SEP-1319: Decouple Request Payloads, Remove passthrough iteration, Typecheck fixes

package.json

@@ -72,6 +72,7 @@
         "lint:fix": "eslint src/ --fix && prettier --write .",
         "check": "npm run fetch:spec-types && npm run typecheck && npm run lint",
         "test": "npm run fetch:spec-types && jest",
+        "test:no-spec": "jest --testPathIgnorePatterns=/dist/ --testPathIgnorePatterns=spec\\.types\\.test\\.ts$",
         "start": "npm run server",
         "server": "tsx watch --clear-screen=false scripts/cli.ts server",
         "client": "tsx scripts/cli.ts client"

src/client/index.test.ts

@@ -217,8 +217,7 @@ test('should connect new client to old, supported server version', async () => {
     const client = new Client(
         {
             name: 'new client',
-            version: '1.0',
-            protocolVersion: LATEST_PROTOCOL_VERSION
+            version: '1.0'
         },
         {
             capabilities: {
@@ -279,8 +278,7 @@ test('should negotiate version when client is old, and newer server supports its
     const client = new Client(
         {
             name: 'old client',
-            version: '1.0',
-            protocolVersion: OLD_VERSION
+            version: '1.0'
         },
         {
             capabilities: {
@@ -342,8 +340,7 @@ test("should throw when client is old, and server doesn't support its version",
     const client = new Client(
         {
             name: 'old client',
-            version: '1.0',
-            protocolVersion: OLD_VERSION
+            version: '1.0'
         },
         {
             capabilities: {

src/examples/client/simpleStreamableHttp.ts

@@ -703,7 +703,7 @@ async function getPrompt(name: string, args: Record<string, unknown>): Promise<v
         const promptResult = await client.request(promptRequest, GetPromptResultSchema);
         console.log('Prompt template:');
         promptResult.messages.forEach((msg, index) => {
-            console.log(`  [${index + 1}] ${msg.role}: ${msg.content.text}`);
+            console.log(`  [${index + 1}] ${msg.role}: ${msg.content.type === 'text' ? msg.content.text : JSON.stringify(msg.content)}`);
         });
     } catch (error) {
         console.log(`Error getting prompt ${name}: ${error}`);

src/examples/server/elicitationExample.ts

@@ -177,8 +177,7 @@ mcpServer.registerTool(
                         startTime: {
                             type: 'string',
                             title: 'Start Time',
-                            description: 'Event start time (HH:MM)',
-                            pattern: '^([0-1]?[0-9]|2[0-3]):[0-5][0-9]$'
+                            description: 'Event start time (HH:MM)'
                         },
                         duration: {
                             type: 'integer',
@@ -268,8 +267,7 @@ mcpServer.registerTool(
                         zipCode: {
                             type: 'string',
                             title: 'ZIP/Postal Code',
-                            description: '5-digit ZIP code',
-                            pattern: '^[0-9]{5}$'
+                            description: '5-digit ZIP code'
                         },
                         phone: {
                             type: 'string',

src/integration-tests/taskResumability.test.ts

@@ -151,7 +151,7 @@ describe('Transport resumability', () => {
 
         // Create first client
         const client1 = new Client({
-            id: clientId,
+            title: clientId,
             name: 'test-client',
             version: '1.0.0'
         });
@@ -223,7 +223,7 @@ describe('Transport resumability', () => {
 
         // Create second client with same client ID
         const client2 = new Client({
-            id: clientId,
+            title: clientId,
             name: 'test-client',
             version: '1.0.0'
         });

src/server/elicitation.test.ts

@@ -176,6 +176,7 @@ function testElicitationFlow(validatorProvider: typeof ajvProvider | typeof cfWo
                     age: { type: 'integer', minimum: 0, maximum: 150 },
                     street: { type: 'string' },
                     city: { type: 'string' },
+                    // @ts-expect-error - pattern is not a valid property by MCP spec, however it is making use of the Ajv validator
                     zipCode: { type: 'string', pattern: '^[0-9]{5}$' },
                     newsletter: { type: 'boolean' },
                     notifications: { type: 'boolean' }
@@ -355,6 +356,7 @@ function testElicitationFlow(validatorProvider: typeof ajvProvider | typeof cfWo
                 requestedSchema: {
                     type: 'object',
                     properties: {
+                        // @ts-expect-error - pattern is not a valid property by MCP spec, however it is making use of the Ajv validator
                         zipCode: { type: 'string', pattern: '^[0-9]{5}$' }
                     },
                     required: ['zipCode']

src/server/index.test.ts

@@ -702,9 +702,7 @@ test('should handle server cancelling a request', async () => {
             version: '1.0'
         },
         {
-            capabilities: {
-                sampling: {}
-            }
+            capabilities: {}
         }
     );
 
