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Approach 2: MCP/Approvals/Tool Contents stabilization#7299

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jozkee wants to merge 17 commits intodotnet:mainfrom
jozkee:tool_approval_content2
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Approach 2: MCP/Approvals/Tool Contents stabilization#7299
jozkee wants to merge 17 commits intodotnet:mainfrom
jozkee:tool_approval_content2

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@jozkee jozkee commented Feb 13, 2026 •
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Alternative to #7245.

Benefits:

  • Approval extensibility: The MCP approval pattern is likely to expand to other hosted tools and the hierarchy needs to support that.
  • Don't leak Function-specific members, today only applies to Exception.
  • Keeps doors open:
    • MCP content can move under FunctionCallContent later.
    • Base Hosted content for MCP, CodeInt and ImageGen (mutually exclusive with FCC move, though).

Cost:

  • Reconcile Outputs with Result (can be deferred, non-breaking in the future).
  • Unify CallId nullability and name
    • ImageGen uses ImageId
    • Both ImageGen and CodeInterpreter are nullable get; set; but this can be changed to non-nullable get-only like functions.

@jozkee jozkee requested a review from a team as a code owner February 13, 2026 18:12
@github-actions github-actions bot added the area-ai Microsoft.Extensions.AI libraries label Feb 13, 2026
Copilot AI reviewed Feb 13, 2026
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Pull request overview

This PR stabilizes MCP/tool-calling and approval-related content types across the Microsoft.Extensions.AI stack, updating both runtime code and tests to use the new ToolCallContent / ToolResultContent and ToolApproval* abstractions (and related serialization/telemetry plumbing).

Changes:

  • Introduces/standardizes new base content types (ToolCallContent, ToolResultContent, InputRequestContent, InputResponseContent) and migrates approvals to ToolApprovalRequestContent / ToolApprovalResponseContent.
  • Updates OpenAI Responses conversion + OpenTelemetry serialization to the new content model (e.g., Outputs vs Output, MCP call Name vs ToolName, image/code tool call IDs).
  • Refreshes and expands test coverage for the new content hierarchy, serialization roundtrips, and mixed MCP/function approval flows.

Reviewed changes

Copilot reviewed 70 out of 70 changed files in this pull request and generated no comments.

