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Default draft protocol support: sessionless + handshake-less (SEP-2575 + SEP-2567) (#1610)

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Stephen Halter 2026-06-23 21:24:22 -07:00 • committed by GitHub
commit 6c323e783b
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1 changed files with 5704 additions and 712 deletions
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85
tests/ModelContextProtocol.Tests/Client/MrtrIntegrationTests.cs
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@ -31,7 +31,7 @@ public class MrtrIntegrationTests : ClientServerTestBase
services.AddLogging(builder => builder.SetMinimumLevel(LogLevel.Debug));
services.Configure<McpServerOptions>(options =>
{
options.ProtocolVersion = "DRAFT-2026-v1";
options.ProtocolVersion = "2026-07-28";
_messageTracker.AddFilters(options.Filters.Message);
});
@ -95,14 +95,14 @@ public class MrtrIntegrationTests : ClientServerTestBase
// input resolution failures back to the server.
StartServer();
var clientOptions = new McpClientOptions { ProtocolVersion = "DRAFT-2026-v1" };
var clientOptions = new McpClientOptions { ProtocolVersion = "2026-07-28" };
clientOptions.Handlers.ElicitationHandler = (request, ct) =>
{
throw new InvalidOperationException("Client-side elicitation failure");
};
await using var client = await CreateMcpClientForServer(clientOptions);
Assert.Equal("DRAFT-2026-v1", client.NegotiatedProtocolVersion);
Assert.Equal("2026-07-28", client.NegotiatedProtocolVersion);
// The client handler throws during input resolution, so the exception
// escapes ResolveInputRequestAsync and surfaces directly to the caller.
@ -130,7 +130,7 @@ public class MrtrIntegrationTests : ClientServerTestBase
// SendMessageAsync should throw InvalidOperationException if the message is a
// JsonRpcRequest, regardless of MRTR state. Use SendRequestAsync for requests.
StartServer();
var clientOptions = new McpClientOptions { ProtocolVersion = "DRAFT-2026-v1" };
var clientOptions = new McpClientOptions { ProtocolVersion = "2026-07-28" };
clientOptions.Handlers.ElicitationHandler = (request, ct) =>
new ValueTask<ElicitResult>(new ElicitResult { Action = "accept" });
@ -155,7 +155,7 @@ public class MrtrIntegrationTests : ClientServerTestBase
var clientToServer = new Pipe();
var serverToClient = new Pipe();
var clientOptions = new McpClientOptions { ProtocolVersion = "DRAFT-2026-v1" };
var clientOptions = new McpClientOptions { ProtocolVersion = "2026-07-28" };
clientOptions.Handlers.ElicitationHandler = (request, ct) =>
new ValueTask<ElicitResult>(new ElicitResult { Action = "accept" });
clientOptions.Handlers.SamplingHandler = (request, progress, ct) =>
@ -165,7 +165,7 @@ public class MrtrIntegrationTests : ClientServerTestBase
Model = "test-model"
});
// Start the client task - it will send initialize and block waiting for response
// Start the client task — it will send server/discover (draft) and block waiting for response
var clientTask = McpClient.CreateAsync(
new StreamClientTransport(
clientToServer.Writer.AsStream(),
@ -175,37 +175,34 @@ public class MrtrIntegrationTests : ClientServerTestBase
loggerFactory: LoggerFactory,
cancellationToken: TestContext.Current.CancellationToken);
// Simulate server: read initialize request, respond with experimental version
// Simulate server: read server/discover request, respond with a DiscoverResult
// that advertises support for the experimental version.
var serverReader = new StreamReader(clientToServer.Reader.AsStream());
var serverWriter = serverToClient.Writer.AsStream();
// Read the initialize request from client
var initLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(initLine);
var initRequest = JsonSerializer.Deserialize<JsonRpcRequest>(initLine, McpJsonUtilities.DefaultOptions);
Assert.NotNull(initRequest);
Assert.Equal("initialize", initRequest.Method);
// Read the server/discover request from client (draft revision skips initialize per SEP-2575).
var discoverLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(discoverLine);
var discoverRequest = JsonSerializer.Deserialize<JsonRpcRequest>(discoverLine, McpJsonUtilities.DefaultOptions);
Assert.NotNull(discoverRequest);
Assert.Equal(RequestMethods.ServerDiscover, discoverRequest.Method);
// Respond with experimental protocol version (MRTR negotiated)
var initResponse = new JsonRpcResponse
// Respond with a DiscoverResult that includes the experimental version in supportedVersions.
