gpt-5.6-luna vs kimi-k3-256k
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
| Dimension | gpt-5.6-luna | kimi-k3-256k | Advantage |
|---|---|---|---|
| Capability | 53% | 57% | +3% (kimi-k3-256k leads) |
| Median task time | 1m 59s | 3m 3s | 1m 4s faster (gpt-5.6-luna leads) |
| Approx. task cost | $0.009 / task | $0.018 / task | $0.009 / task lower (gpt-5.6-luna leads) |
gpt-5.6-luna: 2.9% of ChatGPT Plus (2.9% / 1w) per run. kimi-k3-256k: 99.0% of Kimi Allegretto (99.0% / 5h, 20.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | gpt-5.6-luna | kimi-k3-256k | Advantage |
|---|---|---|---|
| Capability | 58% | 51% | +6% (gpt-5.6-luna leads) |
| Median task time | 2m 11s | 5m 16s | 3m 5s faster (gpt-5.6-luna leads) |
| Approx. task cost | $0.004 / task | $0.034 / task | $0.030 / task lower (gpt-5.6-luna leads) |
gpt-5.6-luna: 0.3% of ChatGPT Plus (0.3% / 1w) per run. kimi-k3-256k: 51.0% of Kimi Allegretto (51.0% / 5h, 10.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | gpt-5.6-luna | kimi-k3-256k | Advantage |
|---|---|---|---|
| Capability | 28% | 38% | +10% (kimi-k3-256k leads) |
| Median task time | 2m 44s | 6m 37s | 3m 54s faster (gpt-5.6-luna leads) |
| Approx. task cost | $0.008 / task | $0.027 / task | $0.020 / task lower (gpt-5.6-luna leads) |
gpt-5.6-luna: 0.2% of ChatGPT Plus (0.2% / 1w) per good solve. kimi-k3-256k: 10.2% of Kimi Allegretto (10.2% / 5h, 2.0% / 1w) per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, gpt-5.6-luna or kimi-k3-256k?
gpt-5.6-luna clears higher: tier 3 of 5 versus tier 2 for kimi-k3-256k on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-08-17.
How much do gpt-5.6-luna and kimi-k3-256k cost?
gpt-5.6-luna runs on ChatGPT Plus at $20/month (public price as of 2026-07-20). kimi-k3-256k runs on Kimi Allegretto at $39/month (public price as of 2026-07-20).