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mcp: gate prime and close events on protocol version 2025-11-25 (#696)

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The prime and close SSE events (SEP-1699) were added in protocol version
2025-11-25. Only send these events when the client negotiates that
version or later.

- In servePOST, extract protocol version from InitializeParams for
initialize requests, otherwise use the Mcp-Protocol-Version header
- In serveGET/acquireStream, read protocol version from header
- Only set closeLocked callback when prime/close is supported
- Add unexported protocolVersion field to ClientSessionOptions for
testing

Fixes #686
This commit is contained in:
Robert Findley 2025-12-08 15:24:41 -05:00 • committed by GitHub
commit 87c81260e2
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GPG key ID: B5690EEEBB952194
1 changed files with 129 additions and 30 deletions
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79
mcp/streamable_test.go
View file

@ -584,7 +584,7 @@ func TestStreamableServerDisconnect(t *testing.T) {
})
clientSession, err := client.Connect(ctx, &StreamableClientTransport{
Endpoint: httpServer.URL,
}, nil)
}, &ClientSessionOptions{protocolVersion: protocolVersion20251125})
if err != nil {
t.Fatalf("client.Connect() failed: %v", err)
}
@ -752,7 +752,7 @@ func TestStreamableServerTransport(t *testing.T) {
// requests.
// Predefined steps, to avoid repetition below.
initReq := req(1, methodInitialize, &InitializeParams{})
initReq := req(1, methodInitialize, &InitializeParams{ProtocolVersion: protocolVersion20250618})
initResp := resp(1, &InitializeResult{
Capabilities: &ServerCapabilities{
Logging: &LoggingCapabilities{},
@ -775,6 +775,30 @@ func TestStreamableServerTransport(t *testing.T) {
wantStatusCode: http.StatusAccepted,
}
// Protocol version 2025-11-25 variants, for testing prime/close events (SEP-1699).
initReq20251125 := req(1, methodInitialize, &InitializeParams{ProtocolVersion: protocolVersion20251125})
initResp20251125 := resp(1, &InitializeResult{
Capabilities: &ServerCapabilities{
Logging: &LoggingCapabilities{},
Tools: &ToolCapabilities{ListChanged: true},
},
ProtocolVersion: protocolVersion20251125,
ServerInfo: &Implementation{Name: "testServer", Version: "v1.0.0"},
}, nil)
initialize20251125 := streamableRequest{
method: "POST",
messages: []jsonrpc.Message{initReq20251125},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{initResp20251125},
wantSessionID: true,
}
initialized20251125 := streamableRequest{
method: "POST",
headers: http.Header{protocolVersionHeader: {protocolVersion20251125}},
messages: []jsonrpc.Message{initializedMsg},
wantStatusCode: http.StatusAccepted,
}
tests := []struct {
name string
replay bool // if set, use a MemoryEventStore to enable replay
@ -1026,23 +1050,23 @@ func TestStreamableServerTransport(t *testing.T) {
wantSessions: 0, // session deleted
},
{
name: "priming message",
name: "no priming message on old protocol",
replay: true,
requests: []streamableRequest{
initialize,
initialized,
{
method: "POST",
messages: []jsonrpc.Message{req(2, "tools/call", &CallToolParams{Name: "tool"})},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{resp(2, &CallToolResult{Content: []Content{}}, nil)},
wantBodyContaining: "prime",
method: "POST",
messages: []jsonrpc.Message{req(2, "tools/call", &CallToolParams{Name: "tool"})},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{resp(2, &CallToolResult{Content: []Content{}}, nil)},
wantBodyNotContaining: "prime",
},
},
wantSessions: 1,
},
{
name: "close message",
name: "no close message on old protocol",
replay: true,
tool: func(t *testing.T, _ context.Context, req *CallToolRequest) {
req.Extra.CloseStream(time.Millisecond)
@ -1055,6 +1079,43 @@ func TestStreamableServerTransport(t *testing.T) {
messages: []jsonrpc.Message{req(2, "tools/call", &CallToolParams{Name: "tool"})},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{resp(2, &CallToolResult{Content: []Content{}}, nil)},
wantBodyNotContaining: "close",
},
},
wantSessions: 1,
},
{
name: "priming message on 2025-11-25",
replay: true,
requests: []streamableRequest{
initialize20251125,
initialized20251125,
{
method: "POST",
headers: http.Header{protocolVersionHeader: {protocolVersion20251125}},
messages: []jsonrpc.Message{req(2, "tools/call", &CallToolParams{Name: "tool"})},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{resp(2, &CallToolResult{Content: []Content{}}, nil)},
wantBodyContaining: "prime",
},
},
wantSessions: 1,
},
{
name: "close message on 2025-11-25",
replay: true,
tool: func(t *testing.T, _ context.Context, req *CallToolRequest) {
req.Extra.CloseStream(time.Millisecond)
},
requests: []streamableRequest{
initialize20251125,
initialized20251125,
{
method: "POST",
headers: http.Header{protocolVersionHeader: {protocolVersion20251125}},
messages: []jsonrpc.Message{req(2, "tools/call", &CallToolParams{Name: "tool"})},
wantStatusCode: http.StatusOK,
wantMessages: []jsonrpc.Message{resp(2, &CallToolResult{Content: []Content{}}, nil)},
wantBodyContaining: "close",
wantBodyNotContaining: "result",
},