feat: export method names as consts

Author: idosal

src/spec.types.ts

@@ -548,3 +548,38 @@ export interface McpUiToolMeta {
    */
   visibility?: McpUiToolVisibility[];
 }
+
+/**
+ * Method string constants for MCP UI protocol messages.
+ *
+ * These constants provide a type-safe way to check message methods without
+ * accessing internal Zod schema properties. External libraries should use
+ * these constants instead of accessing `schema.shape.method._def.values[0]`.
+ *
+ * @example
+ * ```typescript
+ * import { MCP_UI_SANDBOX_PROXY_READY_METHOD } from '@modelcontextprotocol/ext-apps';
+ *
+ * if (event.data.method === MCP_UI_SANDBOX_PROXY_READY_METHOD) {
+ *   // Handle sandbox proxy ready notification
+ * }
+ * ```
+ */
+export const MCP_UI_OPEN_LINK_METHOD = "ui/open-link";
+export const MCP_UI_MESSAGE_METHOD = "ui/message";
+export const MCP_UI_SANDBOX_PROXY_READY_METHOD =
+  "ui/notifications/sandbox-proxy-ready";
+export const MCP_UI_SANDBOX_RESOURCE_READY_METHOD =
+  "ui/notifications/sandbox-resource-ready";
+export const MCP_UI_SIZE_CHANGED_METHOD = "ui/notifications/size-changed";
+export const MCP_UI_TOOL_INPUT_METHOD = "ui/notifications/tool-input";
+export const MCP_UI_TOOL_INPUT_PARTIAL_METHOD =
+  "ui/notifications/tool-input-partial";
+export const MCP_UI_TOOL_RESULT_METHOD = "ui/notifications/tool-result";
+export const MCP_UI_TOOL_CANCELLED_METHOD = "ui/notifications/tool-cancelled";
+export const MCP_UI_HOST_CONTEXT_CHANGED_METHOD =
+  "ui/notifications/host-context-changed";
+export const MCP_UI_RESOURCE_TEARDOWN_METHOD = "ui/resource-teardown";
+export const MCP_UI_INITIALIZE_METHOD = "ui/initialize";
+export const MCP_UI_INITIALIZED_METHOD = "ui/notifications/initialized";
+export const MCP_UI_REQUEST_DISPLAY_MODE_METHOD = "ui/request-display-mode";

src/types.ts

@@ -12,6 +12,20 @@
 // Re-export all types from spec.types.ts
 export {
   LATEST_PROTOCOL_VERSION,
+  MCP_UI_OPEN_LINK_METHOD,
+  MCP_UI_MESSAGE_METHOD,
+  MCP_UI_SANDBOX_PROXY_READY_METHOD,
+  MCP_UI_SANDBOX_RESOURCE_READY_METHOD,
+  MCP_UI_SIZE_CHANGED_METHOD,
+  MCP_UI_TOOL_INPUT_METHOD,
+  MCP_UI_TOOL_INPUT_PARTIAL_METHOD,
+  MCP_UI_TOOL_RESULT_METHOD,
+  MCP_UI_TOOL_CANCELLED_METHOD,
+  MCP_UI_HOST_CONTEXT_CHANGED_METHOD,
+  MCP_UI_RESOURCE_TEARDOWN_METHOD,
+  MCP_UI_INITIALIZE_METHOD,
+  MCP_UI_INITIALIZED_METHOD,
+  MCP_UI_REQUEST_DISPLAY_MODE_METHOD,
   type McpUiTheme,
   type McpUiDisplayMode,
   type McpUiStyleVariableKey,