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Acknowledge notification POSTs with 202 on the 2026-07-28 HTTP entry (#3326)

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Max 2026-08-17 21:15:35 +01:00 • committed by GitHub
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35
tests/interaction/transports/test_hosting_http_modern.py
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@ -20,6 +20,7 @@ from mcp_types import (
HEADER_MISMATCH,
INTERNAL_ERROR,
INVALID_PARAMS,
INVALID_REQUEST,
METHOD_NOT_FOUND,
MISSING_REQUIRED_CLIENT_CAPABILITY,
SERVER_INFO_META_KEY,
@ -27,6 +28,7 @@ from mcp_types import (
CallToolResult,
DiscoverResult,
EmptyResult,
ErrorData,
Implementation,
JSONRPCError,
JSONRPCResponse,
@ -153,6 +155,39 @@ async def test_modern_response_carries_no_session_id_header() -> None:
assert "mcp-session-id" not in response.headers
@requirement("hosting:http:modern:notification-post-202")
@pytest.mark.parametrize("json_response", [True, False], ids=["json", "sse"])
@pytest.mark.parametrize("stateless_http", [True, False], ids=["stateless-flag", "default"])
async def test_modern_notification_post_is_acknowledged_202_and_a_posted_response_is_rejected(
json_response: bool, stateless_http: bool
) -> None:
"""A 2026-07-28 notification POST is answered 202 with no body; a posted response is 400 INVALID_REQUEST.
Spec-permitted (streamable-http §Sending Messages item 5): the server may accept (202) or refuse
(4xx) a notification POST, and the SDK accepts -- the same answer the legacy leg gives, so a
client's courtesy `notifications/cancelled` is not met with an error on one era only.
Spec-mandated (item 4): clients MUST NOT post responses, so one is refused. Driven through the
mounted app so the manager's header routing is in the path, under both response modes and both
values of the legacy-only `stateless_http` flag (neither is read before the modern entry answers).
"""
notification = {"jsonrpc": "2.0", "method": "notifications/cancelled", "params": {"requestId": 1}}
posted_response: dict[str, Any] = {"jsonrpc": "2.0", "id": 1, "result": {}}
async with mounted_app(_server(), json_response=json_response, stateless_http=stateless_http) as (http, _):
acknowledged = await http.post(
"/mcp", json=notification, headers=_modern_headers(method="notifications/cancelled")
)
refused = await http.post("/mcp", json=posted_response, headers=_modern_headers(method="tools/list"))
assert (acknowledged.status_code, acknowledged.content) == (202, b"")
assert "mcp-session-id" not in acknowledged.headers
assert refused.status_code == 400
assert JSONRPCError.model_validate(refused.json()) == JSONRPCError(
jsonrpc="2.0",
id=None,
error=ErrorData(code=INVALID_REQUEST, message="Body must be a single JSON-RPC request or notification object"),
)
@requirement("hosting:http:modern:initialize-removed")
async def test_modern_initialize_is_method_not_found() -> None:
"""A 2026-07-28 initialize request that carries a valid envelope is answered METHOD_NOT_FOUND at HTTP 404.