Claude Opus 5.5 vs GPT-5.6 Sol
Claude Opus 5.5 and GPT-5.6 Sol charge practically the same to read a 26.2K-token pull request ($0.1048). Above 272K tokens long-context rates apply, and Claude Opus 5.5 becomes the cheaper one. Both sit in the frontier price tier, so the choice between them is about review quality more than budget. The benchmark cannot separate their recall: Claude Opus 5.5 minus GPT-5.6 Sol is +17 pts (95% interval +5 pts to +31 pts).
Side by side
| Figure | Claude Opus 5.5 | GPT-5.6 Sol |
|---|---|---|
| Price tier | Frontier | Frontier |
| Bugs caughtshare of known bugs | 90% (better) | 72% |
| False alarmsper clean PR | 1.7 | 1.2 (better) |
| Cost per reviewmeasured | $0.1525 | $0.1127 (better) |
| Cost per bug caught | $0.1921 | $0.1732 (better) |
| Exact linecatches on the expected lines | 89% | 92% (better) |
| Review timemean | 33s (better) | 50s |
| Typical review calllist price | $0.1532 | $0.1532 |
| Input / 1M tokens | $4.00 | $4.00 |
| Output / 1M tokens | $20.00 | $20.00 |
| Context window | 1M | 1.1M |
- Above 272K tokens, long-context rates mean Claude Opus 5.5 is the cheaper of the two.
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% |
| GPT-5.6 Sol | 72% | 67% | 50% | 69% | 75% | 56% | 100% | 67% | 100% | 100% | 67% | 100% | 50% | 0% |
Of the 42 known bugs both were scored on, both caught 31 and neither caught 2. Claude Opus 5.5 caught 8 bugs that GPT-5.6 Sol missed: 2 in TypeScript, 1 in C, 1 in C++, 1 in C#, 1 in Go, 1 in Ruby and 1 in Rust. GPT-5.6 Sol caught one bug that Claude Opus 5.5 missed: 1 in Go.
On pull requests with no known bug, Claude Opus 5.5 raised 1.7 false alarms per review and GPT-5.6 Sol 1.2. A measured review cost $0.1525 on Claude Opus 5.5, 35% more than $0.1127 on GPT-5.6 Sol.
| Pull request | Language · kind | Claude Opus 5.5 | GPT-5.6 Sol |
|---|---|---|---|
| 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 |
| 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 |
| nushell/nushellreorganize nushell configuration | Rust · Error handling | 1/1 | 0/1 |
| traefik/traefikAdd the option to define custom cipher suites for backend serversTransport | Go · API misuse | 1/1 | 0/1 |
| trpc/trpcfix(server): pass maxDurationMs timeout signal to subscription handlers | TypeScript · Concurrency | 1/1 | 0/1 |
| withastro/astroPort Go's csrf protection | TypeScript · Logic | 1/1 | 0/1 |
| rails/railsReimplement Action Cable redis adapter with redis-client | Ruby · Logic | 2/3 | 0/1 |
| go-chi/chifeat: middleware.ClientIP, a replacement for middleware.RealIP | Go · 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: Claude Opus 5.5 and GPT-5.6 Sol.