chore: enter beta prerelease mode

.changeset/beta-release.md

@@ -0,0 +1,16 @@
+---
+'@modelcontextprotocol/server': patch
+'@modelcontextprotocol/client': patch
+'@modelcontextprotocol/core': patch
+'@modelcontextprotocol/server-legacy': patch
+'@modelcontextprotocol/codemod': patch
+'@modelcontextprotocol/express': patch
+'@modelcontextprotocol/hono': patch
+'@modelcontextprotocol/fastify': patch
+'@modelcontextprotocol/node': patch
+---
+
+First beta release of SDK v2 with support for the MCP 2026-07-28 specification
+revision. See the migration guides for upgrading from v1
+(`docs/migration/upgrade-to-v2.md`) and adopting the 2026-07-28 revision
+(`docs/migration/support-2026-07-28.md`).

.changeset/pre.json

@@ -1,28 +1,28 @@
 {
   "mode": "pre",
-  "tag": "alpha",
+  "tag": "beta",
   "initialVersions": {
     "@modelcontextprotocol/eslint-config": "2.0.0",
     "@modelcontextprotocol/tsconfig": "2.0.0",
     "@modelcontextprotocol/vitest-config": "2.0.0",
     "@modelcontextprotocol/examples": "2.0.0-alpha.0",
-    "@modelcontextprotocol/client": "2.0.0-alpha.0",
-    "@modelcontextprotocol/core-internal": "2.0.0-alpha.0",
-    "@modelcontextprotocol/express": "2.0.0-alpha.0",
-    "@modelcontextprotocol/fastify": "2.0.0-alpha.0",
-    "@modelcontextprotocol/hono": "2.0.0-alpha.0",
-    "@modelcontextprotocol/node": "2.0.0-alpha.0",
-    "@modelcontextprotocol/server": "2.0.0-alpha.0",
-    "@modelcontextprotocol/server-legacy": "2.0.0-alpha.0",
-    "@modelcontextprotocol/core": "2.0.0-alpha.0",
-    "@modelcontextprotocol/codemod": "2.0.0-alpha.0",
-    "@modelcontextprotocol/test-conformance": "2.0.0-alpha.0",
-    "@modelcontextprotocol/test-helpers": "2.0.0-alpha.0",
-    "@modelcontextprotocol/test-integration": "2.0.0-alpha.0",
-    "@modelcontextprotocol/test-e2e": "2.0.0-alpha.0",
     "@mcp-examples/client-quickstart": "2.0.0-alpha.0",
     "@mcp-examples/server-quickstart": "2.0.0-alpha.0",
-    "@mcp-examples/shared": "2.0.0-alpha.0"
+    "@mcp-examples/shared": "2.0.0-alpha.0",
+    "@modelcontextprotocol/client": "2.0.0-alpha.4",
+    "@modelcontextprotocol/codemod": "2.0.0-alpha.2",
+    "@modelcontextprotocol/core": "2.0.0-alpha.2",
+    "@modelcontextprotocol/core-internal": "2.0.0-alpha.3",
+    "@modelcontextprotocol/express": "2.0.0-alpha.4",
+    "@modelcontextprotocol/fastify": "2.0.0-alpha.4",
+    "@modelcontextprotocol/hono": "2.0.0-alpha.4",
+    "@modelcontextprotocol/node": "2.0.0-alpha.4",
+    "@modelcontextprotocol/server": "2.0.0-alpha.4",
+    "@modelcontextprotocol/server-legacy": "2.0.0-alpha.4",
+    "@modelcontextprotocol/test-conformance": "2.0.0-alpha.1",
+    "@modelcontextprotocol/test-e2e": "2.0.0-alpha.1",
+    "@modelcontextprotocol/test-helpers": "2.0.0-alpha.0",
+    "@modelcontextprotocol/test-integration": "2.0.0-alpha.1"
   },
   "changesets": [
     "abort-handlers-on-close",

docs/migration/index.md

@@ -19,7 +19,7 @@ v2 packages (`@modelcontextprotocol/client`, `@modelcontextprotocol/server`, …
 Start by running the codemod:
 
 ```bash
-npx @modelcontextprotocol/codemod@alpha v1-to-v2 .
+npx @modelcontextprotocol/codemod@beta v1-to-v2 .
 ```
 