@@ -763,9 +761,7 @@ test('should handle request timeout', async () => {
             version: '1.0'
         },
         {
-            capabilities: {
-                sampling: {}
-            }
+            capabilities: {}
         }
     );
 

src/server/index.ts

@@ -237,9 +237,9 @@ export class Server<
 
     protected assertRequestHandlerCapability(method: string): void {
         switch (method) {
-            case 'sampling/createMessage':
-                if (!this._capabilities.sampling) {
-                    throw new Error(`Server does not support sampling (required for ${method})`);
+            case 'completion/complete':
+                if (!this._capabilities.completions) {
+                    throw new Error(`Server does not support completions (required for ${method})`);
                 }
                 break;
 

src/server/mcp.test.ts

@@ -1407,7 +1407,12 @@ describe('tool()', () => {
 
         expect(receivedRequestId).toBeDefined();
         expect(typeof receivedRequestId === 'string' || typeof receivedRequestId === 'number').toBe(true);
-        expect(result.content?.[0].text).toContain('Received request ID:');
+        expect(result.content).toEqual(expect.arrayContaining([
+            {
+                type: 'text',
+                text: expect.stringContaining('Received request ID:')
+            }
+        ]));
     });
 
     /***
@@ -1781,7 +1786,12 @@ describe('resource()', () => {
         );
 
         expect(result.contents).toHaveLength(1);
-        expect(result.contents[0].text).toBe('Updated content');
+        expect(result.contents).toEqual(expect.arrayContaining([
+            {
+                text: expect.stringContaining('Updated content'),
+                uri: 'test://resource'
+            }
+        ]));
 
         // Update happened before transport was connected, so no notifications should be expected
         expect(notifications).toHaveLength(0);
@@ -1846,7 +1856,12 @@ describe('resource()', () => {
         );
 
         expect(result.contents).toHaveLength(1);
-        expect(result.contents[0].text).toBe('Updated content');
+        expect(result.contents).toEqual(expect.arrayContaining([
+            {
+                text: expect.stringContaining('Updated content'),
+                uri: 'test://resource/123'
+            }
+        ]));
 
         // Update happened before transport was connected, so no notifications should be expected
         expect(notifications).toHaveLength(0);
@@ -2195,7 +2210,12 @@ describe('resource()', () => {
             ReadResourceResultSchema
         );
 
-        expect(result.contents[0].text).toBe('Category: books, ID: 123');
+        expect(result.contents).toEqual(expect.arrayContaining([
+            {
+                text: expect.stringContaining('Category: books, ID: 123'),
+                uri: 'test://resource/books/123'
+            }
+        ]));
     });
 
     /***
@@ -2556,7 +2576,12 @@ describe('resource()', () => {
 
         expect(receivedRequestId).toBeDefined();
         expect(typeof receivedRequestId === 'string' || typeof receivedRequestId === 'number').toBe(true);
-        expect(result.contents[0].text).toContain('Received request ID:');
+        expect(result.contents).toEqual(expect.arrayContaining([
+            {
+                text: expect.stringContaining(`Received request ID:`),
+                uri: 'test://resource'
+            }
+        ]));
     });
 });
 
@@ -2662,7 +2687,15 @@ describe('prompt()', () => {
         );
 
         expect(result.messages).toHaveLength(1);
-        expect(result.messages[0].content.text).toBe('Updated response');
+        expect(result.messages).toEqual(expect.arrayContaining([
+            {
+                role: 'assistant',
+                content: {
+                    type: 'text',
+                    text: 'Updated response'
+                }
+            }
+        ]));
 
         // Update happened before transport was connected, so no notifications should be expected
         expect(notifications).toHaveLength(0);
@@ -2754,7 +2787,15 @@ describe('prompt()', () => {
         );
 
         expect(getResult.messages).toHaveLength(1);
-        expect(getResult.messages[0].content.text).toBe('Updated: test, value');
+        expect(getResult.messages).toEqual(expect.arrayContaining([
+            {
+                role: 'assistant',
+                content: {
+                    type: 'text',
+                    text: 'Updated: test, value'
+                }
+            }
+        ]));
 
         // Update happened before transport was connected, so no notifications should be expected
         expect(notifications).toHaveLength(0);
@@ -3411,7 +3452,15 @@ describe('prompt()', () => {
 
         expect(receivedRequestId).toBeDefined();
         expect(typeof receivedRequestId === 'string' || typeof receivedRequestId === 'number').toBe(true);
-        expect(result.messages[0].content.text).toContain('Received request ID:');
+        expect(result.messages).toEqual(expect.arrayContaining([
+            {
+                role: 'assistant',
+                content: {
+                    type: 'text',
+                    text: expect.stringContaining(`Received request ID:`)
+                }
+            }
+        ]));
     });
 
