Azure/azure-sdk-for-net Azure.AI.AgentServer.Core_1.0.0-beta.21

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1.0.0-beta.21 (2026-04-14)

This is a major architectural rewrite. The package has been redesigned as a lightweight hosting
foundation. Protocol implementations that were previously bundled in this package have moved to
dedicated protocol packages (Azure.AI.AgentServer.Responses, Azure.AI.AgentServer.Invocations).
See the Migration Guide
for upgrading from earlier beta versions.

Breaking Changes

• Package split: All Responses API protocol types (models, invocation handlers, SSE streaming) have moved to Azure.AI.AgentServer.Responses. All Invocations protocol types have moved to Azure.AI.AgentServer.Invocations. This package now contains only the shared hosting foundation.
• Dependency removed: Azure.AI.AgentServer.Contracts is no longer required. The generated OpenAI Responses API models are now built into Azure.AI.AgentServer.Responses.
• Dependencies removed: Azure.AI.Projects, Microsoft.Agents.AI.*, and ModelContextProtocol packages are no longer dependencies of this package.
• API redesigned: The old IAgentInvocation / AgentInvocationContext / CreateResponseRequest API surface has been replaced with AgentHostBuilder and protocol-specific handler abstractions (ResponseHandler in Responses, InvocationHandler in Invocations).
• Namespace changed: Code that previously used Azure.AI.AgentServer.Core.Responses.* or Azure.AI.AgentServer.Contracts.* namespaces must switch to Azure.AI.AgentServer.Responses.

Features Added

• Library-owned hosting foundation via AgentHostBuilder (composable builder pattern).
• OpenTelemetry integration with Azure.Monitor.OpenTelemetry.AspNetCore and OTLP exporter support.
• Health endpoint at /readiness for liveness and readiness probes.
• Multi-protocol composition via AgentHostBuilder.RegisterProtocol(). Protocol packages provide extension methods (e.g., AddResponses<T>(), AddInvocations<T>()) built on top of this API.
• Graceful shutdown with configurable drain period.
• Server user-agent x-platform-server header on every response with SDK version info.
• ServerUserAgentRegistry for protocol packages to register user-agent identity segments.
• AddAgentServerUserAgent() and UseAgentServerUserAgent() extensions for standalone (Tier 3) setups.
• FoundryEnvironment for Azure AI Foundry platform variable resolution.
• Distributed tracing context propagation via request ID baggage.

Previous versions (prior to 1.0.0-beta.21)

Versions prior to 1.0.0-beta.21 used a monolithic architecture where Azure.AI.AgentServer.Core
bundled protocol logic and depended on Azure.AI.AgentServer.Contracts for generated models.
These versions are superseded by the new 3-package architecture. See the
Migration Guide
for details.