var discoverResponse = new JsonRpcResponse
{
Id = initRequest.Id,
Result = JsonSerializer.SerializeToNode(new InitializeResult
Id = discoverRequest.Id,
Result = JsonSerializer.SerializeToNode(new DiscoverResult
{
ProtocolVersion = "DRAFT-2026-v1",
SupportedVersions = new List<string> { "2026-07-28" },
Capabilities = new ServerCapabilities(),
ServerInfo = new Implementation { Name = "MockMrtrServer", Version = "1.0" }
ServerInfo = new Implementation { Name = "MockMrtrServer", Version = "1.0" },
}, McpJsonUtilities.DefaultOptions),
};
await WriteJsonRpcAsync(serverWriter, initResponse);
await WriteJsonRpcAsync(serverWriter, discoverResponse);
// Read the initialized notification from client
var initializedLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(initializedLine);
// Client is now connected with MRTR negotiated
// Client is now connected with MRTR negotiated (no initialized notification under draft).
await using var client = await clientTask;
Assert.Equal("DRAFT-2026-v1", client.NegotiatedProtocolVersion);
Assert.Equal("2026-07-28", client.NegotiatedProtocolVersion);
// Now simulate the non-compliant server sending a legacy elicitation/create request
var legacyRequest = new JsonRpcRequest
@ -253,8 +250,9 @@ public class MrtrIntegrationTests : ClientServerTestBase
var clientToServer = new Pipe();
var serverToClient = new Pipe();
// Client does NOT set DRAFT-2026-v1 - standard protocol only
var clientOptions = new McpClientOptions();
// Client is pinned to a legacy protocol version, so it performs the initialize
// handshake and the session is treated as non-MRTR.
var clientOptions = new McpClientOptions { ProtocolVersion = "2025-03-26" };
clientOptions.Handlers.ElicitationHandler = (request, ct) =>
new ValueTask<ElicitResult>(new ElicitResult
{
@ -408,7 +406,9 @@ public class MrtrIntegrationTests : ClientServerTestBase
var clientToServer = new Pipe();
var serverToClient = new Pipe();
var clientOptions = new McpClientOptions();
// Pin to the draft revision so the client performs the server/discover handshake and
// treats InputRequiredResult as an MRTR round-trip.
var clientOptions = new McpClientOptions { ProtocolVersion = "2026-07-28" };
clientOptions.Handlers.ElicitationHandler = (_, _) =>
new ValueTask<ElicitResult>(new ElicitResult
{
@ -431,30 +431,27 @@ public class MrtrIntegrationTests : ClientServerTestBase
var serverReader = new StreamReader(clientToServer.Reader.AsStream());
var serverWriter = serverToClient.Writer.AsStream();
// Initialize handshake - negotiate DRAFT-2026-v1 so the client treats InputRequiredResult as MRTR.
var initLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(initLine);
var initRequest = JsonSerializer.Deserialize<JsonRpcRequest>(initLine, McpJsonUtilities.DefaultOptions);
Assert.NotNull(initRequest);
Assert.Equal("initialize", initRequest.Method);
// server/discover handshake - negotiate 2026-07-28 so the client treats InputRequiredResult as MRTR.
var discoverLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(discoverLine);
var discoverRequest = JsonSerializer.Deserialize<JsonRpcRequest>(discoverLine, McpJsonUtilities.DefaultOptions);
Assert.NotNull(discoverRequest);
Assert.Equal("server/discover", discoverRequest.Method);
var initResponse = new JsonRpcResponse
var discoverResponse = new JsonRpcResponse
{
Id = initRequest.Id,
Result = JsonSerializer.SerializeToNode(new InitializeResult
Id = discoverRequest.Id,
Result = JsonSerializer.SerializeToNode(new DiscoverResult
{
ProtocolVersion = "DRAFT-2026-v1",
SupportedVersions = ["2026-07-28"],
Capabilities = new ServerCapabilities { Tools = new() },
ServerInfo = new Implementation { Name = "MrtrServer", Version = "1.0" }
}, McpJsonUtilities.DefaultOptions),
};
await WriteJsonRpcAsync(serverWriter, initResponse);
var initializedLine = await serverReader.ReadLineAsync(TestContext.Current.CancellationToken);
Assert.NotNull(initializedLine);
await WriteJsonRpcAsync(serverWriter, discoverResponse);
await using var client = await clientTask;
Assert.Equal("DRAFT-2026-v1", client.NegotiatedProtocolVersion);
Assert.Equal("2026-07-28", client.NegotiatedProtocolVersion);
var cancellationToken = TestContext.Current.CancellationToken;