 100644
--- a/internal/mcp/server_test.go
+++ b/internal/mcp/server_test.go
@@ -98,8 +98,8 @@ func TestOpenAIFileMetadataMatchesDeclaredSchemas(t *testing.T) {
 			if !ok {
 				t.Fatalf("%s file input path %q missing from input schema", def.Name, path)
 			}
-			if property["type"] != "string" || property["format"] != "binary" {
-				t.Fatalf("%s file input %q must be string/binary: %#v", def.Name, path, property)
+			if property["type"] != "object" || property["additionalProperties"] != true {
+				t.Fatalf("%s file input %q must be an open object: %#v", def.Name, path, property)
 			}
 		}
 		if len(def.FileArgRewritePaths) > 0 {
diff --git a/internal/tool/media/contract.go b/internal/tool/media/contract.go
index fd03255a..9507c6dd 100644
--- a/internal/tool/media/contract.go
+++ b/internal/tool/media/contract.go
@@ -52,7 +52,7 @@ func InputSchema(name string) (map[string]any, bool) {
 		}
 		return schema, true
 	case ToolFilePublish:
-		props["file"] = map[string]any{"type": "string", "format": "binary", "description": "Top-level file parameter. Connector runtimes should pass the mounted local path when available."}
+		props["file"] = toolcontract.OpenObject("Top-level connector file object. Connector runtimes may rewrite this object with mounted local-path metadata before the tool call reaches AgentDock.")
 		props["path"] = stringProp("Local file or directory path visible to this AgentDock instance. Relative paths resolve from ~/AgentDock.")
 		props["retention_seconds"] = boundedIntProp("Signed URL retention seconds. Zero uses the default 86400 and values are capped at 604800.", 0, int(publicartifacts.MaxRetention/time.Second))
 	default:
diff --git a/internal/tool/media/request.go b/internal/tool/media/request.go
index e4229f89..b0d807a9 100644
--- a/internal/tool/media/request.go
+++ b/internal/tool/media/request.go
@@ -24,7 +24,8 @@ type ViewImageRequest struct {
 	Crop            *CropRequest `json:"crop,omitempty"`
 }
 
-// FilePublishRequest.File 是 connector 文件重写产生的动态叶子；Path 是普通本地路径入口。
+// FilePublishRequest.File 是 connector 文件重写产生的动态对象；Path 是普通本地路径入口。
+// File 保持 any 以兼容不同 connector 注入的文件对象形状，以及旧客户端仍可能发送的路径字符串。
 type FilePublishRequest struct {
 	File             any    `json:"file,omitempty"`
 	Path             string `json:"path,omitempty"`