Claude Opus 5.5 vs Gemini 4 Argon
Reading a 26.2K-token pull request costs $0.1048 on Claude Opus 5.5, 2.0× the $0.0524 it costs on Gemini 4 Argon. Claude Opus 5.5 is a frontier model and Gemini 4 Argon a mid-range one. The benchmark cannot separate their recall: Claude Opus 5.5 minus Gemini 4 Argon is +8 pts (95% interval −4 pts to +21 pts).
Side by side
| Figure | Claude Opus 5.5 | Gemini 4 Argon |
|---|---|---|
| Price tier | Frontier | Mid-range |
| Bugs caughtshare of known bugs | 90% (better) | 82% |
| False alarmsper clean PR | 1.7 | 1.1 (better) |
| Cost per reviewmeasured | $0.1525 | $0.0527 (better) |
| Cost per bug caught | $0.1921 | $0.0706 (better) |
| Exact linecatches on the expected lines | 89% (better) | 78% |
| Review timemean | 33s (better) | 99s |
| Typical review calllist price | $0.1532 | $0.0766 (better) |
| Input / 1M tokens | $4.00 | $2.00 (better) |
| Output / 1M tokens | $20.00 | $10.00 (better) |
| Context window | 1M | 1M |
- From 2026-12-01, after a scheduled reprice, the two cost the same.
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Claude Opus 5.5 | 90% | 100% | 50% | 78% | 100% | 100% | 100% | 67% | 100% | 100% | 89% | 100% | 100% | 100% |
| Gemini 4 Argon | 82% | 83% | 50% | 83% | 75% | 89% | 67% | 100% | 100% | 83% | 100% | 100% | 100% | 0% |
Of the 42 known bugs both were scored on, both caught 34 and neither caught 1. Claude Opus 5.5 caught 5 bugs that Gemini 4 Argon missed: 1 in C, 1 in Go, 1 in JavaScript, 1 in Rust and 1 in TypeScript. Gemini 4 Argon caught 2 bugs that Claude Opus 5.5 missed: 1 in Go and 1 in Kotlin.
On pull requests with no known bug, Claude Opus 5.5 raised 1.7 false alarms per review and Gemini 4 Argon 1.1. A measured review cost $0.1525 on Claude Opus 5.5, 2.9× the cost of $0.0527 on Gemini 4 Argon.
| Pull request | Language · kind | Claude Opus 5.5 | Gemini 4 Argon |
|---|---|---|---|
| c-ares/c-aresEvent Thread could stall when not notified of new queries on existing connections that are in a bad state | C · Resource handling | 1/1 | 0/1 |
| colinhacks/zodfeat(v4): parse input containing reference cycles | TypeScript · Resource handling | 1/1 | 0/1 |
| golang/gocrypto/tls: add LocalCertificate to ConnectionState | Go · Logic | 1/1 | 0/1 |
| nodejs/undicifeat: add configurable maxPayloadSize for WebSocket | JavaScript · Security | 1/1 | 0/1 |
| nushell/nushellreorganize nushell configuration | Rust · Error handling | 1/1 | 0/1 |
| go-chi/chifeat: middleware.ClientIP, a replacement for middleware.RealIP | Go · Security | 0/1 | 1/1 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 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: Claude Opus 5.5 and Gemini 4 Argon.