SHOULD Send with 'application/json' content-type in notifications responses

[YifengWong]

typescript-sdk/packages/server/src/server/webStandardStreamableHttp.ts

Line 670 in 6b4d99f

return new Response(null, { status: 202 });

In notifications responses, there is only the status code 202, but without content-type application/json. It would make my java client requests error, because the java client checks EVERY response with application/json content-type

[YifengWong]

Java client codes in io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport

[mattzcarey]

Reopening this since it should be fixed on the Java client. I don't play with Java too much but it seems like it may have been fixed in. modelcontextprotocol/java-sdk#589

Or there is a similar issue open here modelcontextprotocol/java-sdk#396

[felixweinberger]

this is actually expected behavior per the spec — the server MUST return HTTP status code 202 Accepted with no body for notifications, so setting Content-Type: application/json would be semantically wrong.

the fix should be on the java client side, which looks like it's been addressed in modelcontextprotocol/java-sdk#589. can you confirm if that fixes things for you?