Merge branch 'main' into fweinberger/elicit-schema-catchall

Author: felixweinberger

.changeset/add-fastify-middleware.md

@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/fastify': minor
+---
+
+Add Fastify middleware adapter for MCP servers, following the same pattern as the Express and Hono adapters.

.changeset/drop-zod-peer-dep.md

@@ -0,0 +1,9 @@
+---
+'@modelcontextprotocol/client': patch
+'@modelcontextprotocol/server': patch
+---
+
+Drop `zod` from `peerDependencies` (kept as direct dependency)
+
+Since Standard Schema support landed, `zod` is purely an internal runtime dependency used for protocol message parsing. User-facing schemas (`registerTool`, `registerPrompt`) accept any Standard Schema library. `zod` remains in `dependencies` and auto-installs; users no longer
+need to install it alongside the SDK.

.changeset/fix-abort-listener-leak.md

@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/core': patch
+---
+
+Consolidate per-request cleanup in `_requestWithSchema` into a single `.finally()` block. This fixes an abort signal listener leak (listeners accumulated when a caller reused one `AbortSignal` across requests) and two cases where `_responseHandlers` entries leaked on send-failure paths.

.changeset/fix-server-protocol-version.md

@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/server': patch
+---
+
+fix(server): propagate negotiated protocol version to transport in _oninitialize

.changeset/fix-streamable-http-error-response.md

@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/client': patch
+---
+
+Fix StreamableHTTPClientTransport to handle error responses in SSE streams

.changeset/pre.json

@@ -0,0 +1,25 @@
+{
+  "mode": "pre",
+  "tag": "alpha",
+  "initialVersions": {
+    "@modelcontextprotocol/eslint-config": "2.0.0",
+    "@modelcontextprotocol/tsconfig": "2.0.0",
+    "@modelcontextprotocol/vitest-config": "2.0.0",
+    "@modelcontextprotocol/examples-client": "2.0.0-alpha.0",
+    "@modelcontextprotocol/examples-client-quickstart": "2.0.0-alpha.0",
+    "@modelcontextprotocol/examples-server": "2.0.0-alpha.0",
+    "@modelcontextprotocol/examples-server-quickstart": "2.0.0-alpha.0",
+    "@modelcontextprotocol/examples-shared": "2.0.0-alpha.0",
+    "@modelcontextprotocol/client": "2.0.0-alpha.0",
+    "@modelcontextprotocol/core": "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/test-conformance": "2.0.0-alpha.0",
+    "@modelcontextprotocol/test-helpers": "2.0.0-alpha.0",
+    "@modelcontextprotocol/test-integration": "2.0.0-alpha.0"
+  },
+  "changesets": []
+}

.github/workflows/main.yml

@@ -4,8 +4,6 @@ on:
             - main
     pull_request:
     workflow_dispatch:
-    release:
-        types: [published]
 
 concurrency:
     group: ${{ github.workflow }}-${{ github.ref }}
@@ -94,53 +92,3 @@ jobs:
             - name: Run ${{ matrix.runtime }} integration tests
               run: pnpm --filter @modelcontextprotocol/test-integration test:integration:${{ matrix.runtime }}
 
-    publish:
-        runs-on: ubuntu-latest
-        if: github.event_name == 'release'
-        environment: release
-        needs: [build, test, test-runtimes]
-
-        permissions:
-            contents: read
-            id-token: write
-
-        steps:
-            - uses: actions/checkout@v6
-
-            - name: Install pnpm
-              uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v5.0.0
-              id: pnpm-install
-              with:
-                  run_install: false
-            - uses: actions/setup-node@v6
-              with:
-                  node-version: 24
-                  cache: pnpm
-                  cache-dependency-path: pnpm-lock.yaml
-                  registry-url: 'https://registry.npmjs.org'
-            - run: pnpm install
-
-            - name: Determine npm tag
-              id: npm-tag
-              run: |
-                  VERSION=$(node -p "require('./package.json').version")
-                  # Check if this is a beta release
-                  if [[ "$VERSION" == *"-beta"* ]]; then
-                    echo "tag=--tag beta" >> $GITHUB_OUTPUT
-                  # Check if this release is from a non-primary branch (patch/maintenance release)
-                  elif [[ "${{ github.event.release.target_commitish }}" != "main" && "${{ github.event.release.target_commitish }}" != "v1.x" ]]; then
-                    # Use "release-X.Y" as tag for old branch releases (e.g., "release-1.23" for 1.23.x)
-                    # npm tags are mutable pointers to versions (like "latest" pointing to 1.24.3).
-                    # Using "release-1.23" means users can `npm install @modelcontextprotocol/sdk@release-1.23`
-                    # to get the latest patch on that minor version, and the tag updates if we
-                    # release 1.23.2, 1.23.3, etc.
-                    # Note: Can't use "v1.23" because npm rejects tags that look like semver ranges.
-                    MAJOR_MINOR=$(echo "$VERSION" | cut -d. -f1,2)
-                    echo "tag=--tag release-${MAJOR_MINOR}" >> $GITHUB_OUTPUT
-                  else
-                    echo "tag=" >> $GITHUB_OUTPUT
-                  fi
-
-            - run: pnpm publish --provenance --access public ${{ steps.npm-tag.outputs.tag }}
-              env:
-                  NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/publish.yml

