Update .NET 10→11 migration skill for Preview 2 and 3

[danmoseley]

Summary

Updates the migrate-dotnet10-to-dotnet11 skill to cover breaking changes through .NET 11 Preview 3 (previously Preview 1 only).

Changes

Reference files — 15 new breaking changes added:

• core-libraries: BackgroundService exceptions stop host, ZipArchive CRC32 validation, TarWriter HardLink, Zstandard APIs in-box
• cryptography: AIA certificate downloads disabled by default
• efcore: Cosmos empty collections, MigrationsNotFound throws, Tools/Design dependency removed, EFOptimizeContext removed, SqlVector excluded, SqlClient 7.0 Entra auth, SQLitePCLRaw encryption bundles removed
• runtime-jit: NativeAOT lib prefix on Unix
• sdk-msbuild: NETSDK1235 warning, --self-contained parsing fix
• aspnetcore (new file): OpenAPI v3/Microsoft.OpenApi breaking changes, Blazor Virtualize OverscanCount 3→15

SKILL.md — Updated frontmatter (P1→P3), Step 1 assessment checklist, Step 3 code patterns, Step 4 behavioral changes, Step 5 global.json version, Step 6 verification items, reference tables.

Evals — 4 new scenarios: BackgroundService+ZipCRC32, EF Core SqlClient+Design, ASP.NET Core OpenAPI+Blazor, mTLS AIA certificates.

known-domains.txt — Added \github.com/dotnet/aspnetcore.

Validation

• ✅ skill-validator check passes (0 errors, 3465 BPE tokens)
• ✅ markdownlint — no new regressions
• ✅ All referenced GitHub URLs return HTTP 200

[danmoseley]

/evaluate

[Copilot]

Pull request overview

Updates the migrate-dotnet10-to-dotnet11 skill content to cover additional .NET 11 breaking changes through Preview 3, including new reference documentation and expanded evaluation scenarios.

Changes:

• Expanded SKILL.md guidance (assessment checklist, breaking-change patterns, verification items) and updated Preview 3 SDK pin example.
• Added/updated reference documents for new breaking changes (ASP.NET Core OpenAPI/Microsoft.OpenApi v3, BackgroundService host-stop behavior, ZipArchive CRC32 validation, EF Core/SqlClient, AIA downloads, NativeAOT lib prefix, etc.).
• Added 4 new eval scenarios and updated known external domains to allow new reference URLs.

Show a summary per file

File	Description
tests/dotnet-upgrade/migrate-dotnet10-to-dotnet11/eval.vally.yaml	Adds new evaluation stimuli for Preview 2/3 breaking changes (worker services, EF Core, ASP.NET Core, mTLS/AIA).
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/SKILL.md	Updates skill instructions/checklists and reference loading table for Preview 3 coverage.
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/sdk-msbuild-dotnet10to11.md	Documents new SDK/MSBuild/CLI breaking changes (NETSDK1235, --self-contained parsing).
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/runtime-jit-dotnet10to11.md	Adds NativeAOT Unix lib prefix output change.
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/efcore-dotnet10to11.md	Adds EF Core Preview 3 breaking changes (migrations behavior, dependencies, SqlClient, SQLite bundle removal, etc.).
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/cryptography-dotnet10to11.md	Adds AIA intermediate cert download behavior change documentation.
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/core-libraries-dotnet10to11.md	Adds core library breaking changes (CRC32 validation, BackgroundService behavior, tar hardlinks, Zstandard in-box).
plugins/dotnet-upgrade/skills/migrate-dotnet10-to-dotnet11/references/aspnetcore-dotnet10to11.md	New ASP.NET Core reference doc (OpenAPI.NET v3 upgrade, Blazor Virtualize default change).
eng/known-domains.txt	Allows new GitHub repo domain prefix used by the added ASP.NET Core reference sources.

Copilot's findings

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Comments suppressed due to low confidence (1)

tests/dotnet-upgrade/migrate-dotnet10-to-dotnet11/eval.vally.yaml:329

• The output-matches regex (Virtualize|OverscanCount|3|15) is overly permissive: it will pass if the model mentions any "3" (e.g., "Preview 3") or any other incidental number, without actually addressing the Virtualize OverscanCount change. Tighten this check by requiring Virtualize/OverscanCount and the new default value (15) in the same regex (e.g., via lookaheads) or by splitting into multiple, more specific output-matches graders.

          pattern: (OpenApi|Microsoft\.OpenApi|v3|3\.2|upgrade)
      - type: output-matches
        config:
          pattern: (Virtualize|OverscanCount|3|15)
      - type: prompt

• Files reviewed: 9/9 changed files
• Comments generated: 3

[github-actions]

Skill Coverage Report

	Plugin	Skill	Covered	Coverage
✅	dotnet-upgrade	migrate-dotnet10-to-dotnet11	5/6	83.3%

