GLM 5.3 Flash vs GPT 6 Luna
GPT 6 Luna cheaper in both pairings. GLM 5.3 Flash has a slight quality edge in every pairing; none is a clear lead. 2 pairings; 24 merged changes in Stet-AI/stet. Compare the individual calls below to choose which setup to investigate.
What this comparison is
- 1 real repositoryStet-AI/stet, private; not public benchmark scores
- 24 merged changeseach run end to end by the coding agent from the repo as it was before the change
- Graded against the merged changeby the repo’s own tests and by judges comparing each patch with it
- Quality, cost and timea smaller sample than public benchmarks, but real agent work on a real codebase
Compare coding modelsLow vs high vs xhigh/max reasoning for coding agents
Recorded setup pairings
Each row is a separate recorded comparison. Scores are not pooled or averaged across effort settings. W/D/L means wins, draws and losses; undecided judgments remain undecided.
Stet score: A setup’s average chance of beating another setup on a task, from 0 to 100; 50 is even with the field.
| Setup pairing | Recorded quality call and record | Quality evidence | Cost per task | Agent time per task |
|---|---|---|---|---|
| GLM 5.3 Flash high vs GPT 6 Luna maxGLM 5.3 Flash high · high reasoningGPT 6 Luna max · max reasoning20/24 tasks observed by both setups. | GLM 5.3 Flash high has a slight quality edge, 4–2 head to head with 13 tied and 5 undecided; GPT 6 Luna max leads on cost: 1.2× cheaper; GLM 5.3 Flash high leads on agent time: 2.2× faster.Head to head, GLM 5.3 Flash high won 4, tied 13 and lost 2 against GPT 6 Luna max, with 5 undecided. | Slight edge 4–2 head to head, 13 tiedGLM 5.3 Flash high: 47.8 (95% range 40.8–54.9)GPT 6 Luna max: 46.0 (95% range 40.4–51.6) | GLM 5.3 Flash high: $0.45 (from 20/24 tasks) GPT 6 Luna max: $0.37 | GLM 5.3 Flash high: 26.6 min (from 20/24 tasks) GPT 6 Luna max: 59.7 min |
| GLM 5.3 Flash high vs GPT 6 Luna lowGLM 5.3 Flash high · high reasoningGPT 6 Luna low · low reasoning20/24 tasks observed by both setups. | GLM 5.3 Flash high has a slight quality edge, 6–1 head to head with 12 tied and 5 undecided; GPT 6 Luna low leads on cost and agent time: 8.4× cheaper and 3.9× faster.Head to head, GLM 5.3 Flash high won 6, tied 12 and lost 1 against GPT 6 Luna low, with 5 undecided. | Slight edge 6–1 head to head, 12 tiedGLM 5.3 Flash high: 47.8 (95% range 40.8–54.9)GPT 6 Luna low: 37.8 (95% range 27.8–47.7) | GLM 5.3 Flash high: $0.45 (from 20/24 tasks) GPT 6 Luna low: $0.05 | GLM 5.3 Flash high: 26.6 min (from 20/24 tasks) GPT 6 Luna low: 6.9 min |
Questions about these results
- Which is better for coding, GLM 5.3 Flash or GPT 6 Luna?
- GPT 6 Luna cheaper in both pairings. GLM 5.3 Flash has a slight quality edge in every pairing; none is a clear lead. 2 pairings; 24 merged changes in Stet-AI/stet. Compare the individual calls below to choose which setup to investigate.
- Where do these coding results come from?
- Both coding agents worked the same 24 merged changes from the private Stet-AI/stet repository, each in the real repo as it was before the change. The repo’s tests and judges graded every patch against the merged change; no public benchmark scores are used.
- Are reasoning settings combined into one model score?
- No. Each effort pairing keeps its own recorded quality call, head-to-head record, cost and agent time. Incompatible scores are never averaged.