Gemini 3.1 Pro vs GLM-5.3 Flash (Workers AI)
Reading a 26.2K-token pull request costs $0.0524 on Gemini 3.1 Pro, 13× the $0.0039 it costs on GLM-5.3 Flash (Workers AI). Gemini 3.1 Pro is a mid-range model and GLM-5.3 Flash (Workers AI) a economy one. The benchmark cannot separate their recall: Gemini 3.1 Pro minus GLM-5.3 Flash (Workers AI) is +7 pts (95% interval −6 pts to +18 pts).
Side by side
| Figure | Gemini 3.1 Pro | GLM-5.3 Flash (Workers AI) |
|---|---|---|
| Price tier | Mid-range | Economy |
| Bugs caughtshare of known bugs | 67% (better) | 61% |
| False alarmsper clean PR | 0.8 (better) | 1.8 |
| Cost per reviewmeasured | $0.2499 | $0.0035 (better) |
| Cost per bug caught | $0.4134 | $0.0066 (better) |
| Exact linecatches on the expected lines | 89% (better) | 89% |
| Review timemean | 349s | 254s (better) |
| Typical review calllist price | $0.0814 | $0.0051 (better) |
| Input / 1M tokens | $2.00 | $0.15 (better) |
| Output / 1M tokens | $12.00 | $0.50 (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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gemini 3.1 Pro | 67% | 67% | 38% | 78% | 88% | 56% | 33% | 67% | 67% | 67% | 100% | 100% | 50% | 50% |
| GLM-5.3 Flash (Workers AI) | 61% | 57% | 31% | 45% | 88% | 30% | 67% | 89% | 33% | 78% | 67% | 67% | 100% | 67% |
Of the 42 known bugs both were scored on, both caught 31 and neither caught 6. Gemini 3.1 Pro caught one bug that GLM-5.3 Flash (Workers AI) missed: 1 in PHP. GLM-5.3 Flash (Workers AI) caught 4 bugs that Gemini 3.1 Pro missed: 2 in JavaScript, 1 in C++ and 1 in Kotlin.
On pull requests with no known bug, Gemini 3.1 Pro raised 0.8 false alarms per review and GLM-5.3 Flash (Workers AI) 1.8. A measured review cost $0.2499 on Gemini 3.1 Pro, 71× the cost of $0.0035 on GLM-5.3 Flash (Workers AI).
| Pull request | Language · kind | Gemini 3.1 Pro | GLM-5.3 Flash (Workers AI) |
|---|---|---|---|
| doctrine/ormFix collection filtering API for IN/NOT IN comparisons that require type conversions | PHP · Logic | 1/1 | 0/3 |
| ggml-org/llama.cpprpc : cache and reuse compute graphs | C++ · Security | 0/1 | 3/3 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 0/1 | 2/3 |
| nodejs/undicifeat: add configurable maxPayloadSize for WebSocket | JavaScript · Security | 0/1 | 3/3 |
| sindresorhus/p-throttleAdd `weight` option | JavaScript · Logic | 0/1 | 2/3 |
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 3.1 Pro and GLM-5.3 Flash (Workers AI).