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MCP Connector

Anypoint Connector for MCP (MCP Connector) uses the Model Context Protocol (MCP) to enable AI clients that support MCP to invoke and interact with APIs, connectors, and apps.

Guide: MCP Connector User Guide

1.7.0

August 25, 2026

What’s New

  • The MCP Java SDK is upgraded from 1.0.1 to 2.0.0. Connector operations, sources, configuration, and error types are unchanged.

  • The MCP SDK’s JSON provider is migrated to Jackson 3. Connector operations, sources, configuration, and error types are unchanged.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

2.0.0

MCP Protocol

2025-06-18

Fixed Issues

Issue Resolution ID

The Streamable HTTP transport no longer leaks resources by holding open a persistent Server-Sent Events (SSE) stream for every non-initialize request. Response framing is now deferred until an outbound message is actually sent: non-eliciting requests (such as tools/call, resources/read, and prompts/get) return a plain application/json response, and an SSE stream is opened only when the server must send a server-initiated message such as an elicitation.

As part of the Streamable HTTP framing change, a request that triggers a server-initiated message (an elicitation) now requires the client to advertise the SSE channel in its Accept header. Clients that call such operations must send:

Accept: application/json, text/event-stream

A client that sends only Accept: application/json and then triggers an elicitation receives an INVALID_REQUEST error. Spec-conformant MCP clients already send both media types and are unaffected. If you maintain a custom MCP client, ensure it advertises text/event-stream on requests that might elicit.

W-23293249

1.6.1

July 17, 2026

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

1.0.1

MCP Protocol

2025-06-18

Fixed Issues

Issue Resolution ID

Session has not been initialized and Response was already initiated errors no longer occur with strict MCP clients that omit the session ID on the request following the initialize response.

W-23239922

The MCP server no longer accumulates a gradual memory leak in long-running server deployments.

W-22555872

The Jackson dependencies are upgraded to 2.22.1 to address security vulnerabilities.

W-3300013

1.6.0

June 8, 2026

What’s New

  • MCP Connector now includes the MCP Server - Create Elicitation operation and the MCP Client - Elicitation Listener source.

    These capabilities implement the MCP elicitation protocol so servers can request additional structured input from clients during tool and resource execution.

  • Elicitation is opt-in through the new Enable Elicitations field on the client configuration.

    For multi-worker deployments, use Streamable HTTP server transport and configure an Object Store on the server connection so elicitation correlation is preserved across workers. SSE server transport is single-worker only.

  • Server connection configuration now includes the new Elicitation Timeout Seconds, Elicitations Object Store, and Elicitation Polling Seconds fields to route elicitation responses across replicas.

  • The MCP Client - List Tools, MCP Client - List Resources, and MCP Client - List Prompts operations now include the new Additional Properties field.

    Pass custom headers, correlation IDs, tenant identifiers, or other metadata on list calls. The values are propagated to the corresponding server-side listeners and are accessible from attributes.additionalProperties.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

1.0.1

MCP Protocol

2025-06-18

Fixed Issues

Issue Resolution ID

The MCP client now refreshes the OAuth bearer token automatically when an outbound request receives an HTTP 401 response, and the resulting error is reclassified as a connectivity error so it is eligible for reconnection.

W-22677666

Events emitted by the MCP Server - On New Session Listener source are no longer counted toward Usage-Based Pricing metering. The source fires as a byproduct of the upstream HTTP listener trigger, so its events were being double-counted.

W-21663653

1.5.0

May 1, 2026

What’s New

  • MCP Connector now includes the MCP Client - Get Prompt and MCP Client - List Prompts operations, and the MCP Server - Prompt Listener source.

    Expose server-side prompt templates with typed arguments and consume them from clients, with responses supporting text, image, embedded resource, and resource link content.

  • The MCP Client - Call Tool operation now includes the new Extract Structured Content field.

    Define tool parameter and output schemas using either inline JSON or external files, fully supported by robust design-time schema validation. With this, the connector now also includes the new MCP:SCHEMA_VALIDATION_FAILED error.

  • The connector now includes response attributes to support structured client-side error handling with HTTP response details. With this, the connector now also includes the new MCP:UNAUTHORIZED error.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

1.0.1

MCP Protocol

2025-06-18

1.4.0

March 22, 2026

What’s New

  • The MCP Java SDK is upgraded to the latest release version (1.0.0).

  • Both the server and client transports now default to 2025-06-18 as the preferred version of the protocol.

  • Both the server and client transports now set the Mcp-Protocol-Version header to the version negotiated upon connection initialization.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

1.0.0

MCP Protocol

2025-06-18

Fixed Issues

Issue Resolution ID

When no audience is defined in the Mule flow, TextContent responses for tool calls no longer serialize an empty audience array in annotations. An empty array could cause some MCP clients to interpret the content as being visible to nobody and filter it out.

W-21425262

1.3.1

January 16, 2026

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.11.2

Fixed Issues

Issue Resolution ID

Nested objects are now properly serialized for downstream consumption.

W-20405721

In the MCP Server - On New Session Listener source, a NullPointerException error no longer occurs in the response builder when the header isn’t defined.

W-20437648

Tool parameters are now validated according to the JSON schema before execution.

W-20037056

1.3.0

November 13, 2025

What’s New

  • The MCP Server - On New Session Listener source now supports custom rejection headers with the new Reject With Headers field.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.11.2

Fixed Issues

Issue Resolution ID

In the MCP Server - On New Session Listener source, the Reject With Status Code field now correctly returns custom rejection status codes instead of defaulting to 500.

W-19387519

The connector now properly cleans up tracked inbound requests even when exceptions occur during message processing, preventing memory leaks that could accumulate over time.

W-20037035

1.2.1

September 11, 2025

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.11.2

Fixed Issues

Issue Resolution ID

The MCP server now responds with HTTP 404 for expired sessions, and the MCP client now properly handles session expiration by creating a new session when receiving HTTP 404 responses.

W-19178802

Connection and disconnection handling is now improved because disconnect methods are now properly subscribed and executed.

W-19264682

1.2.0

August 6, 2025

What’s New

  • MCP Connector now supports distributed tracing.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.10.0

1.1.0

July 18, 2025

What’s New

  • A Default Request Headers parameter is added to both the SSE Client and Streamable HTTP Client connection types within the MCP Connector’s Client configuration. This parameter lets you specify custom headers to send with every request to the MCP server.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.10.0

Fixed Issues

Issue Resolution ID

Serialization errors with ObjectStore v2 no longer occur.

W-19045311

1.0.0

June 26, 2025

What’s New

  • MCP Connector 1.0.0 is not backward-compatible with the 0.1.0-BETA version of this connector. For more information, see Upgrading MCP Connector to Version 1.0.0.

  • Support for the Streamable HTTP transport method is added.

  • You can now add custom response headers on every exposed endpoint (including /sse, /messages, and the new /mcp).

  • You no longer need to add the mule.http.service.implementation=NETTY system property.

Compatibility

Software Version

Mule

4.9.6 and later

OpenJDK

17

MCP Java SDK

0.10.0

0.1.0-BETA (Deprecated)

April 15, 2025

What’s New

This is a new connector.

MCP Connector is a beta connector that is subject to the Beta Services Terms at Agreements - Salesforce.com or a written Unified Pilot Agreement if executed by Customer, and the Non-GA Gen AI and Non-GA Credit Consumption terms in the Product Terms Directory. Use of this beta connector with external systems or services consumes Mule messages and is at the Customer’s sole discretion.

For more information, see the MCP Connector User Guide.

Compatibility

Software Version

Mule

4.9.3 and later

OpenJDK

17

See Also