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mcp: do not exclude Notifications from carrying InitializeParams in Meta (#1049)

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Fixes #1043
This commit is contained in:
Guglielmo Colombo 2026-07-06 17:10:26 +02:00 • committed by GitHub
commit 224a240875
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GPG key ID: B5690EEEBB952194
2 changed files with 8 additions and 31 deletions
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13
mcp/shared.go
View file

@ -515,11 +515,10 @@ type validatedMeta struct {
// the >= 2026-07-28 protocol via the `_meta` field.
// If the request has no _meta, or no protocolVersion in _meta, it returns a non-nil
// validatedMeta with usesNewProtocol set to false, and a nil error.
// If the request has a protocolVersion in _meta:
// - For notifications, it returns usesNewProtocol set to true and a nil initializeParams.
// - For call requests, it validates the presence of clientInfo and clientCapabilities in _meta.
// If either is missing or invalid, it returns nil and a non-nil error. Otherwise, it returns
// usesNewProtocol set to true and the populated initializeParams.
// If the request has a protocolVersion in _meta it validates the presence of clientInfo
// and clientCapabilities in _meta. If either is missing or invalid, it returns nil and
// a non-nil error. Otherwise, it returns usesNewProtocol set to true and the populated
// initializeParams.
func validateRequestMeta(req *jsonrpc.Request) (*validatedMeta, error) {
meta := extractRequestMeta(req.Params)
if meta == nil {
@ -529,10 +528,6 @@ func validateRequestMeta(req *jsonrpc.Request) (*validatedMeta, error) {
if !ok || protocolVersion < protocolVersion20260728 {
return &validatedMeta{usesNewProtocol: false, initializeParams: nil}, nil
}
// Notifications do not carry full client identity.
if !req.IsCall() {
return &validatedMeta{usesNewProtocol: true, initializeParams: nil}, nil
}
clientInfo, ok := decodeMetaValue[*Implementation](meta, MetaKeyClientInfo)
if !ok {
return nil, &jsonrpc.Error{

26
mcp/shared_test.go
View file

@ -18,7 +18,6 @@ func TestValidateRequestMeta(t *testing.T) {
tests := []struct {
name string
method string
isNotification bool
params any
wantUsesNew bool
wantLogLevel LoggingLevel
@ -84,18 +83,6 @@ func TestValidateRequestMeta(t *testing.T) {
wantUsesNew: false,
wantErrContains: MetaKeyClientCapabilities,
},
{
name: "notifications exempt from required fields",
method: notificationCancelled,
isNotification: true,
params: map[string]any{
"_meta": map[string]any{
MetaKeyProtocolVersion: protocolVersion20260728,
},
"requestId": "r1",
},
wantUsesNew: true,
},
{
name: "malformed _meta is ignored",
method: methodCallTool,
@ -141,16 +128,11 @@ func TestValidateRequestMeta(t *testing.T) {
default:
raw = mustMarshal(tc.params)
}
req := &jsonrpc.Request{Method: tc.method, Params: raw}
if !tc.isNotification {
req.ID = jsonrpc.ID{}
// Give the request an ID by parsing one.
id, err := jsonrpc.MakeID("test")
if err != nil {
t.Fatal(err)
}
req.ID = id
id, err := jsonrpc.MakeID("test")
if err != nil {
t.Fatal(err)
}
req := &jsonrpc.Request{Method: tc.method, Params: raw, ID: id}
vmeta, err := validateRequestMeta(req)
usesNew := vmeta != nil && vmeta.usesNewProtocol