Uncovered: dotnet-upgrade/migrate-dotnet10-to-dotnet11

• [WorkflowStep] Step 5: Update infrastructure (line 169)

[github-actions]

Skill Validation Results

Skill	Scenario	Quality	Skills Loaded	Overfit	Verdict
migrate-dotnet10-to-dotnet11	Console app with compression and TAR operations	4.0/5 ⏰ → 4.7/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, view	✅ 0.04	✅ [1]
migrate-dotnet10-to-dotnet11	C# 15 compiler breaking changes — Span safe-context, nameof, with()	3.0/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, report_intent, view	✅ 0.04	✅
migrate-dotnet10-to-dotnet11	EF Core app with Cosmos DB provider using sync APIs	4.0/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, report_intent, view / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.04	❌ [2]
migrate-dotnet10-to-dotnet11	Deployment to older hardware with minimum requirement changes	3.7/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.04	✅ [3]
migrate-dotnet10-to-dotnet11	Cryptography app using DSA on macOS	3.7/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.04	❌ [4]
migrate-dotnet10-to-dotnet11	Basic TFM update with Docker and global.json	3.7/5 → 4.7/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill	✅ 0.04	✅ [5]
migrate-dotnet10-to-dotnet11	C# 15 dynamic operator and ref readonly delegate issues	2.3/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, report_intent, view / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.04	✅

[1] ⚠️ High run-to-run variance (CV=12.75) — consider re-running with --runs 5
[2] ⚠️ High run-to-run variance (CV=0.86) — consider re-running with --runs 5. (Isolated) Quality improved but weighted score is -30.2% due to: judgment, quality, tokens (13145 → 49433), tool calls (0 → 4)
[3] ⚠️ High run-to-run variance (CV=0.50) — consider re-running with --runs 5
[4] ⚠️ High run-to-run variance (CV=8.55) — consider re-running with --runs 5. (Isolated) Quality improved but weighted score is -24.2% due to: judgment, quality, tokens (13279 → 47780), tool calls (0 → 4)
[5] ⚠️ High run-to-run variance (CV=1.08) — consider re-running with --runs 5

⏰ timeout — run(s) hit the (180s) scenario timeout limit; scoring may be impacted by aborting model execution before it could produce its full output (increase via timeout in eval.yaml)

Model: claude-opus-4.6 | Judge: claude-opus-4.6

🔍 Full Results - additional metrics and failure investigation steps

▶ Sessions Visualisation -- interactive replay of all evaluation sessions

[Copilot]

Copilot's findings

• Files reviewed: 9/9 changed files
• Comments generated: 2

[danmoseley]

/evaluate

[github-actions]

Skill Validation Results

Skill	Scenario	Quality	Skills Loaded	Overfit	Verdict
migrate-dotnet10-to-dotnet11	Console app with compression and TAR operations	5.0/5 → 4.3/5 🔴	✅ migrate-dotnet10-to-dotnet11; tools: skill, view	✅ 0.05	❌
migrate-dotnet10-to-dotnet11	C# 15 compiler breaking changes — Span safe-context, nameof, with()	3.3/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, report_intent, view / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.05	✅
migrate-dotnet10-to-dotnet11	EF Core app with Cosmos DB provider using sync APIs	4.3/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, bash, view / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.05	❌ [1]
migrate-dotnet10-to-dotnet11	Deployment to older hardware with minimum requirement changes	2.3/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.05	✅
migrate-dotnet10-to-dotnet11	Cryptography app using DSA on macOS	3.3/5 → 5.0/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill, report_intent, view / ✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.05	❌ [2]
migrate-dotnet10-to-dotnet11	Basic TFM update with Docker and global.json	3.7/5 → 4.3/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: skill	✅ 0.05	✅ [3]
migrate-dotnet10-to-dotnet11	C# 15 dynamic operator and ref readonly delegate issues	2.0/5 ⏰ → 4.7/5 🟢	✅ migrate-dotnet10-to-dotnet11; tools: report_intent, skill, view	✅ 0.05	✅

[1] (Isolated) Quality improved but weighted score is -12.4% due to: quality, tokens (13296 → 48909), tool calls (0 → 4)
[2] ⚠️ High run-to-run variance (CV=1.60) — consider re-running with --runs 5. (Isolated) Quality improved but weighted score is -29.1% due to: judgment, quality, tokens (13777 → 47651), tool calls (0 → 4)
[3] ⚠️ High run-to-run variance (CV=1.71) — consider re-running with --runs 5

⏰ timeout — run(s) hit the (180s) scenario timeout limit; scoring may be impacted by aborting model execution before it could produce its full output (increase via timeout in eval.yaml)

Model: claude-opus-4.6 | Judge: claude-opus-4.6

🔍 Full Results - additional metrics and failure investigation steps

▶ Sessions Visualisation -- interactive replay of all evaluation sessions