Claude Opus 5.5 vs DeepSeek V4 Pro (Workers AI)
Reading a 26.2K-token pull request costs $0.1048 on Claude Opus 5.5, 3.0× the $0.0346 it costs on DeepSeek V4 Pro (Workers AI). Claude Opus 5.5 is a frontier model and DeepSeek V4 Pro (Workers AI) a mid-range one. In the benchmark Claude Opus 5.5 caught 36 percentage points more of the known defects than DeepSeek V4 Pro (Workers AI) (95% interval +24 pts to +48 pts, a − b).
Side by side
| Figure | Claude Opus 5.5 | DeepSeek V4 Pro (Workers AI) |
|---|---|---|
| Price tier | Frontier | Mid-range |
| Bugs caughtshare of known bugs | 90% (better) | 54% |
| False alarmsper clean PR | 1.7 (better) | 2.9 |
| Cost per reviewmeasured | $0.1525 | $0.0643 (better) |
| Cost per bug caught | $0.1921 | $0.0872 (better) |
| Exact linecatches on the expected lines | 89% (better) | 89% |
| Review timemean | 33s (better) | 390s |
| Typical review calllist price | $0.1532 | $0.0442 (better) |
| Input / 1M tokens | $4.00 | $1.32 (better) |
| Output / 1M tokens | $20.00 | $3.96 (better) |
| Context window | 1M | 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Claude Opus 5.5 | 90% | 100% | 50% | 78% | 100% | 100% | 100% | 67% | 100% | 100% | 89% | 100% | 100% | 100% |
| DeepSeek V4 Pro (Workers AI) | 54% | 79% | 25% | 49% | 54% | 59% | 17% | 30% | 69% | 72% | 67% | 75% | 38% | 33% |
Of the 42 known bugs both were scored on, both caught 33 and neither caught 2. Claude Opus 5.5 caught 6 bugs that DeepSeek V4 Pro (Workers AI) missed: 2 in JavaScript, 1 in C#, 1 in Go, 1 in Rust and 1 in TypeScript. DeepSeek V4 Pro (Workers AI) caught one bug that Claude Opus 5.5 missed: 1 in Kotlin.
On pull requests with no known bug, Claude Opus 5.5 raised 1.7 false alarms per review and DeepSeek V4 Pro (Workers AI) 2.9. A measured review cost $0.1525 on Claude Opus 5.5, 2.4× the cost of $0.0643 on DeepSeek V4 Pro (Workers AI).
| Pull request | Language · kind | Claude Opus 5.5 | DeepSeek V4 Pro (Workers AI) |
|---|---|---|---|
| colinhacks/zodfeat(v4): parse input containing reference cycles | TypeScript · Resource handling | 1/1 | 0/4 |
| denoland/denoperf(libs/core): poll only ready handles and yield between I/O batches | Rust · Concurrency | 1/1 | 0/4 |
| dotnet/orleansfix(serialization): cap codec allocations | C# · Logic | 1/1 | 0/4 |
| golang/gocrypto/tls: add LocalCertificate to ConnectionState | Go · Logic | 1/1 | 0/4 |
| pinojs/thread-streamrefactor: replace setTimeout with Atomics.waitAsync | JavaScript · Concurrency | 1/1 | 0/4 |
| sindresorhus/p-throttleAdd `weight` option | JavaScript · Logic | 1/1 | 0/4 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 0/1 | 2/4 |
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 DeepSeek V4 Pro (Workers AI).