Debugging Black Ops 2 with ChatGPT
I asked ChatGPT to investigate why Local Zombies would not start in Xenia. Its experimental session changes reached TranZit and five DLC maps. The tests identified missing emulator behavior; a finished fix is still pending.
- Target
- Offline Zombies + owned DLC
- Runtime
- Native Linux Xenia Canary
- Current stage
- Diagnostic gameplay tests
- Finished fix
- Not yet released
Empty Local Zombies lobby
My request was to investigate why offline Zombies would not start in Xenia. The Local lobby had no player listed, and Start Match was disabled. ChatGPT set up a separate test copy and tried a fresh profile, then built unmodified Xenia source. Both reproduced the same failure, so creating another profile had not solved it.
The agent compared emulator logs with the game’s loaded code. Xenia reported successful session creation while leaving data the game expected unset. ChatGPT added diagnostic changes one at a time. Supplying the missing identity exposed another failure, followed by failures when the game tried to leave or modify a session.
What ChatGPT reached in the game
ChatGPT’s combined diagnostic build loaded TranZit twice. It sent controller inputs and checked screenshots for movement and firing. The ammunition count changed from 8/32 to 7/32. The first player died while the agent inspected its output.
Later tests reached Mob of the Dead, Nuketown, Origins, Buried and Die Rise. The agent also corrected a controller mapping that had prevented Start from opening the pause menu. These are automated checks with reviewed captures; I have not accepted BO2 as a finished playable release.
Some diagnostic changes simply tell the game an operation succeeded. That helped locate the missing behavior, but the real session creation, updates and cleanup still need implementation. ChatGPT retained the experimental build separately from the proposed Vulkan fix. No emulator patch has been submitted upstream.
Vulkan startup crash
ChatGPT also investigated a separate startup crash. A comparison crashed once in four attempts without a Vulkan layout lock. With the lock, all four attempts reached the menu. That suggests concurrent access to the layout data may be involved, but more runs are needed. Windows Xenia under Proton also failed at startup; the current BO2 tests use native Linux Xenia.
BO2 test coverage
Test results
- The empty lobby reproduced with two profiles and the clean source build.
- Two diagnostic TranZit spawns with movement and firing.
- Short spawns with input on all five installed Zombies DLC maps; pause and return-to-lobby checked on Mob of the Dead.
Remaining tests and fixes
- Implement offline session handling without the diagnostic shortcuts.
- Repeat menu transitions and launches; investigate the separate intermittent startup stall.
- Test longer matches and check for new failures.