[reference-impl-sync] Reference Implementation sync: 14 new commits (2026-05-18)

[github-actions]

Automated Reference Implementation Sync

There are 14 new commits in the official Copilot SDK since the last merge.

• Last merged commit: e20f5bef125860accb30c60d1b35109371a77f16
• Reference Implementation HEAD: f6c1adf8329ad4206e5ed2e8d12fb8082bc841a2

Recent reference implementation commits

f6c1adf Fix sub-agent hook propagation: expose sessionId on hook inputs (#1290)
8410ed2 Add cloud session config support (#1306)
62fabf6 Add .NET CopilotTool helper (#1321)
4367275 Fix some argument validation in C# (#1322)
f445b5c Add netstandard and net10 targets to C# SDK (#1320)
25b15be Honor preinstalled CLI path in .NET MSBuild targets (#921) (#1318)
a623d07 Harden permission-reject E2E tests across all SDKs (#1194) (#1317)
fc11032 Stabilize compaction E2E tests (#1314)
bc0f1c4 Consolidate ask_user E2E snapshots into single canonical folder (#1311)
31ea472 Fix Python session.send docs examples (#1312)
59f0981 Fix Python Quick Start example to compile with current SDK (#1310)
d0eb531 feat: add model field to CustomAgentConfig across all SDKs (#1309)
38f38ff Update `@github/copilot` to 1.0.49-1 (#1307)
215676e Update `@github/copilot` to 1.0.49-0 (#1305)

Instructions

You MUST follow these steps in order. Do NOT improvise or skip scripts.

1. ✅✅Read .github/prompts/agentic-merge-reference-impl.prompt.md in full before starting✅✅

❌❌Do NOT clone the reference implementation manually — the start script does this.❌❌
❌❌Do NOT update .lastmerge manually — the finish script does this.❌❌
❌❌Do NOT skip the finish script — it syncs codegen versions and updates .lastmerge.❌❌

Generated by Reference Implementation Sync · ● 249.6K · ◷

• expires on May 24, 2026, 5:13 PM UTC