What did I do?
Ran just test-python (as a developer) as mentioned in CONTRIBUTING.md
What did I observe?
Some of my premium requests were consumed from my copilot plan
Evidence (Video)

Effect
Opensource contributors will lose their premium requests unintendedly.
There is no entry for this session in copilot --resume too (should we fix this?). So, they may not even realise.
Root cause
test_session.py uses a prompt that is not there in the harness. It misses a string "note this", compared to other language SDKs.
Probably Introduced in Commit
a4ffbf0