 Run it at the package root (`.`) — real projects import the SDK from `test/`,

docs/migration/support-2026-07-28.md

@@ -614,9 +614,10 @@ Task methods are excluded from the typed method maps: `RequestMethod` / `Request
 `ctx.mcpReq.send()`, `setRequestHandler()`, `setNotificationHandler()` reject task
 methods at compile time. `ResultTypeMap['tools/call']` is plain `CallToolResult` (no
 `| CreateTaskResult`); same for `sampling/createMessage` and `elicitation/create`.
-(The published `2.0.0-alpha.3` typings predate this exclusion — there the typed maps
-still carry the `tasks/*` entries and the `CreateTaskResult` unions; narrow with the
-`isCallToolResult` guard until the next published alpha.) Where
+(Typings published before `2.0.0-alpha.4` predate this exclusion: there the typed
+maps still carry the `tasks/*` entries and the `CreateTaskResult` unions; narrow with
+the `isCallToolResult` guard if you are pinned to one of those alphas. `2.0.0-alpha.4`
+and later include the exclusion.) Where
 task interop is genuinely required, use the explicit-schema custom-method form
 (`request({ method: 'tasks/get', params }, GetTaskResultSchema)`). Inbound `tasks/*`
 requests → `-32601`.

docs/migration/upgrade-to-v2.md

@@ -19,7 +19,7 @@ If you are already on v2 and want to adopt the **2026-07-28 protocol revision**,
    only; CommonJS callers must use dynamic `import()`.
 2. **Run the codemod.**
     ```bash
-    npx @modelcontextprotocol/codemod@alpha v1-to-v2 .
+    npx @modelcontextprotocol/codemod@beta v1-to-v2 .
     ```
     Run it at the **package root** (`.`), not `./src` — it also rewrites `package.json`,
     and real projects import the SDK from `test/`, `scripts/`, and fixtures too.
@@ -233,15 +233,14 @@ for the literal instead; and the emitted quote style differs from v1, so a
 quote-anchored pattern misses silently — match either quote. v2 also ships ESM only:
 `/dist/cjs/` ↔ `/dist/esm/` flavor-pair path swaps have no equivalent.
 
-#### Registry availability during the alpha
+#### Registry availability during the beta
 
-All v2 packages are published on the public npm registry. Two notes for the alpha
+All v2 packages are published on the public npm registry. Two notes for the beta
 window:
 
