Merge branch 'main' into fweinberger/v2-bc-register-rawshape

Author: felixweinberger

.changeset/export-inmemory-transport.md

@@ -0,0 +1,6 @@
+---
+'@modelcontextprotocol/server': patch
+'@modelcontextprotocol/client': patch
+---
+
+Export `InMemoryTransport` for in-process testing.

docs/migration.md

@@ -469,22 +469,20 @@ const client = new Client(
 );
 ```
 
-### `InMemoryTransport` removed from public API
+### `InMemoryTransport` moved
 
-`InMemoryTransport` has been removed from the public API surface. It was previously used for in-process client-server connections and testing.
-
-For **testing**, import it directly from the internal core package:
+`InMemoryTransport` is now exported from `@modelcontextprotocol/client` and `@modelcontextprotocol/server` (both re-export it). It is still intended for in-process client-server connections and testing.
 
 ```typescript
 // v1
 import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js';
 
-// v2 (testing only — @modelcontextprotocol/core is internal, not for production use)
-import { InMemoryTransport } from '@modelcontextprotocol/core';
+// v2
+import { InMemoryTransport } from '@modelcontextprotocol/server';
+// or
+import { InMemoryTransport } from '@modelcontextprotocol/client';
 ```
 
-For **production in-process connections**, use `StreamableHTTPClientTransport` with a local server URL, or connect client and server via paired streams.
-
 ### Removed type aliases and deprecated exports
 
 The following deprecated type aliases have been removed from `@modelcontextprotocol/core`:

packages/core/src/exports/public/index.ts

@@ -70,6 +70,7 @@ export { deserializeMessage, ReadBuffer, serializeMessage } from '../../shared/s
 // Transport types (NOT normalizeHeaders)
 export type { FetchLike, Transport, TransportSendOptions } from '../../shared/transport.js';
 export { createFetchWithInit } from '../../shared/transport.js';
+export { InMemoryTransport } from '../../util/inMemory.js';
 
 // URI Template
 export type { Variables } from '../../shared/uriTemplate.js';

packages/core/src/util/inMemory.ts

@@ -9,6 +9,9 @@ interface QueuedMessage {
 
 /**
  * In-memory transport for creating clients and servers that talk to each other within the same process.
+ *
+ * Intended for testing and development. For production in-process connections, use
+ * `StreamableHTTPClientTransport` against a local server URL.
  */
 export class InMemoryTransport implements Transport {
     private _otherTransport?: InMemoryTransport;