New test: UrlElicitationRequiredError thrown from tool is returned verbatim

Author: nbarbettini

src/server/mcp.test.ts

@@ -15,7 +15,9 @@ import {
     LoggingMessageNotificationSchema,
     type Notification,
     ReadResourceResultSchema,
-    type TextContent
+    type TextContent,
+    UrlElicitationRequiredError,
+    ErrorCode
 } from '../types.js';
 import { completable } from './completable.js';
 import { McpServer, ResourceTemplate } from './mcp.js';
@@ -1618,6 +1620,60 @@ describe('tool()', () => {
         );
     });
 
+    /***
+     * Test: URL Elicitation Required Error Propagation
+     */
+    test('should propagate UrlElicitationRequiredError to client callers', async () => {
+        const mcpServer = new McpServer({
+            name: 'test server',
+            version: '1.0'
+        });
+
+        const client = new Client(
+            {
+                name: 'test client',
+                version: '1.0'
+            },
+            {
+                capabilities: {
+                    elicitation: {
+                        url: {}
+                    }
+                }
+            }
+        );
+
+        const elicitationParams = {
+            mode: 'url' as const,
+            elicitationId: 'elicitation-123',
+            url: 'https://mcp.example.com/connect',
+            message: 'Authorization required'
+        };
+
+        mcpServer.tool('needs-authorization', async () => {
+            throw new UrlElicitationRequiredError([elicitationParams], 'Confirmation required');
+        });
+
+        const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair();
+
+        await Promise.all([client.connect(clientTransport), mcpServer.server.connect(serverTransport)]);
+
+        await client
+            .callTool({
+                name: 'needs-authorization'
+            })
+            .then(() => {
+                throw new Error('Expected callTool to throw UrlElicitationRequiredError');
+            })
+            .catch(error => {
+                expect(error).toBeInstanceOf(UrlElicitationRequiredError);
+                if (error instanceof UrlElicitationRequiredError) {
+                    expect(error.code).toBe(ErrorCode.UrlElicitationRequired);
+                    expect(error.elicitations).toEqual([elicitationParams]);
+                }
+            });
+    });
+
     /***
      * Test: Tool Registration with _meta field
      */