-- The packages do not share one version number — at the time of writing
-  `@modelcontextprotocol/core` rides a lower prerelease than its siblings. The
-  codemod writes ranges that match what is published, so prefer its manifest output
-  over hand-pinning every package to the same tag.
+- As of `2.0.0-beta.1` all v2 packages share one version number (earlier alphas
+  did not). The codemod writes ranges that match what is published, so prefer its
+  manifest output over hand-pinning every package.
 - Environments that resolve through a corporate or private registry mirror may not
   have synced the newer scoped packages yet (the symptom is "not found" for a package
   that exists on npmjs.org). Point the install at the public registry
@@ -1000,8 +999,9 @@ the third argument — `new SdkHttpError(SdkErrorCode.ClientHttpNotImplemented,
 (carries `data.requiredCapabilities`) are new typed `ProtocolError` subclasses.
 `resources/read` for an unknown URI now answers `-32602` on every protocol revision
 (v1.x already emitted `-32602`; an interim `-32002` from earlier v2 alphas is mapped at
-the encode seam — published `2.0.0-alpha.3` predates the mapping and still emits
-`-32002` on the wire, so accept both until the next published alpha). The encode-seam mapping applies to **your own throws too**: a handler
+the encode seam — `2.0.0-alpha.3` and earlier predate the mapping and still emit
+`-32002` on the wire, so accept both if peers may run those alphas; `2.0.0-alpha.4`
+and later emit `-32602`). The encode-seam mapping applies to **your own throws too**: a handler
 that deliberately throws `ProtocolError(ProtocolErrorCode.ResourceNotFound, …)` reaches
 peers as `-32602` — a server can no longer emit `-32002` on the wire.
 `ProtocolErrorCode.ResourceNotFound` (`-32002`) stays importable as
@@ -1373,12 +1373,12 @@ The role-aggregate unions (`ClientRequest`, `ServerResult`, `ServerRequest`,
 (`RequestMethod`, `RequestTypeMap`, `ResultTypeMap`, `NotificationTypeMap`) no longer
 include task vocabulary; the deprecated `Task*` types remain importable on their own.
 (One published-alpha qualification, like the `-32002` note in [Errors](#errors): the
-`2.0.0-alpha.3` typings predate this — the typed maps there still carry the `tasks/*`
-entries, and `ResultTypeMap['tools/call']` still unions `CreateTaskResult`, so a
-`client.request({ method: 'tools/call', … })` result does not assign to
-`Promise<CallToolResult>`. Narrow with the `isCallToolResult` guard until the next
-published alpha — the guard is the recommended discrimination tool anyway, per the next
-paragraph.)
+`2.0.0-alpha.3` and earlier typings predate this — the typed maps there still carry the
+`tasks/*` entries, and `ResultTypeMap['tools/call']` still unions `CreateTaskResult`, so
+a `client.request({ method: 'tools/call', … })` result does not assign to
+`Promise<CallToolResult>`. If pinned to those alphas, narrow with the
+`isCallToolResult` guard — the recommended discrimination tool anyway, per the next
+paragraph; `2.0.0-alpha.4` and later are unaffected.)
 
 **Discriminating result shapes: use guards, not the `in` operator.** The v2
 zod-inferred result types are passthrough objects — every union member carries an index

examples/client-quickstart/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@mcp-examples/client-quickstart",
     "private": true,
-    "version": "2.0.0-alpha.0",
+    "version": "2.0.0-beta.0",
     "type": "module",
     "scripts": {
         "build": "tsc",

examples/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/examples",
     "private": true,
-    "version": "2.0.0-alpha.0",
+    "version": "2.0.0-beta.0",
     "description": "Runnable MCP TypeScript SDK examples — one story per directory, each a self-verifying client/server pair",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

examples/server-quickstart/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@mcp-examples/server-quickstart",
     "private": true,
-    "version": "2.0.0-alpha.0",
+    "version": "2.0.0-beta.0",
     "type": "module",
     "scripts": {
         "build": "tsc",

examples/shared/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@mcp-examples/shared",
     "private": true,
-    "version": "2.0.0-alpha.0",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/client/README.md

@@ -4,7 +4,7 @@ The MCP (Model Context Protocol) TypeScript client SDK. Build MCP clients that c
 
 <!-- prettier-ignore -->
 > [!WARNING]
-> **This is an alpha release.** Expect breaking changes until v2 stabilizes. We're publishing early to gather feedback — please try it and open issues — but we can't guarantee API stability yet. We'll aim to minimize disruption between alphas.
+> **This is a beta release.** The API surface is settling but breaking changes remain possible until v2 stabilizes. Please try it and open issues — feedback during the beta directly shapes the stable release.
 
 <!-- prettier-ignore -->
 > [!NOTE]
@@ -13,7 +13,7 @@ The MCP (Model Context Protocol) TypeScript client SDK. Build MCP clients that c
 ## Install
 
 ```bash
-npm install @modelcontextprotocol/client@alpha
+npm install @modelcontextprotocol/client@beta
 ```
 
 TypeScript ≥6.0 no longer auto-includes `@types/*` — add `"types": ["node"]` to your `tsconfig.json` `compilerOptions` (the published `.d.mts` references `Buffer`).

packages/client/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@modelcontextprotocol/client",
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript - Client package",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/codemod/README.md

