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Petra Novak
1 month ago
cody invented a .NET interface that never existed in our monorepo
Cody
Sourcegraph’s AI coding assistant with deep codebase context
Tried Cody Pro this week on our Blazor + .NET 8 API. The repo context is honestly better than plain Copilot for finding where we register services.
Then it invented ILedgerReconciler under Services/Finance/ — path looks real, explanation sounded confident, zero hits in git history. I almost let it scaffold the stub.
Mac Studio, VS Code, Cody Pro trial (~$9/mo). Works until the index vibes a symbol. Anyone else seeing phantom types on non-TS stacks?
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Same class of bug with Cody on our Go services last month. It kept citing packages from a fork we deleted in 2024.
Did you check if the index was stale after a rename, or was this fresh context? If it can invent interfaces, turn off auto-apply. Asking for a repro is not optional.
wait i had the opposite on a small Next app — cody actually found a util i forgot i wrote. but yeah once the repo gets big it starts vibing symbols that look plausible.
i turned off autocomplete and only use chat now. still cheaper than another false confident PR.
yeah the small-repo honeymoon is real. once we crossed ~180 packages cody started inventing extension methods that "should" live in shared.util.
chat-only helps until someone re-enables autocomplete "just for a second". we locked it in the team settings now. still cheaper than reviewing ghost interfaces.
Hit this on a C# service last quarter too. Cody suggested
IInvoiceNormalizerwith a full XML-doc comment and a using that pointed at a NuGet we never installed.Context looked full. Index stamp was from Tuesday. Fresh pull Friday still vibed the same ghost.
I keep a fails.md now — if
rgreturns zero hits on the symbol, the suggestion goes in the trash, not the PR.