fix: update the draft wire version to 2026-07-28

README.md

@@ -64,13 +64,13 @@ npx @modelcontextprotocol/conformance client --command "<client-command>" --scen
 - `--command` - The command to run your MCP client (can include flags)
 - `--scenario` - The test scenario to run (e.g., "initialize")
 - `--suite` - Run a suite of tests in parallel: `all`, `core`, `extensions`, `backcompat`, `auth`, `metadata`, `draft` (scenarios targeting the in-progress draft spec), or `sep-835`
-- `--spec-version <version>` - Filter scenarios by spec version (e.g., `2025-11-25`, `DRAFT-2026-v1`; `draft` is accepted as an alias for the current draft identifier). The draft version selects the latest dated release plus any draft-only scenarios. When omitted, the version is inferred from the scenario's spec applicability (draft-only scenarios run at the draft version, everything else at the latest dated release); an explicitly requested version outside a scenario's applicability window skips the scenario (exit 0) unless `--force` is passed
+- `--spec-version <version>` - Filter scenarios by spec version (e.g., `2025-11-25`, `2026-07-28`; `draft` is accepted as an alias for the current draft identifier). The draft version selects the latest dated release plus any draft-only scenarios. When omitted, the version is inferred from the scenario's spec applicability (draft-only scenarios run at the draft version, everything else at the latest dated release); an explicitly requested version outside a scenario's applicability window skips the scenario (exit 0) unless `--force` is passed
 - `--force` - Run a scenario even if it is not applicable at the requested `--spec-version`
 - `--expected-failures <path>` - Path to YAML baseline file of known failures (see [Expected Failures](#expected-failures))
 - `--timeout` - Timeout in milliseconds (default: 30000)
 - `--verbose` - Show verbose output
 
-The framework appends `<server-url>` as an argument to your command and sets the `MCP_CONFORMANCE_SCENARIO` environment variable to the scenario name. For scenarios that require additional context (e.g., client credentials), the `MCP_CONFORMANCE_CONTEXT` environment variable contains a JSON object with scenario-specific data. When `--spec-version` is passed, its resolved value is forwarded to the client process as `MCP_CONFORMANCE_PROTOCOL_VERSION`; example clients can use this value directly as their `protocolVersion`. SDKs that hard-code their protocol version can ignore it. Clients under test must derive the lifecycle from the protocol version they are asked to run: dated versions through `2025-11-25` use the stateful lifecycle (initialize handshake), while the 2026 draft (`DRAFT-2026-v1`) uses the stateless lifecycle (per-request `_meta`).
+The framework appends `<server-url>` as an argument to your command and sets the `MCP_CONFORMANCE_SCENARIO` environment variable to the scenario name. For scenarios that require additional context (e.g., client credentials), the `MCP_CONFORMANCE_CONTEXT` environment variable contains a JSON object with scenario-specific data. When `--spec-version` is passed, its resolved value is forwarded to the client process as `MCP_CONFORMANCE_PROTOCOL_VERSION`; example clients can use this value directly as their `protocolVersion`. SDKs that hard-code their protocol version can ignore it. Clients under test must derive the lifecycle from the protocol version they are asked to run: dated versions through `2025-11-25` use the stateful lifecycle (initialize handshake), while the 2026 draft (`2026-07-28`) uses the stateless lifecycle (per-request `_meta`).
 
 ### Server Testing
 

examples/servers/typescript/everything-server.ts

@@ -1276,15 +1276,15 @@ app.post('/mcp', async (req, res) => {
     }
 
     // Protocol Version Negotiation Matrix (-32004, HTTP 400)
-    if (metaVersion !== 'DRAFT-2026-v1') {
+    if (metaVersion !== '2026-07-28') {
       return res.status(400).json({
         jsonrpc: '2.0',
         id,
         error: {
           code: -32004,
           message: 'UnsupportedProtocolVersionError',
           data: {
-            supported: ['DRAFT-2026-v1'],
+            supported: ['2026-07-28'],
             requested: String(metaVersion)
           }
         }
@@ -1344,7 +1344,7 @@ app.post('/mcp', async (req, res) => {
         jsonrpc: '2.0',
         id,
         result: {
-          supportedVersions: ['DRAFT-2026-v1'],
+          supportedVersions: ['2026-07-28'],
           capabilities: {
             tools: { listChanged: true }, // Explicitly announce dynamic capabilities matching Section 7 expectations
             prompts: { listChanged: true },

examples/servers/typescript/sep-2164-empty-contents.ts

@@ -25,7 +25,7 @@ app.post('/mcp', (req, res) => {
         jsonrpc: '2.0',
         id,
         result: {
-          supportedVersions: ['DRAFT-2026-v1'],
+          supportedVersions: ['2026-07-28'],
           capabilities: { resources: {} },
           serverInfo: { name: 'sep-2164-empty-contents', version: '1.0.0' }
         }

examples/servers/typescript/sep-2322-mrtr-broken-server.ts

@@ -23,7 +23,7 @@ type Handler = (params: Record<string, unknown>) => unknown;
 const handlers: Record<string, Handler> = {};
 