@@ -5,10 +5,10 @@ Codemods for migrating MCP TypeScript SDK code between major versions.
 ## Usage
 
 ```bash
-npx @modelcontextprotocol/codemod@alpha v1-to-v2 .
+npx @modelcontextprotocol/codemod@beta v1-to-v2 .
 
 # or a single source file (manifest changes are reported, not applied)
-npx @modelcontextprotocol/codemod@alpha v1-to-v2 src/server.ts
+npx @modelcontextprotocol/codemod@beta v1-to-v2 src/server.ts
 ```
 
 The codemod rewrites TypeScript and JavaScript source files

packages/codemod/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@modelcontextprotocol/codemod",
-    "version": "2.0.0-alpha.2",
+    "version": "2.0.0-beta.0",
     "description": "Codemod to migrate MCP TypeScript SDK code from v1 to v2",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/core-internal/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/core-internal",
     "private": true,
-    "version": "2.0.0-alpha.3",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript - Core package",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/core/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@modelcontextprotocol/core",
-    "version": "2.0.0-alpha.2",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol for TypeScript — public Zod schemas (spec + OAuth/OpenID)",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/middleware/express/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/express",
     "private": false,
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Express adapters for the Model Context Protocol TypeScript server SDK - Express middleware",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/middleware/fastify/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/fastify",
     "private": false,
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Fastify adapters for the Model Context Protocol TypeScript server SDK - Fastify middleware",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/middleware/hono/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/hono",
     "private": false,
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Hono adapters for the Model Context Protocol TypeScript server SDK - Hono middleware",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/middleware/node/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@modelcontextprotocol/node",
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript - Node.js middleware",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

packages/server-legacy/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/server-legacy",
     "private": false,
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Frozen v1 SSE transport and OAuth Authorization Server helpers for the Model Context Protocol TypeScript SDK. Deprecated; use StreamableHTTP and a dedicated OAuth server in production.",
     "deprecated": "This package is a frozen copy of v1's SSE transport and OAuth Authorization Server helpers for migration purposes only. Use StreamableHTTP from @modelcontextprotocol/server and a dedicated OAuth server in production. Will not receive new features.",
     "license": "MIT",

packages/server/README.md

@@ -4,7 +4,7 @@ The MCP (Model Context Protocol) TypeScript server SDK. Build MCP servers that e
 
 <!-- prettier-ignore -->
 > [!WARNING]
-> **This is an alpha release.** Expect breaking changes until v2 stabilizes. We're publishing early to gather feedback — please try it and open issues — but we can't guarantee API stability yet. We'll aim to minimize disruption between alphas.
+> **This is a beta release.** The API surface is settling but breaking changes remain possible until v2 stabilizes. Please try it and open issues — feedback during the beta directly shapes the stable release.
 
 <!-- prettier-ignore -->
 > [!NOTE]
@@ -13,7 +13,7 @@ The MCP (Model Context Protocol) TypeScript server SDK. Build MCP servers that e
 ## Install
 
 ```bash
-npm install @modelcontextprotocol/server@alpha
+npm install @modelcontextprotocol/server@beta
 ```
 
 TypeScript ≥6.0 no longer auto-includes `@types/*` — add `"types": ["node"]` to your `tsconfig.json` `compilerOptions` (the published `.d.mts` references `Buffer`).

packages/server/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@modelcontextprotocol/server",
-    "version": "2.0.0-alpha.4",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript - Server package",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

test/conformance/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/test-conformance",
     "private": true,
-    "version": "2.0.0-alpha.1",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

test/e2e/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/test-e2e",
     "private": true,
-    "version": "2.0.0-alpha.1",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

test/helpers/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/test-helpers",
     "private": true,
-    "version": "2.0.0-alpha.0",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",

test/integration/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@modelcontextprotocol/test-integration",
     "private": true,
-    "version": "2.0.0-alpha.1",
+    "version": "2.0.0-beta.0",
     "description": "Model Context Protocol implementation for TypeScript",
     "license": "MIT",
     "author": "Anthropic, PBC (https://anthropic.com)",