Add support for MCP protocol revision 2026-07-28, including server/discover and the updated stateless lifecycle, to improve interoperability with modern MCP clients, particularly ChatGPT Business.

Context

We use the XWiki MCP Server (xwiki-contrib/ai-llm) to integrate our organization's XWiki knowledge base with AI agents through ChatGPT Business.

During our initial integration using version 0.9, we encountered a protocol compatibility issue that prevented the client from discovering the MCP tools.

Our subsequent source-code review indicates that versions 0.9 and 0.10 depend on MCP Java SDK 2.0.0, while the current development branch (0.10.1-SNAPSHOT) depends on SDK 2.0.1. These SDK versions do not appear to provide native support for the MCP 2026-07-28 lifecycle.

Observed behavior

The ChatGPT MCP client attempted to invoke server/discover, introduced in protocol revision 2026-07-28.

However, the XWiki MCP Server did not recognize this method through the underlying Java SDK.

The same behavior has been documented upstream, where MCP Java SDK 2.0.0 may return HTTP 500 with an error similar to:

Missing handler for request type: server/discover

As a temporary workaround, we implemented a compatibility adaptation in our Traefik reverse proxy to handle the discovery request while forwarding the remaining MCP operations to XWiki.

Following this adaptation and a separate OAuth/OIDC authentication configuration adjustment, the integration became operational.

However, the workaround does not establish full compliance with MCP 2026-07-28.

Requested improvement

We would like to request native support for the latest MCP protocol revision in the XWiki MCP Server, preferably by adopting the corresponding capabilities of the official MCP Java SDK as they become available.

In particular, we suggest considering:

1. Native support for server/discover and the 2026-07-28 stateless lifecycle.

1. Correct protocol version negotiation and capability advertisement.

1. Standards-compliant handling of unsupported methods, including appropriate JSON-RPC errors and HTTP status codes.

1. Backward compatibility with existing MCP clients, where feasible.

1. Preservation of OAuth/OIDC authentication and XWiki's native access-control mechanisms.

1. Interoperability tests with modern MCP clients, including ChatGPT Business.

Expected behavior

A compatible MCP client should be able to discover and invoke the tools exposed by XWiki without requiring custom reverse-proxy adaptations.

When a requested protocol method or version is unsupported, the server should return a standards-compliant response rather than an unexpected internal server error, allowing clients that implement backward-compatibility mechanisms to respond appropriately.

Acceptance criteria

• The server correctly supports server/discover when advertising protocol revision 2026-07-28.

• Modern MCP clients can discover and invoke XWiki tools without a compatibility proxy.

• Unsupported methods receive appropriate protocol-level errors.

• Existing authentication, authorization, and permission checks remain effective.

• Compatibility with legacy MCP clients is preserved where supported.

• Automated interoperability tests cover the supported protocol versions.

Related upstream issues

• MCP Java SDK — Stateless lifecycle support: https://github.com/modelcontextprotocol/java-sdk/issues/1011

• MCP Java SDK — OpenAI server/discover compatibility issue: https://github.com/modelcontextprotocol/java-sdk/issues/1072

• MCP Java SDK — HTTP status handling for unsupported methods: https://github.com/modelcontextprotocol/java-sdk/pull/1083

Additional information

We understand that the implementation may depend on the evolution of the official MCP Java SDK.

We would appreciate the maintainers' assessment of the proposed improvement and whether support for MCP 2026-07-28 is already planned for a future release.

Thank you for maintaining and improving this integration.