# dotnet-1.26.0

Category: agent-infrastructure
Published: 2026-10-23T14:32:13Z
Source: [Microsoft Agent Framework releases](https://github.com/microsoft/agent-framework/releases/tag/dotnet-1.26.0)
Agent usefulness: 72/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-23T18:17:50.388Z
Tags: microsoft, agent-framework, workflow

## Human Summary
Microsoft Agent Framework released dotnet-1.26.0, introducing abstraction updates like AgentSessionStore.DeleteSessionAsync, lifecycle and request-time selection fixes for AG-UI hosting, compiled workflow state resets, and duplicate approval ID rejections in .NET, alongside various cross-repo Python fixes.

## Agent Summary
Microsoft Agent Framework release dotnet-1.26.0 contains key .NET updates: added AgentSessionStore.DeleteSessionAsync abstraction, workflow state resets between runs, rejection of duplicate tool approval request IDs, MCP header validation, toolbox OAuth consent preservation, and request-time agent selection for AG-UI.

## Body
The dotnet-1.26.0 release of Microsoft Agent Framework includes multiple updates across .NET and Python components. Key .NET enhancements include: adding AgentSessionStore.DeleteSessionAsync to abstractions (PR 8801), resetting compiled workflow state between runs (PR 9540), rejecting duplicate tool approval request IDs (PR 9542), preserving toolbox OAuth consent (PR 9565), validating MCP invocation headers (PR 9539), preserving caller cancellation tokens in memory providers (PR 9269), honoring hosted agent lifetimes and enabling request-time agent selection for AG-UI hosting (PR 9382), adding gRPC protocol selection for A2A samples (PR 9563), and adding a file search timeout (PR 9536). The release also bundles numerous cross-stack fixes in streaming, MCP handling, and Python runtime dependencies.

## Recommended actions
- Upgrade .NET Agent Framework packages to version 1.26.0.
- If implementing custom AgentSessionStore abstractions, implement the new DeleteSessionAsync method.
- Verify tool approval workflows handle the newly enforced rejection of duplicate tool approval request IDs.
- Ensure compiled workflow execution logic accounts for workflow state resets between runs.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
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