Make MCP client initialization timeout configurable via ToolOptions by matiazo · Pull Request #212 · microsoft/Agent365-dotnet

matiazo · 2026-03-10T19:50:33Z

Summary

Add nullable McpClientInitializationTimeoutSeconds property to ToolOptions so consumers can override the MCP client initialization timeout
When not set (null), the MCP SDK default (60s) is used — no behavioral change for existing consumers
When set, both McpClientOptions.InitializationTimeout and HttpClient.Timeout are configured to match

Motivation

Consumers connecting to the MCP platform may experience OperationCanceledException when downstream dependencies are slow. The MCP SDK's default 60-second initialization timeout is not configurable through ToolOptions, leaving no way for consumers to adjust it for their agents.

Usage

// Default behavior — no change needed, SDK default timeout applies
var options = new ToolOptions();
await configService.GetMcpClientToolsAsync(turnContext, serverConfig, token, options);

// Custom timeout for slow environments
var options = new ToolOptions
{
    McpClientInitializationTimeoutSeconds = 180 // 3 minutes
};
await configService.GetMcpClientToolsAsync(turnContext, serverConfig, token, options);

Changes

src/Tooling/Core/Models/ToolOptions.cs — Add int? McpClientInitializationTimeoutSeconds property
src/Tooling/Core/Services/McpToolServerConfigurationService.cs — Apply timeout only when explicitly set

Test plan

Verified default behavior (null) uses MCP SDK default timeout
Verified explicit value is applied to both McpClientOptions.InitializationTimeout and HttpClient.Timeout
Built and tested end-to-end with sample-agent against MCP platform

Generated with Claude Code

Add nullable McpClientInitializationTimeoutSeconds property to ToolOptions so consumers can override the MCP client initialization timeout. When null (default), the MCP SDK default is used. When set, both McpClientOptions and HttpClient.Timeout are configured to match. Co-Authored-By: Claude Code <noreply@anthropic.com>

Copilot

Pull request overview

This PR adds an opt-in configuration surface to the Tooling layer so SDK consumers can override the MCP client initialization timeout (handshake/connection setup) via ToolOptions, helping environments where MCP initialization regularly exceeds the SDK default.

Changes:

Added ToolOptions.McpClientInitializationTimeoutSeconds (nullable) to allow overriding MCP initialization timeout.
When set, applies the timeout to both HttpClient.Timeout and McpClientOptions.InitializationTimeout during MCP client creation.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/Tooling/Core/Models/ToolOptions.cs	Introduces a new nullable option to configure MCP client initialization timeout (in seconds).
src/Tooling/Core/Services/McpToolServerConfigurationService.cs	Applies the configured timeout when creating the HTTP client and MCP client options for MCP client initialization.

- Add input validation (1-600s range) with ArgumentOutOfRangeException - Document valid range in ToolOptions XML docs - Preserve original SDK behavior when timeout is null: call McpClientFactory.CreateAsync without McpClientOptions instead of passing a default instance - Add 13 unit tests covering: null default, valid/invalid values, ArgumentOutOfRangeException for out-of-bounds inputs Co-Authored-By: Claude Code <noreply@anthropic.com>

…mcp-timeout

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

Copilot · 2026-04-15T17:17:48Z

+                if (timeoutSeconds < 1 || timeoutSeconds > 600)
+                {
+                    throw new ArgumentOutOfRangeException(
+                        nameof(toolOptions),


ArgumentOutOfRangeException is using nameof(toolOptions) as the parameter name, which makes it harder for consumers to identify the offending argument/property. Use the actual property name (e.g., nameof(ToolOptions.McpClientInitializationTimeoutSeconds) or "McpClientInitializationTimeoutSeconds") so the exception clearly points to the misconfigured value.

Suggested change

nameof(toolOptions),

nameof(ToolOptions.McpClientInitializationTimeoutSeconds),

Copilot · 2026-04-15T17:17:49Z

+                // Only pass McpClientOptions when a custom timeout is set to preserve default SDK behavior
+                if (toolOptions.McpClientInitializationTimeoutSeconds.HasValue)
+                {
+                    var clientOptions = new McpClientOptions
+                    {
+                        InitializationTimeout = TimeSpan.FromSeconds(toolOptions.McpClientInitializationTimeoutSeconds.Value),
+                    };


The timeout value is validated earlier and stored in timeoutSeconds, but it’s recomputed here from toolOptions...Value again. To reduce duplication and ensure a single source of truth, compute a TimeSpan initializationTimeout once (inside the HasValue block where validation happens) and reuse it for both httpClient.Timeout (if you keep it) and McpClientOptions.InitializationTimeout.

