modelcontextprotocol/csharp-sdk
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Propagate tool call exceptions through filters (#844)

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* Add McpProtocolException specifically for JSON-RPC errors
This commit is contained in:
Stephen Halter 2025-10-14 21:10:55 -05:00 • committed by GitHub
commit 3255adb4d6
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GPG key ID: B5690EEEBB952194
4 changed files with 334 additions and 163 deletions
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33
tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsFilterTests.cs
View file

@ -58,7 +58,18 @@ public class McpServerBuilderExtensionsFilterTests : ClientServerTestBase
var logger = GetLogger(request.Services, "CallToolFilter");
var primitiveId = request.MatchedPrimitive?.Id ?? "unknown";
logger.LogInformation($"CallToolFilter executed for tool: {primitiveId}");
return await next(request, cancellationToken);
try
{
return await next(request, cancellationToken);
}
catch (Exception ex)
{
return new CallToolResult
{
Content = [new TextContentBlock { Type = "text", Text = $"Error from filter: {ex.Message}" }],
IsError = true
};
}
})
.AddListPromptsFilter((next) => async (request, cancellationToken) =>
{
@ -162,6 +173,20 @@ public class McpServerBuilderExtensionsFilterTests : ClientServerTestBase
Assert.Equal("CallToolFilter", logMessage.Category);
}
[Fact]
public async Task AddCallToolFilter_Catches_Exception_From_Tool()
{
await using McpClient client = await CreateMcpClientForServer();
var result = await client.CallToolAsync("throwing_tool_method", cancellationToken: TestContext.Current.CancellationToken);
Assert.True(result.IsError);
Assert.NotNull(result.Content);
var textContent = Assert.Single(result.Content);
var textBlock = Assert.IsType<TextContentBlock>(textContent);
Assert.Equal("Error from filter: This tool always throws an exception", textBlock.Text);
}
[Fact]
public async Task AddListPromptsFilter_Logs_When_ListPrompts_Called()
{
@ -286,6 +311,12 @@ public class McpServerBuilderExtensionsFilterTests : ClientServerTestBase
{
return "test result";
}
[McpServerTool]
public static string ThrowingToolMethod()
{
throw new InvalidOperationException("This tool always throws an exception");
}
}
[McpServerPromptType]

10
tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsPromptsTests.cs
View file

@ -62,7 +62,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
};
default:
throw new McpException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
}
})
.WithGetPromptHandler(async (request, cancellationToken) =>
@ -78,7 +78,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
};
default:
throw new McpException($"Unknown prompt '{request.Params?.Name}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unknown prompt '{request.Params?.Name}'", McpErrorCode.InvalidParams);
}
})
.WithPrompts<SimplePrompts>();
@ -190,7 +190,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
{
await using McpClient client = await CreateMcpClientForServer();
await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
await Assert.ThrowsAsync<McpProtocolException>(async () => await client.GetPromptAsync(
nameof(SimplePrompts.ThrowsException),
cancellationToken: TestContext.Current.CancellationToken));
}
@ -200,7 +200,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
{
await using McpClient client = await CreateMcpClientForServer();
var e = await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
var e = await Assert.ThrowsAsync<McpProtocolException>(async () => await client.GetPromptAsync(
"NotRegisteredPrompt",
cancellationToken: TestContext.Current.CancellationToken));
@ -212,7 +212,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
{
await using McpClient client = await CreateMcpClientForServer();
var e = await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
var e = await Assert.ThrowsAsync<McpProtocolException>(async () => await client.GetPromptAsync(
"returns_chat_messages",
cancellationToken: TestContext.Current.CancellationToken));

10
tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsResourcesTests.cs
View file

@ -62,7 +62,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
};
default:
throw new McpException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
}
})
.WithListResourceTemplatesHandler(async (request, cancellationToken) =>
@ -91,7 +91,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
}],
};
default:
throw new McpException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
}
})
.WithReadResourceHandler(async (request, cancellationToken) =>
@ -109,7 +109,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
};
}
throw new McpException($"Resource not found: {request.Params?.Uri}");
throw new McpProtocolException($"Resource not found: {request.Params?.Uri}");
})
.WithResources<SimpleResources>();
}
@ -235,7 +235,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
{
await using McpClient client = await CreateMcpClientForServer();
await Assert.ThrowsAsync<McpException>(async () => await client.ReadResourceAsync(
await Assert.ThrowsAsync<McpProtocolException>(async () => await client.ReadResourceAsync(
$"resource://mcp/{nameof(SimpleResources.ThrowsException)}",
cancellationToken: TestContext.Current.CancellationToken));
}
@ -245,7 +245,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
{
await using McpClient client = await CreateMcpClientForServer();
var e = await Assert.ThrowsAsync<McpException>(async () => await client.ReadResourceAsync(
var e = await Assert.ThrowsAsync<McpProtocolException>(async () => await client.ReadResourceAsync(
"test:///NotRegisteredResource",
cancellationToken: TestContext.Current.CancellationToken));

6
tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs
View file

@ -90,7 +90,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
};
default:
throw new McpException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unexpected cursor: '{cursor}'", McpErrorCode.InvalidParams);
}
})
.WithCallToolHandler(async (request, cancellationToken) =>
@ -106,7 +106,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
};
default:
throw new McpException($"Unknown tool: '{request.Params?.Name}'", McpErrorCode.InvalidParams);
throw new McpProtocolException($"Unknown tool: '{request.Params?.Name}'", McpErrorCode.InvalidParams);
}
})
.WithTools<EchoTool>(serializerOptions: BuilderToolsJsonContext.Default.Options);
@ -388,7 +388,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
{
await using McpClient client = await CreateMcpClientForServer();
var e = await Assert.ThrowsAsync<McpException>(async () => await client.CallToolAsync(
var e = await Assert.ThrowsAsync<McpProtocolException>(async () => await client.CallToolAsync(
"NotRegisteredTool",
cancellationToken: TestContext.Current.CancellationToken));