[reference-impl-sync] Reference Implementation sync: 9 new commits (2026-05-17)

[github-actions]

Automated Reference Implementation Sync

There are 9 new commits in the official Copilot SDK since the last merge.

• Last merged commit: e20f5bef125860accb30c60d1b35109371a77f16
• Reference Implementation HEAD: 25b15be86c443c776bc2ab057c698a2ef0b67f35

Recent reference implementation commits

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 · ● 282.5K · ◷

• expires on May 23, 2026, 4:33 PM UTC

[github-actions]

Superseded by a newer reference implementation sync check.