Match legacy SSE Cache-Control: no-cache, no-transform

maxisbey · maxisbey · commit 6ac24b7ebfa1 · 2026-06-26T15:33:31.000Z
diff --git a/src/mcp/server/_streamable_http_modern.py b/src/mcp/server/_streamable_http_modern.py
@@ -149,7 +149,7 @@ async def _to_jsonrpc_response(
 
 _SSE_HEADERS: Final[list[tuple[bytes, bytes]]] = [
     (b"content-type", b"text/event-stream"),
-    (b"cache-control", b"no-store"),
+    (b"cache-control", b"no-cache, no-transform"),
     (b"connection", b"keep-alive"),
     (b"x-accel-buffering", b"no"),
 ]

Original file line number	Diff line number	Diff line change
`@@ -149,7 +149,7 @@ async def _to_jsonrpc_response(`
`149`	`149`
`150`	`150`	`_SSE_HEADERS: Final[list[tuple[bytes, bytes]]] = [`
`151`	`151`	`(b"content-type", b"text/event-stream"),`
`152`		`- (b"cache-control", b"no-store"),`
	`152`	`+ (b"cache-control", b"no-cache, no-transform"),`
`153`	`153`	`(b"connection", b"keep-alive"),`
`154`	`154`	`(b"x-accel-buffering", b"no"),`
`155`	`155`	`]`