@@ -40,4 +40,4 @@ jobs:
             - name: Publish preview packages
               run:
                   pnpm dlx pkg-pr-new publish --packageManager=npm --pnpm './packages/server' './packages/client'
-                  './packages/middleware/express' './packages/middleware/hono' './packages/middleware/node'
+                  './packages/middleware/express' './packages/middleware/fastify' './packages/middleware/hono' './packages/middleware/node'

CLAUDE.md

@@ -164,7 +164,7 @@ When a request arrives from the remote side:
 3. **`Protocol._onrequest()`**:
     - Looks up handler in `_requestHandlers` map (keyed by method name)
     - Creates `BaseContext` with `signal`, `sessionId`, `sendNotification`, `sendRequest`, etc.
-    - Calls `buildContext()` to let subclasses enrich the context (e.g., Server adds `requestInfo`)
+    - Calls `buildContext()` to let subclasses enrich the context (e.g., Server adds HTTP request info)
     - Invokes handler, sends JSON-RPC response back via transport
 4. **Handler** was registered via `setRequestHandler('method', handler)`
 

README.md

@@ -39,7 +39,7 @@ This monorepo publishes split packages:
 - **`@modelcontextprotocol/server`**: build MCP servers
 - **`@modelcontextprotocol/client`**: build MCP clients
 
-Both packages have a **required peer dependency** on `zod` for schema validation. The SDK uses Zod v4.
+Tool and prompt schemas use [Standard Schema](https://standardschema.dev/) — bring Zod v4, Valibot, ArkType, or any compatible library.
 
 ### Middleware packages (optional)
 
@@ -56,21 +56,21 @@ They are intentionally thin adapters: they should not introduce new MCP function
 ### Server
 
 ```bash
-npm install @modelcontextprotocol/server zod
+npm install @modelcontextprotocol/server
 # or
-bun add @modelcontextprotocol/server zod
+bun add @modelcontextprotocol/server
 # or
-deno add npm:@modelcontextprotocol/server npm:zod
+deno add npm:@modelcontextprotocol/server
 ```
 
 ### Client
 
 ```bash
-npm install @modelcontextprotocol/client zod
+npm install @modelcontextprotocol/client
 # or
-bun add @modelcontextprotocol/client zod
+bun add @modelcontextprotocol/client
 # or
-deno add npm:@modelcontextprotocol/client npm:zod
+deno add npm:@modelcontextprotocol/client
 ```
 
 ### Optional middleware packages
@@ -157,7 +157,8 @@ The `docs:multi` script checks out both the `v1.x` and `main` branches via git w
 
 ## v1 (legacy) documentation and fixes
 
-If you are using the **v1** generation of the SDK, the **v1 API documentation** is available at [`https://ts.sdk.modelcontextprotocol.io/`](https://ts.sdk.modelcontextprotocol.io/). The v1 source code and any v1-specific fixes live on the long-lived [`v1.x` branch](https://github.com/modelcontextprotocol/typescript-sdk/tree/v1.x). V2 API docs are at [`/v2/`](https://ts.sdk.modelcontextprotocol.io/v2/).
+If you are using the **v1** generation of the SDK, the **v1 API documentation** is available at [`https://ts.sdk.modelcontextprotocol.io/`](https://ts.sdk.modelcontextprotocol.io/). The v1 source code and any v1-specific fixes live on the long-lived
+[`v1.x` branch](https://github.com/modelcontextprotocol/typescript-sdk/tree/v1.x). V2 API docs are at [`/v2/`](https://ts.sdk.modelcontextprotocol.io/v2/).
 
 ## Contributing