[Akshay Sonawane (apsonawane)]

Summary

Make the C# RankingSession.RankAsync and DecisionSession.DecideAsync helpers safe to consume from Native AOT applications.

Problem

Predictive DTOs were registered in the SDK's shared JsonSerializationContext, which also contains Betalgo OpenAI types. Referencing the typed predictive helpers rooted that full context and caused Native AOT consumers to fail with Betalgo MessageConverter IL2026/IL3050 diagnostics.

This blocks direct typed-session use in microsoft/foundry-local-cli#73.

Changes

• Move ranking and decision DTO registrations into a dedicated source-generated NonGenerativeJsonSerializationContext.
• Point RankingSession and DecisionSession at the isolated context.
• Keep existing OpenAI serialization behavior unchanged.
• Reduce ranking result validation allocations by replacing per-response hash sets and index-string allocations.
• Store decision snapshots as value types and validate answer keys in one pass.

Validation

• C# SDK builds for net8.0, net9.0, and netstandard2.0.
• Predictive session tests pass.
• A local ranking/decision Native AOT consumer publish completes without IL2026, IL3050, Betalgo IL2104, or IL3053 warnings.

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Project	Deployment	Actions	Updated
foundry-local	Ready	Preview	Nov 10, 2026 7:32am UTC

[Copilot]

🟡 Changes recommended

The sample publish overwrites the net8.0 SDK assembly without the required version properties, causing the subsequent pack step to include incorrect version metadata despite the earlier version check.

1 open issue

• Publish rebuild overwrites net8.0 assembly version metadata · New

What changed in this PR

This PR isolates predictive-session JSON serialization from OpenAI types so C# applications can use typed ranking and decision helpers with Native AOT.

Changes:

• Move predictive DTO registrations into a dedicated source-generated context and update both session helpers.
• Replace reflection-based JSON creation in the example and enable Native AOT with selected diagnostics treated as errors.
• Add a CI Native AOT publish check for the example.

File	Description
sdk_v2/​cs/​src/​RankingSession.cs	Use the isolated predictive serialization context.
sdk_v2/​cs/​src/​Detail/​NonGenerativeJsonSerializationContext.cs	Define source-generated metadata for predictive DTOs.
sdk_v2/​cs/​src/​Detail/​JsonSerializationContext.cs	Remove predictive registrations from the shared context.
sdk_v2/​cs/​src/​DecisionSession.cs	Use the isolated predictive serialization context.
sdk_v2/​cs/​examples/​RankingAndDecision/​RankingAndDecision.csproj	Enable Native AOT and diagnostic enforcement.
sdk_v2/​cs/​examples/​RankingAndDecision/​Program.cs	Create JSON values without reflection-based serialization.
.pipelines/​templates/​steps-build-cs.yml	Publish the predictive example with Native AOT in CI.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues are reported for the predictive-session serialization isolation and validation changes.

No open issues 🎉

1 resolved since last review

• Publish rebuild overwrites net8.0 assembly version metadata

_{Review effort: Balanced}