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refactor(mcp): add typed channel capability helper

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Co-Authored-By: Virgil <virgil@lethean.io>
This commit is contained in:
Virgil 2026-04-02 14:30:04 +00:00
parent af3cf3c8e3
commit fa9a5eed28
2 changed files with 100 additions and 23 deletions
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45
pkg/mcp/notify.go
View file

@ -90,6 +90,34 @@ var channelCapabilityList = []string{
ChannelTestResult,
}
// ChannelCapabilitySpec describes the experimental claude/channel capability.
//
// spec := ChannelCapabilitySpec{
// Version: "1",
// Description: "Push events into client sessions via named channels",
// Channels: ChannelCapabilityChannels(),
// }
type ChannelCapabilitySpec struct {
Version string `json:"version"`
Description string `json:"description"`
Channels []string `json:"channels"`
}
// Map converts the typed capability into the wire-format map expected by the SDK.
//
// caps := ChannelCapabilitySpec{
// Version: "1",
// Description: "Push events into client sessions via named channels",
// Channels: ChannelCapabilityChannels(),
// }.Map()
func (c ChannelCapabilitySpec) Map() map[string]any {
return map[string]any{
"version": c.Version,
"description": c.Description,
"channels": slices.Clone(c.Channels),
}
}
// ChannelNotification is the payload sent through the experimental channel
// notification method.
//
@ -280,11 +308,18 @@ func (e *notificationError) Error() string {
// for claude/channel, registered during New().
func channelCapability() map[string]any {
return map[string]any{
"claude/channel": map[string]any{
"version": "1",
"description": "Push events into client sessions via named channels",
"channels": channelCapabilityChannels(),
},
"claude/channel": ClaudeChannelCapability().Map(),
}
}
// ClaudeChannelCapability returns the typed experimental capability descriptor.
//
// cap := ClaudeChannelCapability()
func ClaudeChannelCapability() ChannelCapabilitySpec {
return ChannelCapabilitySpec{
Version: "1",
Description: "Push events into client sessions via named channels",
Channels: channelCapabilityChannels(),
}
}

78
pkg/mcp/notify_test.go
View file

@ -59,6 +59,36 @@ func readNotificationMessage(t *testing.T, conn net.Conn) <-chan notificationRea
return resultCh
}
func readNotificationMessageUntil(t *testing.T, conn net.Conn, match func(map[string]any) bool) <-chan notificationReadResult {
t.Helper()
resultCh := make(chan notificationReadResult, 1)
scanner := bufio.NewScanner(conn)
scanner.Buffer(make([]byte, 64*1024), 10*1024*1024)
go func() {
for scanner.Scan() {
var msg map[string]any
if err := json.Unmarshal(scanner.Bytes(), &msg); err != nil {
resultCh <- notificationReadResult{err: err}
return
}
if match(msg) {
resultCh <- notificationReadResult{msg: msg}
return
}
}
if err := scanner.Err(); err != nil {
resultCh <- notificationReadResult{err: err}
return
}
resultCh <- notificationReadResult{err: context.DeadlineExceeded}
}()
return resultCh
}
func TestSendNotificationToAllClients_Good(t *testing.T) {
svc, err := New(Options{})
if err != nil {
@ -130,8 +160,10 @@ func TestSendNotificationToAllClients_Good_CustomNotification(t *testing.T) {
defer session.Close()
clientConn.SetDeadline(time.Now().Add(5 * time.Second))
scanner := bufio.NewScanner(clientConn)
scanner.Buffer(make([]byte, 64*1024), 10*1024*1024)
read := readNotificationMessageUntil(t, clientConn, func(msg map[string]any) bool {
return msg["method"] == loggingNotificationMethod
})
sent := make(chan struct{})
go func() {
@ -141,20 +173,17 @@ func TestSendNotificationToAllClients_Good_CustomNotification(t *testing.T) {
close(sent)
}()
if !scanner.Scan() {
t.Fatalf("failed to read notification: %v", scanner.Err())
}
select {
case <-sent:
case <-time.After(5 * time.Second):
t.Fatal("timed out waiting for notification send to complete")
}
var msg map[string]any
if err := json.Unmarshal(scanner.Bytes(), &msg); err != nil {
t.Fatalf("failed to unmarshal notification: %v", err)
res := <-read
if res.err != nil {
t.Fatalf("failed to read notification: %v", res.err)
}
msg := res.msg
if msg["method"] != loggingNotificationMethod {
t.Fatalf("expected method %q, got %v", loggingNotificationMethod, msg["method"])
}
@ -233,8 +262,10 @@ func TestChannelSendToSession_Good_CustomNotification(t *testing.T) {
defer session.Close()
clientConn.SetDeadline(time.Now().Add(5 * time.Second))
scanner := bufio.NewScanner(clientConn)
scanner.Buffer(make([]byte, 64*1024), 10*1024*1024)
read := readNotificationMessageUntil(t, clientConn, func(msg map[string]any) bool {
return msg["method"] == channelNotificationMethod
})
sent := make(chan struct{})
go func() {
@ -244,20 +275,17 @@ func TestChannelSendToSession_Good_CustomNotification(t *testing.T) {
close(sent)
}()
if !scanner.Scan() {
t.Fatalf("failed to read custom notification: %v", scanner.Err())
}
select {
case <-sent:
case <-time.After(5 * time.Second):
t.Fatal("timed out waiting for notification send to complete")
}
var msg map[string]any
if err := json.Unmarshal(scanner.Bytes(), &msg); err != nil {
t.Fatalf("failed to unmarshal notification: %v", err)
res := <-read
if res.err != nil {
t.Fatalf("failed to read custom notification: %v", res.err)
}
msg := res.msg
if msg["method"] != channelNotificationMethod {
t.Fatalf("expected method %q, got %v", channelNotificationMethod, msg["method"])
}
@ -321,6 +349,20 @@ func TestChannelCapability_Good_PublicHelpers(t *testing.T) {
t.Fatalf("expected public capability helper to match internal definition")
}
spec := ClaudeChannelCapability()
if spec.Version != "1" {
t.Fatalf("expected typed capability version 1, got %q", spec.Version)
}
if spec.Description == "" {
t.Fatal("expected typed capability description to be populated")
}
if !slices.Equal(spec.Channels, channelCapabilityChannels()) {
t.Fatalf("expected typed capability channels to match: got %v want %v", spec.Channels, channelCapabilityChannels())
}
if !reflect.DeepEqual(spec.Map(), want["claude/channel"].(map[string]any)) {
t.Fatal("expected typed capability map to match wire-format descriptor")
}
gotChannels := ChannelCapabilityChannels()
wantChannels := channelCapabilityChannels()
if !slices.Equal(gotChannels, wantChannels) {