Show a summary per file
File Description
test/Libraries/Microsoft.Extensions.AI.Tests/ChatReduction/SummarizingChatReducerTests.cs Updates reducer tests to use InputRequestContent/InputResponseContent test types.
test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs Updates serialization expectations for tool call/result + approvals; aligns with constructor-based IDs and Outputs.
test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/ImageGeneratingChatClientTests.cs Switches image tool ID assertions from ImageId to CallId.
test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientTests.cs Updates approval assertions to ToolApprovalRequestContent/ToolApprovalResponseContent and ToolCall.
test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/FunctionInvokingChatClientApprovalsTests.cs Adds mixed MCP/function approval scenarios; updates approval types and introduces input cloning helper for streaming/non-streaming parity.
test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientTests.cs Updates MCP naming/output/approval assertions and adds error + bearer-token extraction tests.
test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIResponseClientIntegrationTests.cs Updates integration tests to use ToolApprovalRequestContent and CreateResponse; switches MCP tool name/output properties.
test/Libraries/Microsoft.Extensions.AI.OpenAI.Tests/OpenAIConversionTests.cs Updates MCP tool auth/header tests; expands streaming update conversion coverage (including approval correlation behavior).
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Tools/HostedMcpServerToolTests.cs Adjusts tests for nullable Headers and removal of AuthorizationToken.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs Updates source-gen context registrations for new polymorphic base types and tool call/result arrays.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs Removes tests for deprecated UserInputResponseContent.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs Removes tests for deprecated UserInputRequestContent.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ToolResultContentTests.cs Adds roundtrip serialization coverage for ToolResultContent derived types.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ToolCallContentTests.cs Adds roundtrip serialization coverage for ToolCallContent derived types.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ToolApprovalResponseContentTests.cs Adds constructor validation + serialization roundtrip tests for ToolApprovalResponseContent.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ToolApprovalRequestContentTests.cs Adds constructor validation + response factory + serialization roundtrip tests for ToolApprovalRequestContent.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.cs Updates MCP result content to Outputs and validates polymorphic roundtrips.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolCallContentTests.cs Renames MCP call ToolName→Name, Arguments mutability update, and adds serialization roundtrip.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/InputResponseContentTests.cs Adds base input-response type validation + derived serialization tests.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/InputRequestContentTests.cs Adds base input-request type validation + derived serialization tests.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ImageGenerationToolResultContentTests.cs Moves to ctor-based CallId and removes ImageId usage.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/ImageGenerationToolCallContentTests.cs Moves to ctor-based CallId and removes ImageId usage.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionResultContentTests.cs Adds serialization roundtrip tests for ToolResultContent/AIContent polymorphism.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionCallContentTests.cs Adds serialization roundtrip tests for ToolCallContent/AIContent polymorphism.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs Removes deprecated FunctionApprovalResponseContent tests.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs Removes deprecated FunctionApprovalRequestContent tests.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/CodeInterpreterToolResultContentTests.cs Moves to ctor-based CallId and removes settable CallId.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/CodeInterpreterToolCallContentTests.cs Moves to ctor-based CallId and removes settable CallId.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/AIContentTests.cs Updates derived-type list and strengthens per-element polymorphic roundtrip checks.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/ChatCompletion/ChatResponseUpdateExtensionsTests.cs Updates coalescing tests to use CallId and ctor-based tool result creation.
test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/AssertExtensions.cs Extends message comparison helpers to handle tool approvals uniformly across tool call types.
src/Libraries/Microsoft.Extensions.AI/ChatReduction/SummarizingChatReducer.cs Updates “tool-related content” detection to include InputRequestContent/InputResponseContent.
src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs Updates OTel payload serialization for renamed properties (Name, Outputs, CallId) and unified approval types.
src/Libraries/Microsoft.Extensions.AI/ChatCompletion/ImageGeneratingChatClient.cs Switches to ctor-based image tool call/result creation with CallId.
src/Libraries/Microsoft.Extensions.AI/ChatCompletion/FunctionInvokingChatClient.cs Migrates approvals to ToolApproval* with composed request IDs; updates request/response processing logic.
src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIResponsesChatClient.cs Implements MCP approval request/response correlation in Responses conversion; updates tool call/result modeling and connector auth extraction from headers.
src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIJsonContext.cs Removes IReadOnlyDictionary<string, object?> source-gen contract in favor of IDictionary<string, object?>.
src/Libraries/Microsoft.Extensions.AI.OpenAI/OpenAIAssistantsChatClient.cs Switches code interpreter tool call/result construction to ctor-based CallId.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.cs Adds helper for registering derived types into polymorphism options.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.Defaults.cs Updates default serializer configuration to include new polymorphic bases and registers experimental tool types under ToolCallContent/ToolResultContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Tools/HostedMcpServerTool.cs Stabilizes MCP tool; removes AuthorizationToken and makes Headers nullable/settable; renames Uri ctor arg to serverAddress.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Microsoft.Extensions.AI.Abstractions.json Updates API baseline/staging to reflect stabilization and new content hierarchy.
src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolRequireSpecificApprovalMode.cs Removes experimental annotations in support of stabilization.
src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolNeverRequireApprovalMode.cs Removes experimental annotations in support of stabilization.
src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolApprovalMode.cs Removes experimental/polymorphic annotations in support of stabilization and updated serialization model.
src/Libraries/Microsoft.Extensions.AI.Abstractions/HostedMcpServerToolAlwaysRequireApprovalMode.cs Removes experimental annotations in support of stabilization.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Functions/ApprovalRequiredAIFunction.cs Removes experimental annotation (stabilizing the API).
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs Removes deprecated UserInputResponseContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs Removes deprecated UserInputRequestContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ToolResultContent.cs Introduces new ToolResultContent base type for tool results.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ToolCallContent.cs Introduces new ToolCallContent base type for tool calls.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ToolApprovalResponseContent.cs Introduces unified approval response content for tool calls.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ToolApprovalRequestContent.cs Introduces unified approval request content and response factory helper.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolResultContent.cs Updates MCP tool results to derive from ToolResultContent and renames Output→Outputs.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolCallContent.cs Updates MCP tool calls to derive from ToolCallContent, renames ToolName→Name, and updates arguments type.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalResponseContent.cs Removes deprecated MCP approval response content type.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/McpServerToolApprovalRequestContent.cs Removes deprecated MCP approval request content type.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/InputResponseContent.cs Introduces new InputResponseContent base type for input responses.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/InputRequestContent.cs Introduces new InputRequestContent base type for input requests.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ImageGenerationToolResultContent.cs Updates image result content to derive from ToolResultContent and use ctor CallId.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/ImageGenerationToolCallContent.cs Updates image call content to derive from ToolCallContent and use ctor CallId.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionResultContent.cs Updates function result content to derive from ToolResultContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionCallContent.cs Updates function call content to derive from ToolCallContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalResponseContent.cs Removes deprecated function approval response content type.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/FunctionApprovalRequestContent.cs Removes deprecated function approval request content type.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/CodeInterpreterToolResultContent.cs Updates code interpreter result content to derive from ToolResultContent and use ctor CallId.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/CodeInterpreterToolCallContent.cs Updates code interpreter call content to derive from ToolCallContent and use ctor CallId.
src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIContent.cs Registers stabilized tool/approval content types as derived types of AIContent.
src/Libraries/Microsoft.Extensions.AI.Abstractions/ChatCompletion/ChatResponseExtensions.cs Updates content coalescing logic for ctor-based tool content and CallId usage.

