Replace Mcp approvals with Function approvals

[jozkee]

Strawman proposal for replacing McpServerToolApprovalRequestContent and McpServerToolApprovalResponseContent with Function approval types.

#6492 (comment)
cc @westey-m

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull request overview

This PR refactors the approval mechanism for tool calls by replacing MCP-specific approval types (McpServerToolApprovalRequestContent and McpServerToolApprovalResponseContent) with generalized FunctionApprovalRequestContent and FunctionApprovalResponseContent types. This allows the function approval system to handle both regular function calls and MCP server tool calls uniformly.

Key Changes:

• Deleted MCP-specific approval content types and consolidated them into the existing Function approval types
• Changed FunctionApprovalRequestContent and FunctionApprovalResponseContent to accept AIContent instead of FunctionCallContent, enabling support for multiple call types (e.g., FunctionCallContent, McpServerToolCallContent)
• Updated property names from FunctionCall to CallContent to reflect the more general nature
• Added pattern matching logic in FunctionInvokingChatClient to handle mixed approval scenarios where only FunctionCallContent approvals are processed
• Updated OpenAI response client to map MCP approval items to the generalized approval types
• Added comprehensive tests for mixed approval scenarios

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs	Deleted - functionality replaced by generalized FunctionApprovalRequestContent
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs	Deleted - functionality replaced by generalized FunctionApprovalResponseContent
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs	Changed to accept AIContent instead of FunctionCallContent; renamed property FunctionCall → CallContent
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs	Changed to accept AIContent instead of FunctionCallContent; renamed property FunctionCall → CallContent
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs	Removed McpServerToolApprovalRequestContent from JSON polymorphic type hierarchy
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs	Removed McpServerToolApprovalResponseContent from JSON polymorphic type hierarchy
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs	Removed commented-out type discriminators for deleted MCP approval types
src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.Defaults.cs	Removed JSON serialization registration for deleted MCP approval types
src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs	Added pattern matching to process only FunctionCallContent from approval types; updated struct to be readonly with init properties; fixed spelling error
src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs	Updated to map MCP approval items to generalized FunctionApprovalRequestContent and FunctionApprovalResponseContent with McpServerToolCallContent
test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs	Changed namespace; updated assertions to use CallContent property; added comprehensive tests for mixed approval scenarios
test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs	Updated test assertions to use generalized approval types
test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs	Updated test assertions and approval response creation logic; reordered test execution calls
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs	Updated tests to use CallContent property and added type assertions for deserialized content
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs	Updated tests to use CallContent property and added type assertions for deserialized content
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs	Commented out MCP-specific test case; updated deserialization type
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs	Commented out MCP-specific test case with note about experimental status
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/AIContentTests.cs	Updated test to use generalized approval types with MCP content

[stephentoub]

Can you do this instead with a when clause on the case? (same for the next case below)

[stephentoub]

Why is this needed? Is that just to make accessing this less verbose? Otherwise isn't this just Response.CallContent?

[jozkee]

Because Response.CallContent is now AIContent, I would have to do a cast or type check later if I don't save it here.

[jozkee]

Is that just to make accessing this less verbose?

Yes but not for the sake of using less dots/properties.

[stephentoub]

If the concern is perf, the extra size is very likely more impactful. If you don't want to cast at the call site, I suggest changing the property to access/cast it from Response.

[jozkee]

It wasn't for perf, it felt less risky to have the concrete-type property and leverage that the initialization already validated it was a FunctionCallContent. I applied your suggestion anyway since is functionally the same.