Repro: ResumeSessionWithTools BYOK Issue

Standalone reproduction of the issue where resuming a session with new tools fails when using BYOK (Bring Your Own Key) with OpenAI, but works with Copilot auth.

Issue

When using BYOK with OpenAI:

• Resume session with new tool registration
• Ask AI to use the new tool
• Tool is never invoked

With Copilot auth: PASS (20s) With BYOK/OpenAI: FAIL (tool never called)

Build

cd tests/repro
cmake -B build -G "Visual Studio 17 2022" -A x64
cmake --build build --config Release

Run

Without BYOK (uses Copilot auth):

build\Release\repro_resume_with_tools.exe

With BYOK:

copy byok.env.example byok.env
# Edit byok.env with your OpenAI credentials
build\Release\repro_resume_with_tools.exe

Expected Output

With Copilot:

[!] Tool invoked with key: ALPHA
[PASS] Tool was invoked correctly!

With BYOK/OpenAI:

[FAIL] Tool was NOT invoked - this is the BYOK/OpenAI limitation