@jozkee jozkee force-pushed the tool_approval_content2 branch from 1111f09 to 5343bb0 Compare February 18, 2026 04:18
ericstj
ericstj approved these changes Feb 18, 2026
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This looks good to me - your call on the output abstraction. At least think through how you might do it compatibly.

@jozkee jozkee mentioned this pull request Feb 25, 2026
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stephentoub
stephentoub reviewed Mar 2, 2026
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Looks pretty good.

jozkee added 5 commits March 2, 2026 18:27
@jozkee
* Add [JsonDerivedType] on AIContent for ToolCallContent, ToolResultC…
6a29d0c 
…ontent, InputRequestContent, and InputResponseContent; remove redundant [JsonSerializable] entries from AIJsonUtilities.Defaults

* Consolidate AddDerivedContentType into AddAIContentType with baseType param
* Make ToolCallContent and ToolResultContent constructors public
@jozkee
* Map WebSearch/FileSearch/ComputerCall/ComputerCallOutput ResponseIt…
d2bed82 
…ems to ToolCallContent/ToolResultContent in OpenAIResponsesChatClient (both non-streaming and streaming paths)

* Store ToolApprovalRequestContent in mcpApprovalRequests dictionary instead of McpToolCallApprovalRequestItem, reusing ToolCall on correlation
@jozkee
Documentation feedback
786e8f7
@jozkee
Merge remote-tracking branch 'upstream/main' into tool_approval_content2
890c5ec
@jozkee
Fix cref
e4a1364
@stephentoub stephentoub mentioned this pull request Mar 3, 2026
Closed
@jozkee jozkee enabled auto-merge (squash) March 4, 2026 00:18
@jozkee jozkee disabled auto-merge March 4, 2026 00:29
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@ericstj ericstj ericstj approved these changes

@halter73 halter73 Awaiting requested review from halter73

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