     /***
@@ -3513,7 +3562,7 @@ describe('prompt()', () => {
                 })
             }),
             {
-                name: 'Template Name',
+                title: 'Template Name',
                 description: 'Template description',
                 mimeType: 'application/json'
             },

src/server/mcp.ts

@@ -8,7 +8,6 @@ import {
     CallToolResult,
     McpError,
     ErrorCode,
-    CompleteRequest,
     CompleteResult,
     PromptReference,
     ResourceTemplateReference,
@@ -31,7 +30,11 @@ import {
     ServerRequest,
     ServerNotification,
     ToolAnnotations,
-    LoggingMessageNotification
+    LoggingMessageNotification,
+    CompleteRequestPrompt,
+    CompleteRequestResourceTemplate,
+    assertCompleteRequestPrompt,
+    assertCompleteRequestResourceTemplate
 } from '../types.js';
 import { Completable, CompletableDef } from './completable.js';
 import { UriTemplate, Variables } from '../shared/uriTemplate.js';
@@ -217,9 +220,11 @@ export class McpServer {
         this.server.setRequestHandler(CompleteRequestSchema, async (request): Promise<CompleteResult> => {
             switch (request.params.ref.type) {
                 case 'ref/prompt':
+                    assertCompleteRequestPrompt(request);
                     return this.handlePromptCompletion(request, request.params.ref);
 
                 case 'ref/resource':
+                    assertCompleteRequestResourceTemplate(request);
                     return this.handleResourceCompletion(request, request.params.ref);
 
                 default:
@@ -230,7 +235,7 @@ export class McpServer {
         this._completionHandlerInitialized = true;
     }
 
-    private async handlePromptCompletion(request: CompleteRequest, ref: PromptReference): Promise<CompleteResult> {
+    private async handlePromptCompletion(request: CompleteRequestPrompt, ref: PromptReference): Promise<CompleteResult> {
         const prompt = this._registeredPrompts[ref.name];
         if (!prompt) {
             throw new McpError(ErrorCode.InvalidParams, `Prompt ${ref.name} not found`);
@@ -254,7 +259,7 @@ export class McpServer {
         return createCompletionResult(suggestions);
     }
 
-    private async handleResourceCompletion(request: CompleteRequest, ref: ResourceTemplateReference): Promise<CompleteResult> {
+    private async handleResourceCompletion(request: CompleteRequestResourceTemplate, ref: ResourceTemplateReference): Promise<CompleteResult> {
         const template = Object.values(this._registeredResourceTemplates).find(t => t.resourceTemplate.uriTemplate.toString() === ref.uri);
 
         if (!template) {

src/server/title.test.ts

@@ -189,7 +189,12 @@ describe('Title field backwards compatibility', () => {
         // Test reading the resource
         const readResult = await client.readResource({ uri: 'users://123/profile' });
         expect(readResult.contents).toHaveLength(1);
-        expect(readResult.contents[0].text).toBe('Profile data for user 123');
+        expect(readResult.contents).toEqual(expect.arrayContaining([
+            {
+                text: expect.stringContaining('Profile data for user 123'),
+                uri: 'users://123/profile'
+            }
+        ]));
     });
 
     it('should support serverInfo with title', async () => {

src/shared/metadataUtils.ts

@@ -10,18 +10,15 @@ import { BaseMetadata } from '../types.js';
  * For other objects: title → name
  * This implements the spec requirement: "if no title is provided, name should be used for display purposes"
  */
-export function getDisplayName(metadata: BaseMetadata): string {
+export function getDisplayName(metadata: BaseMetadata & { annotations?: { title?: string } }): string {
     // First check for title (not undefined and not empty string)
     if (metadata.title !== undefined && metadata.title !== '') {
         return metadata.title;
     }
 
     // Then check for annotations.title (only present in Tool objects)
-    if ('annotations' in metadata) {
-        const metadataWithAnnotations = metadata as BaseMetadata & { annotations?: { title?: string } };
-        if (metadataWithAnnotations.annotations?.title) {
-            return metadataWithAnnotations.annotations.title;
-        }
+    if (metadata.annotations?.title) {
+        return metadata.annotations.title;
     }
 
     // Finally fall back to name

src/shared/protocol.test.ts

@@ -666,11 +666,13 @@ describe('mergeCapabilities', () => {
 
         const additional: ClientCapabilities = {
             experimental: {
-                feature: true
+                feature: {
+                    featureFlag: true
+                }
             },
             elicitation: {},
             roots: {
-                newProp: true
+                listChanged: true
             }
         };
 
@@ -680,10 +682,11 @@ describe('mergeCapabilities', () => {
             elicitation: {},
             roots: {
                 listChanged: true,
-                newProp: true
             },
             experimental: {
-                feature: true
+                feature: {
+                    featureFlag: true
+                }
             }
         });
     });
@@ -701,7 +704,7 @@ describe('mergeCapabilities', () => {
                 subscribe: true
             },
             prompts: {
-                newProp: true
+                listChanged: true
             }
         };
 
@@ -710,7 +713,6 @@ describe('mergeCapabilities', () => {
             logging: {},
             prompts: {
                 listChanged: true,
-                newProp: true
             },
             resources: {
                 subscribe: true