MCP Server integration

[NoaJunod]

Integrate the Model Context Protocol using Spring AI to offer the validator as tool for LLMs.
https://docs.spring.io/spring-ai/reference/index.html

[oliveregger]

we get sometimes errors on matchbox test instance

Error from MCP server: SseError: SSE error: TypeError: terminated: other side closed
at _eventSource.onerror (file:///opt/homebrew/lib/node_modules/@modelcontextprotocol/inspector/node_modules/@modelcontextprotocol/sdk/dist/esm/client/sse.js:69:31)
at EventSource.scheduleReconnect_fn (file:///opt/homebrew/lib/node_modules/@modelcontextprotocol/inspector/node_modules/eventsource/dist/index.js:248:53)
at file:///opt/homebrew/lib/node_modules/@modelcontextprotocol/inspector/node_modules/eventsource/dist/index.js:98:174
at process.processTicksAndRejections (node:internal/process/task_queues:105:5) {
code: undefined,
event: {
type: 'error',
message: 'TypeError: terminated: other side closed',
code: undefined,
defaultPrevented: false,
cancelable: false,
timeStamp: 2069962.487041
}
}

[oliveregger]

2025-06-16 13:00:03.278 INFO [nio-8080-exec-4] i.m.server.McpAsyncServer :197: Client initialize request - Protocol: 2025-03-26, Capabilities: ClientCapabilities[experimental=null, roots=RootCapabilities[listChanged=true], sampling=Sampling[]], Info: Implementation[name=mcp-inspector, version=0.12.0]
2025-06-16 13:00:03.280 WARN [nio-8080-exec-4] i.m.server.McpAsyncServer :213: Client requested unsupported protocol version: 2025-03-26, so the server will suggest the 2024-11-05 version instead
2025-06-16 13:00:05.296 INFO [nio-8080-exec-6] .coyote.http11.Http11Processor:175: Error parsing HTTP request header
Note: further occurrences of HTTP request parsing errors will be logged at DEBUG level.
java.lang.IllegalArgumentException: Invalid character found in method name [0x160x030x010x01v0x010x000x01r0x030x030xddf0x02 ]. HTTP method names must be tokens
at java.base/java.lang.Thread.run(Thread.java:1583) [9 skipped]

[oliveregger]

should / can we update to
spring-ai-starter-mcp-server-webflux

see spring-projects/spring-ai#3301

[NoaJunod]

webflux also uses protocol version 2024-11-05

[oliveregger]

see also discussion in
https://www.alibabacloud.com/blog/602197

[oliveregger]

seem we are bit too early: modelcontextprotocol/java-sdk#290

[ZachGerman]

Was on-call last week (had no time for MCP contribution), but I'm back at it this week. I should be able to finish modelcontextprotocol/java-sdk#290 before the week is over.

[ZachGerman]

Update on the above: What's in there now should work, but no sessionless or GET-style initialization (initializeRequests must go to POST according to spec)

[qligier]

@ZachGerman Thank you for the update here – greatly appreciated – and for your work on the implementation!