 handlers['server/discover'] = () => ({
-  supportedVersions: ['DRAFT-2026-v1'],
+  supportedVersions: ['2026-07-28'],
   capabilities: {
     tools: {},
     prompts: {},

examples/servers/typescript/sep-2549-no-caching-hints.ts

@@ -26,7 +26,7 @@ app.post('/mcp', (req, res) => {
         jsonrpc: '2.0',
         id,
         result: {
-          supportedVersions: ['DRAFT-2026-v1'],
+          supportedVersions: ['2026-07-28'],
           capabilities: { tools: {}, resources: {}, prompts: {} },
           serverInfo: { name: 'sep-2549-no-caching-hints', version: '1.0.0' }
         }

src/connection/connection.test.ts

@@ -20,8 +20,8 @@ describe('connectFor', () => {
     // version through), so identity with connectStateless no longer holds;
     // assert it did not select the stateful implementation. The wire-level
     // behaviour of the wrapper is covered in stateless.test.ts.
-    expect(connectFor('DRAFT-2026-v1')).not.toBe(connectStateful);
-    expect(connectFor('DRAFT-2026-v1')).not.toBe(connectStateless);
+    expect(connectFor('2026-07-28')).not.toBe(connectStateful);
+    expect(connectFor('2026-07-28')).not.toBe(connectStateless);
   });
 });
 
@@ -64,10 +64,10 @@ describe('connectStateless', () => {
     await conn.request('tools/list');
 
     const [, init] = mockFetch.mock.calls[0];
-    expect(init.headers['MCP-Protocol-Version']).toBe('DRAFT-2026-v1');
+    expect(init.headers['MCP-Protocol-Version']).toBe('2026-07-28');
     const sent = JSON.parse(init.body);
     expect(sent.params._meta['io.modelcontextprotocol/protocolVersion']).toBe(
-      'DRAFT-2026-v1'
+      '2026-07-28'
     );
     expect(
       sent.params._meta['io.modelcontextprotocol/clientInfo']

src/scenarios/client/http-standard-headers.test.ts

@@ -24,7 +24,7 @@ describe('HttpStandardHeadersScenario (SEP-2243) — negative', () => {
         id: 1,
         method: 'initialize',
         params: {
-          protocolVersion: 'DRAFT-2026-v1',
+          protocolVersion: '2026-07-28',
           clientInfo: { name: 'neg-test', version: '0' },
           capabilities: {}
         }

src/scenarios/client/request-metadata.test.ts

@@ -26,7 +26,7 @@ async function badClient(serverUrl: string) {
 }
 
 const goodMeta = {
-  'io.modelcontextprotocol/protocolVersion': 'DRAFT-2026-v1',
+  'io.modelcontextprotocol/protocolVersion': '2026-07-28',
   'io.modelcontextprotocol/clientInfo': { name: 'test', version: '1.0' },
   'io.modelcontextprotocol/clientCapabilities': {}
 };
@@ -70,7 +70,7 @@ async function nonRetryingClient(serverUrl: string) {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
-      'MCP-Protocol-Version': 'DRAFT-2026-v1'
+      'MCP-Protocol-Version': '2026-07-28'
     },
     body: JSON.stringify({
       jsonrpc: '2.0',
@@ -118,7 +118,7 @@ async function malformedCapabilitiesClient(serverUrl: string) {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
-      'MCP-Protocol-Version': 'DRAFT-2026-v1'
+      'MCP-Protocol-Version': '2026-07-28'
     },
     body: JSON.stringify({
       jsonrpc: '2.0',

src/scenarios/server/caching.ts

@@ -99,7 +99,7 @@ Servers MUST include \`ttlMs\` (integer >= 0) and \`cacheScope\` ("public" or "p
     // SEP-2549 only exists in the draft spec, so each cacheable endpoint is
     // queried over the version-appropriate connection. Under --spec-version
     // draft that resolves to the stateless impl (SEP-2575): protocolVersion
-    // DRAFT-2026-v1 plus the cross-cutting _meta and standard headers
+    // 2026-07-28 plus the cross-cutting _meta and standard headers
     // (issue #315).
     let conn: Connection;
     try {

src/scenarios/server/stateless.test.ts

@@ -101,7 +101,7 @@ describe('Stateless Server Scenario Negative Tests', () => {
             jsonrpc: '2.0',
             id: reqBody.id,
             result: {
-              supportedVersions: ['DRAFT-2026-v1'],
+              supportedVersions: ['2026-07-28'],
               capabilities: {},
               serverInfo: { name: 'bad-meta-server', version: '1.0.0' }
             }
@@ -341,7 +341,7 @@ describe('Stateless Server Scenario Negative Tests', () => {
             jsonrpc: '2.0',
             id: reqBody.id,
             result: {
-              supportedVersions: ['DRAFT-2026-v1'],
+              supportedVersions: ['2026-07-28'],
               capabilities: {
                 tools: { listChanged: true },
                 prompts: { listChanged: true }

src/spec-types/SOURCE

@@ -1 +1 @@
-modelcontextprotocol@33c3724972e6a87a8ad153e3f8a0d4714b0b9536
+modelcontextprotocol@0168c57fc74aba6e6dcf8f0b7191db3caaa5ad65