---
title: "@modelcontextprotocol/sdk (npm) Breaking Changes | Since.dev"
description: "What each @modelcontextprotocol/sdk release removed, renamed or changed: 118 breaking changes in 14 versions on npm, each with its source."
canonical_url: https://since.dev/packages/npm/@modelcontextprotocol/sdk
last_updated: 2026-10-02
---

# @modelcontextprotocol/sdk breaking changes

Every breaking API change we have recorded in @modelcontextprotocol/sdk on npm: 118 breaking changes in 14 versions. Below are its newest 6 versions, removals and renames first, each with its source.

Newest change October 2, 2026

## 1.32.0

9 breaking changes, first published October 2, 2026.

- **Behavior changed**  

Tasks in the in-memory task store are now kept within the session that created them, so code that reads tasks across sessions will no longer see them. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.32.0)
- **Behavior changed** `SSEClientTransport`  

A redirect to another host or port is no longer followed. Configure the final URL or set redirectPolicy to 'follow' on the transport; in browsers the request fails unless that option is set. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.32.0)
- **Behavior changed** `StreamableHTTPClientTransport`  

A redirect to another host or port is no longer followed. Configure the final URL or set redirectPolicy to 'follow' on the transport; in browsers the request fails unless that option is set. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.createTask`  

Was createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: Request, \_sessionId?: string): Promise<Task>; now createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: Request, sessionId?: string)... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.getTask`  

Was getTask(taskId: string, \_sessionId?: string): Promise<Task | null>; now getTask(taskId: string, sessionId?: string): Promise<Task | null>. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.getTaskResult`  

Was getTaskResult(taskId: string, \_sessionId?: string): Promise<Result>; now getTaskResult(taskId: string, sessionId?: string): Promise<Result>. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.listTasks`  

Was listTasks(cursor?: string, \_sessionId?: string): Promise<{tasks: Task\[\]; nextCursor?: string;}>; now listTasks(cursor?: string, sessionId?: string): Promise<{tasks: Task\[\]; nextCursor?: string;}>. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.storeTaskResult`  

Was storeTaskResult(taskId: string, status: 'completed' | 'failed', result: Result, \_sessionId?: string): Promise<void>; now storeTaskResult(taskId: string, status: 'completed' | 'failed', result: Result, sessionId?: string): Promise<void>. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)
- **Signature changed** `experimental:InMemoryTaskStore.updateTaskStatus`  

Was updateTaskStatus(taskId: string, status: Task\['status'\], statusMessage?: string, \_sessionId?: string): Promise<void>; now updateTaskStatus(taskId: string, status: Task\['status'\], statusMessage?: string, sessionId?: string)... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.32.0)

## 1.31.0

1 breaking change, first published September 28, 2026.

- **Behavior changed**  

Stored OAuth tokens and client information now include an issuer field. Storage that rejects unknown fields must be changed to allow it. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.31.0)

## 1.30.0

1 breaking change, first published July 27, 2026.

- **Behavior changed**  

The v1 stdio transport now applies a buffer size limit, so very large messages may be rejected. Check that your messages stay within the limit. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.30.0)

## 1.29.0

7 breaking changes, first published March 30, 2026.

- **Behavior changed**  

Requests that pass a null (infinite) TTL are now disallowed, so callers must send a finite TTL value instead. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v1.29.0)
- **Signature changed** `client:Client.callTool`  

Was callTool(params: CallToolRequest\['params'\], resultSchema?: typeof CallToolResultSchema | typeof CompatibilityCallToolResultSchema, options?: RequestOptions): Promise<{\[x: string\]: unknown; content: ({type: "text"; text: string... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)
- **Signature changed** `client:Client.getPrompt`  

Was getPrompt(params: GetPromptRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; messages: {role: "user" | "assistant"; content: {type: "text"; text: string; annotations?: {audience?: ("user" | "assistant")\[\] |... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)
- **Signature changed** `client:Client.listResources`  

Was listResources(params?: ListResourcesRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; resources: {uri: string; name: string; description?: string | undefined; mimeType?: string | undefined; annotations?... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)
- **Signature changed** `experimental:CreateTaskRequestHandlerExtra.taskRequestedTtl`  