Copilot · 2026-04-15T17:17:49Z

+    public class McpClientInitializationTimeoutTests
+    {
+        private readonly Mock<ILogger<IMcpToolServerConfigurationService>> _loggerMock;
+        private readonly Mock<IConfiguration> _configurationMock;


_configurationMock is initialized but not used anywhere in this test class. Removing it reduces noise and avoids implying shared configuration setup that isn’t actually applied.

Copilot · 2026-04-15T17:17:49Z

+        public McpClientInitializationTimeoutTests()
+        {
+            _loggerMock = new Mock<ILogger<IMcpToolServerConfigurationService>>();
+            _configurationMock = new Mock<IConfiguration>();


_configurationMock is initialized but not used anywhere in this test class. Removing it reduces noise and avoids implying shared configuration setup that isn’t actually applied.

Copilot · 2026-04-15T17:17:50Z

+            // Assert - ArgumentOutOfRangeException is wrapped in InvalidOperationException by the catch block
+            var ex = await act.Should().ThrowAsync<InvalidOperationException>();
+            ex.WithInnerException<ArgumentOutOfRangeException>();


This assertion is tightly coupled to the current exception-wrapping behavior. In the service diff, the ArgumentOutOfRangeException is thrown before the local try block in CreateMcpClientWithAuthHandlers, so whether it’s wrapped depends on higher-level code paths. Prefer asserting directly on ArgumentOutOfRangeException (or asserting either direct or wrapped) so the test remains stable if exception handling/refactoring changes.

Suggested change

// Assert - ArgumentOutOfRangeException is wrapped in InvalidOperationException by the catch block

var ex = await act.Should().ThrowAsync<InvalidOperationException>();

ex.WithInnerException<ArgumentOutOfRangeException>();

// Assert - invalid timeout should surface an ArgumentOutOfRangeException either directly

// or wrapped by a higher-level InvalidOperationException depending on the call path.

var exception = await Record.ExceptionAsync(act);

exception.Should().NotBeNull();

(exception is ArgumentOutOfRangeException ||

exception is InvalidOperationException { InnerException: ArgumentOutOfRangeException })

.Should().BeTrue("an invalid timeout should result in an ArgumentOutOfRangeException, either directly or wrapped");

Copilot · 2026-04-15T17:17:50Z

+                // Only pass McpClientOptions when a custom timeout is set to preserve default SDK behavior
+                if (toolOptions.McpClientInitializationTimeoutSeconds.HasValue)


The added tests do not validate the core behavior change: that a configured timeout is actually applied to MCP client creation (and that the default path does not pass McpClientOptions). Consider adding a unit test that can verify the effective timeout usage—this may require refactoring to inject a factory/wrapper around McpClientFactory.CreateAsync or exposing a seam for inspecting the HttpClient/McpClientOptions used during creation.

matiazo requested a review from a team as a code owner March 10, 2026 19:50

matiazo requested review from Copilot, rahuldevikar761 and sellakumaran March 10, 2026 19:50

Copilot started reviewing on behalf of matiazo March 10, 2026 19:51 View session

Copilot AI reviewed Mar 10, 2026

View reviewed changes

ajmfehr approved these changes Apr 3, 2026

View reviewed changes

Merge remote-tracking branch 'origin/main' into feature/configurable-…

21f76df

…mcp-timeout

Copilot AI review requested due to automatic review settings April 15, 2026 17:10

Copilot AI reviewed Apr 15, 2026

View reviewed changes

Copilot started reviewing on behalf of matiazo April 15, 2026 19:08 View session

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Make MCP client initialization timeout configurable via ToolOptions#212

Make MCP client initialization timeout configurable via ToolOptions#212
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	nameof(toolOptions),
	nameof(ToolOptions.McpClientInitializationTimeoutSeconds),

-            // Assert - ArgumentOutOfRangeException is wrapped in InvalidOperationException by the catch block
-            var ex = await act.Should().ThrowAsync<InvalidOperationException>();
-            ex.WithInnerException<ArgumentOutOfRangeException>();
+            // Assert - invalid timeout should surface an ArgumentOutOfRangeException either directly
+            // or wrapped by a higher-level InvalidOperationException depending on the call path.
+            var exception = await Record.ExceptionAsync(act);
+            exception.Should().NotBeNull();
+            (exception is ArgumentOutOfRangeException ||
+                exception is InvalidOperationException { InnerException: ArgumentOutOfRangeException })
+                .Should().BeTrue("an invalid timeout should result in an ArgumentOutOfRangeException, either directly or wrapped");

		// Only pass McpClientOptions when a custom timeout is set to preserve default SDK behavior
		if (toolOptions.McpClientInitializationTimeoutSeconds.HasValue)

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matiazo commented Mar 10, 2026

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