MCP/Approvals stabilization

[Copilot]

Summary

This PR consolidates MCP server tool approval flow by making McpServerToolCallContent and McpServerToolResultContent inherit from FunctionCallContent and FunctionResultContent respectively, instead of having separate approval types.

Changes

• Extend function content types: Made McpServerToolCallContent extend FunctionCallContent and McpServerToolResultContent extend FunctionResultContent
• Remove specialized approval types: Deleted McpServerToolApprovalRequestContent and McpServerToolApprovalResponseContent classes - MCP approvals now use the existing FunctionApprovalRequestContent and FunctionApprovalResponseContent
• Add invocation flag: Added InformationalOnly property to FunctionCallContent (defaults to false). For McpServerToolCallContent, this defaults to true since MCP tool calls are informational
• Update OpenAI integration: Modified OpenAIResponsesChatClient to work with the unified approval model
• Add API compatibility suppressions: Documented breaking changes in CompatibilitySuppressions.xml
• Improved documentation: Added clarifying remarks about requestId vs function call ID, informational nature of McpServerToolCallContent, and authentication header usage for Headers property
• Fix case-insensitive Bearer token extraction: Use StringComparison.OrdinalIgnoreCase for case-insensitive auth scheme matching per RFC 7235, trim whitespace from both ends of header value, and allow flexible whitespace after "Bearer "

Impact

This reduces complexity by reusing existing function call/result abstractions rather than maintaining parallel MCP-specific approval types. The approval mechanism now works consistently for both regular function calls and MCP server tool calls.

Original prompt

Create a new pull request in dotnet/extensions with:

• Base branch: main
• Head branch: copilot/update-mcp-server-tool-invocation

User explicitly wants a new PR (do not attempt to update/retarget existing agent PR #7244).

Use an appropriate PR title/description derived from the branch name (update MCP server tool invocation). No additional code changes requested—just open the PR.

This pull request was created from Copilot chat.

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[Copilot]

Pull request overview

This PR simplifies the MCP server tool invocation approval mechanism by consolidating approval types. Instead of having separate McpServerToolApprovalRequestContent and McpServerToolApprovalResponseContent classes, it makes McpServerToolCallContent and McpServerToolResultContent inherit from FunctionCallContent and FunctionResultContent respectively, and reuses the existing FunctionApprovalRequestContent and FunctionApprovalResponseContent for MCP approvals.

Changes:

• Removed McpServerToolApprovalRequestContent and McpServerToolApprovalResponseContent classes
• Made McpServerToolCallContent extend FunctionCallContent and McpServerToolResultContent extend FunctionResultContent
• Added InvocationRequired property to FunctionCallContent (defaults to true, set to false for MCP tools)
• Updated OpenAI integration and tests to work with the unified approval model
• Added API compatibility suppressions for breaking changes

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
McpServerToolApprovalRequestContent.cs	Deleted - approval now handled through FunctionApprovalRequestContent
McpServerToolApprovalResponseContent.cs	Deleted - approval now handled through FunctionApprovalResponseContent
McpServerToolCallContent.cs	Now extends FunctionCallContent, inherits Name, CallId, and Arguments properties, sets InvocationRequired = false
McpServerToolResultContent.cs	Now extends FunctionResultContent, simplified to only add CallId through base constructor
FunctionCallContent.cs	Added InvocationRequired property and polymorphic JSON serialization for McpServerToolCallContent
FunctionResultContent.cs	Added polymorphic JSON serialization for McpServerToolResultContent
UserInputRequestContent.cs	Removed McpServerToolApprovalRequestContent from JSON derived types
UserInputResponseContent.cs	Removed McpServerToolApprovalResponseContent from JSON derived types
AIContent.cs	Updated comments to reflect removed types
OpenAIResponsesChatClient.cs	Updated to create FunctionApprovalRequestContent wrapping McpServerToolCallContent instead of separate MCP approval types, updated error handling to use Result property
OpenAIJsonContext.cs	Removed IReadOnlyDictionary<string, object?> serialization (now uses IDictionary)
AIJsonUtilities.Defaults.cs	Removed MCP approval types from JSON serialization registration
FunctionInvokingChatClient.cs	Updated approval filtering to check InvocationRequired property on function calls
CompatibilitySuppressions.xml	Added suppressions for removed types and changed properties across all target frameworks
Test files	Updated to use new API, added tests for mixed MCP/function approval scenarios, fixed namespace

[stephentoub]

@copilot please revise the PR summary based on the current state of the PR

[Copilot]

@copilot please revise the PR summary based on the current state of the PR

Updated the PR summary to accurately reflect the current state of the PR. The summary now correctly describes that McpServerToolCallContent and McpServerToolResultContent extend FunctionCallContent and FunctionResultContent respectively, and that InvocationRequired is only on FunctionCallContent (not FunctionResultContent).

[Copilot]

Pull request overview

Copilot reviewed 26 out of 26 changed files in this pull request and generated no new comments.

[stephentoub]

This direction makes sense to me.

[Copilot]

@copilot address documentation feedback.

Addressed in d0a56eb. Updated documentation for:

• FunctionApprovalRequestContent.requestId to note it's typically not the same as the function call ID
• McpServerToolCallContent remarks to explain it's informational only, provided as part of approval requests or as information about tools invoked elsewhere
• HostedMcpServerTool.Headers to mention it can be used for authorization tokens

[Copilot]

Pull request overview

Copilot reviewed 49 out of 49 changed files in this pull request and generated 4 comments.

[jozkee]

@copilot

[Copilot]

@copilot

Applied all three documentation suggestions in f9e7e0e:

• Updated HostedMcpServerTool.Headers remarks
• Updated FunctionApprovalRequestContent.requestId parameter docs with link to FunctionCallContent.CallId
• Updated McpServerToolCallContent remarks

[stephentoub]

Please double-check that this all works well with Agent Framework.

[jozkee]

Built local nugets for MEAI.Abstractions and MEAI.OpenAI, cloned af repo, ran dotnet built and dotnet test consuming these local versions. Aside from source braking changes and few tests' adjustments, seems like things will keep working in agent-framework.