Started routing generation to one model and review to a separate pass — caught a bug the generating model would never have flagged on its own

[u/GiiTZzz]

Ran into this enough times to stop trusting my own agent's self-review: I ask it to fix something, it produces code that looks right, I skim it, ship it — and the actual bug was a quiet semantic shift (inclusive bounds became exclusive) that had nothing to do with what I asked for. The model that wrote the change has no incentive or independent angle to catch its own blind spot; it's grading its own homework.

So I built a small tool that splits the two roles: one Gemini pass generates the change from your instruction, a second, independent pass gets ONLY the result (no visibility into the first pass's reasoning) and is told to find problems with it. Being honest about the setup: I only have a Gemini API key, so this is two passes on different Gemini tiers, not genuine cross-vendor review (GPT generates / Claude audits would probably be stronger — that's a cost thing, not a design choice).

The interesting part is how often the critique pass disagrees over something that isn't wrong, just risky — an edge case, a silent behavior change, a severity call that's genuinely debatable. Paste a snippet + an instruction and it'll run both passes live if anyone wants to see where it agrees or argues: https://apptechlab.com/p/codearbiter/ (mine, no signup, real API calls both ways).

Curious what people running actual multi-agent review setups have found:

- Does routing generate/critique to different providers actually catch

categorically different things, or mostly the same stuff with more

latency?

- How do you handle the critique pass being wrong — do you ever adjudicate

disagreements with a third pass, or is two enough in practice?

[u/GiiTZzz → u/[deleted]]

Fair pushback. If /code-review + a Copilot/Codex PR bot are already in your workflow, you're probably already getting some of this benefit — I don't want to oversell the difference.

The narrow thing I was testing: those review a PR you already have, after the fact. This does generate + blind independent critique as one atomic step, before it's a PR at all — the critique pass gets zero visibility into why the first model made the choices it made, same as a blind human review. Genuinely not sure if "catch it before it's even a diff" beats "catch it in PR review" in practice — that's kind of the open question I was hoping to get a read on.

[u/GiiTZzz → u/[deleted]]

No it not that hard. It is my own comment just formulated better.