Gemini 4 Argon vs GPT-6 Luna
Reading a 26.2K-token pull request costs $0.0524 on Gemini 4 Argon, 20× the $0.0026 it costs on GPT-6 Luna. Gemini 4 Argon is a mid-range model and GPT-6 Luna a economy one. The benchmark cannot separate their recall: Gemini 4 Argon minus GPT-6 Luna is +15 pts (95% interval 0 pts to +30 pts).
Side by side
| Figure | Gemini 4 Argon | GPT-6 Luna |
|---|---|---|
| Price tier | Mid-range | Economy |
| Bugs caughtshare of known bugs | 82% (better) | 67% |
| False alarmsper clean PR | 1.1 | 0.7 (better) |
| Cost per reviewmeasured | $0.0527 | $0.0028 (better) |
| Cost per bug caught | $0.0706 | $0.0046 (better) |
| Exact linecatches on the expected lines | 78% | 97% (better) |
| Review timemean | 99s | 29s (better) |
| Typical review calllist price | $0.0766 | $0.0038 (better) |
| Input / 1M tokens | $2.00 | $0.10 (better) |
| Output / 1M tokens | $10.00 | $0.50 (better) |
| Context window | 1M | 1.1M |
Head to head
The known bugs both were scored on, by who caught each in at least one run.
By language
| Model | All | TypeScript6 bugs | Go4 bugs | Java4 bugs | Rust4 bugs | C#3 bugs | JavaScript3 bugs | Kotlin3 bugs | PHP3 bugs | Python3 bugs | Ruby3 bugs | Swift3 bugs | C++2 bugs | C1 bug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gemini 4 Argon | 82% | 83% | 50% | 83% | 75% | 89% | 67% | 100% | 100% | 83% | 100% | 100% | 100% | 0% |
| GPT-6 Luna | 67% | 83% | 25% | 65% | 75% | 56% | 67% | 67% | 67% | 100% | 67% | 100% | 50% | 0% |
Of the 42 known bugs both were scored on, both caught 27 and neither caught 4. Gemini 4 Argon caught 9 bugs that GPT-6 Luna missed: 1 in C++, 1 in C#, 1 in Go, 1 in Java, 1 in JavaScript, 1 in Kotlin, 1 in PHP, 1 in Ruby and 1 in TypeScript. GPT-6 Luna caught 2 bugs that Gemini 4 Argon missed: 1 in JavaScript and 1 in TypeScript.
On pull requests with no known bug, Gemini 4 Argon raised 1.1 false alarms per review and GPT-6 Luna 0.7. A measured review cost $0.0527 on Gemini 4 Argon, 19× the cost of $0.0028 on GPT-6 Luna.
| Pull request | Language · kind | Gemini 4 Argon | GPT-6 Luna |
|---|---|---|---|
| dotnet/orleansfix(serialization): cap codec allocations | C# · Logic | 1/1 | 0/1 |
| ggml-org/llama.cpprpc : cache and reuse compute graphs | C++ · Security | 1/1 | 0/1 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 1/1 | 0/1 |
| sindresorhus/p-throttleAdd `weight` option | JavaScript · Logic | 1/1 | 0/1 |
| socketry/asyncBarrier wait in completion order + `Queue#close`. | Ruby · Concurrency | 1/1 | 0/1 |
| symfony/symfony[Security] Allow multiple OIDC discovery endpoints | PHP · Security | 1/1 | 0/1 |
| traefik/traefikAdd the option to define custom cipher suites for backend serversTransport | Go · API misuse | 1/1 | 0/1 |
| withastro/astroPort Go's csrf protection | TypeScript · Logic | 1/1 | 0/1 |
| jhy/jsoupStore cached child els in Attributes, not field | Java · Concurrency | 1/2 | 0/2 |
| colinhacks/zodfeat(v4): parse input containing reference cycles | TypeScript · Resource handling | 0/1 | 1/1 |
| nodejs/undicifeat: add configurable maxPayloadSize for WebSocket | JavaScript · Security | 0/1 | 1/1 |
Defects caught over all runs: a PR reviewed three times with one known bug shows 3/3 when it was caught every time.
Every bug each was scored on: Gemini 4 Argon and GPT-6 Luna.