Was taskRequestedTtl?: number | null; now taskRequestedTtl?: number. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)
- **Signature changed** `experimental:TaskCreationParamsSchema`  

Was const TaskCreationParamsSchema: z.ZodObject<{ttl: z.ZodOptional<z.ZodUnion<readonly \[z.ZodNumber, z.ZodNull\]>>; pollInterval: z.ZodOptional<z.ZodNumber>;}, z.core.$loose>; now const TaskCreationParamsSchema: z.ZodObject<{ttl... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)
- **Signature changed** `experimental:TaskRequestHandlerExtra.taskRequestedTtl`  

Was taskRequestedTtl?: number | null; now taskRequestedTtl?: number. [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.29.0)

## 1.28.0

3 breaking changes, first published March 25, 2026.

- **Behavior changed**  

The SDK now uses scopes_supported from resource metadata by default, so authorization requests may request different scopes than before. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v1.28.0)
- **Behavior changed** `inputSchema`  

Passing a plain JSON Schema object as inputSchema is now rejected, so code using that form must switch to a supported schema type. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v1.28.0)
- **Default changed**  

When a server omits token_endpoint_auth_methods_supported, the client now defaults to client_secret_basic authentication. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v1.28.0)

## 1.25.0

33 breaking changes, first published December 15, 2025.

- **Removed**  

Loose and passthrough types not allowed by the MCP spec were removed, so code that depended on them may no longer type-check. Update code to use the spec-defined types. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.25.0)
- **Behavior changed**  

Protocol dates are now validated, so date values that were previously accepted may be rejected. [github.com](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.25.0)
- **Signature changed** `client:Client.callTool`  

Was callTool(params: CallToolRequest\['params'\], resultSchema?: typeof CallToolResultSchema | typeof CompatibilityCallToolResultSchema, options?: RequestOptions): Promise<{\[x: string\]: unknown; content: ({type: "text"; text: string... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.complete`  

Was complete(params: CompleteRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; completion: {\[x: string\]: unknown; values: string\[\]; total?: number | undefined; hasMore?: boolean | undefined;}; \_meta?: {\[x... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.getPrompt`  

Was getPrompt(params: GetPromptRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; messages: {role: "user" | "assistant"; content: {type: "text"; text: string; annotations?: {audience?: ("user" | "assistant")\[\] |... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.listPrompts`  

Was listPrompts(params?: ListPromptsRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; prompts: {name: string; description?: string | undefined; arguments?: {name: string; description?: string | undefined... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.listResources`  

Was listResources(params?: ListResourcesRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; resources: {uri: string; name: string; description?: string | undefined; mimeType?: string | undefined; annotations?... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.listResourceTemplates`  

Was listResourceTemplates(params?: ListResourceTemplatesRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; resourceTemplates: {uriTemplate: string; name: string; description?: string | undefined; mimeType?: string... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.listTools`  

Was listTools(params?: ListToolsRequest\['params'\], options?: RequestOptions): Promise<{\[x: string\]: unknown; tools: {inputSchema: {\[x: string\]: unknown; type: "object"; properties?: Record<string, object> | undefined; required?: string\[\] |... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)
- **Signature changed** `client:Client.ping`  

Was ping(options?: RequestOptions): Promise<{\_meta?: {\[x: string\]: unknown; "io.modelcontextprotocol/related-task"?: {\[x: string\]: unknown; taskId: string;} | undefined;} | undefined;}>; now ping(options?: RequestOptions): Promise<{\_meta?... [npmjs.com](https://www.npmjs.com/package/@modelcontextprotocol/sdk/v/1.25.0)

And 23 more in this version.

## Check your code

These are the changes. To see which of them reach your code, [scan a public repository](https://since.dev/scan.md), or have your coding agent call `check_code` with your manifest or lockfile over [MCP](https://since.dev/docs.md#mcp). [The API](https://since.dev/docs.md#api) reads every change in every version, not only the newest. On Team and up, a fix pull request opens for the changes that reach a connected repository. Nothing merges or deploys.

## Put your code on continuous management.

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